# sql.py # Copyright (C) 2005, 2006, 2007, 2008 Michael Bayer mike_mp@zzzcomputing.com # # This module is part of SQLAlchemy and is released under # the MIT License: http://www.opensource.org/licenses/mit-license.php """Defines the base components of SQL expression trees. All components are derived from a common base class [sqlalchemy.sql.expression#ClauseElement]. Common behaviors are organized based on class hierarchies, in some cases via mixins. All object construction from this package occurs via functions which in some cases will construct composite ``ClauseElement`` structures together, and in other cases simply return a single ``ClauseElement`` constructed directly. The function interface affords a more "DSL-ish" feel to constructing SQL expressions and also allows future class reorganizations. Even though classes are not constructed directly from the outside, most classes which have additional public methods are considered to be public (i.e. have no leading underscore). Other classes which are "semi-public" are marked with a single leading underscore; these classes usually have few or no public methods and are less guaranteed to stay the same in future releases. """ import itertools, re from sqlalchemy import util, exceptions from sqlalchemy.sql import operators, visitors from sqlalchemy import types as sqltypes functions, schema, sql_util = None, None, None DefaultDialect, ClauseAdapter = None, None __all__ = [ 'Alias', 'ClauseElement', 'ColumnCollection', 'ColumnElement', 'CompoundSelect', 'Delete', 'FromClause', 'Insert', 'Join', 'Select', 'Selectable', 'TableClause', 'Update', 'alias', 'and_', 'asc', 'between', 'bindparam', 'case', 'cast', 'column', 'delete', 'desc', 'distinct', 'except_', 'except_all', 'exists', 'extract', 'func', 'modifier', 'collate', 'insert', 'intersect', 'intersect_all', 'join', 'literal', 'literal_column', 'not_', 'null', 'or_', 'outparam', 'outerjoin', 'select', 'subquery', 'table', 'text', 'union', 'union_all', 'update', ] def desc(column): """Return a descending ``ORDER BY`` clause element. e.g.:: order_by = [desc(table1.mycol)] """ return _UnaryExpression(column, modifier=operators.desc_op) def asc(column): """Return an ascending ``ORDER BY`` clause element. e.g.:: order_by = [asc(table1.mycol)] """ return _UnaryExpression(column, modifier=operators.asc_op) def outerjoin(left, right, onclause=None): """Return an ``OUTER JOIN`` clause element. The returned object is an instance of [sqlalchemy.sql.expression#Join]. Similar functionality is also available via the ``outerjoin()`` method on any [sqlalchemy.sql.expression#FromClause]. left The left side of the join. right The right side of the join. onclause Optional criterion for the ``ON`` clause, is derived from foreign key relationships established between left and right otherwise. To chain joins together, use the ``join()`` or ``outerjoin()`` methods on the resulting ``Join`` object. """ return Join(left, right, onclause, isouter=True) def join(left, right, onclause=None, isouter=False): """Return a ``JOIN`` clause element (regular inner join). The returned object is an instance of [sqlalchemy.sql.expression#Join]. Similar functionality is also available via the ``join()`` method on any [sqlalchemy.sql.expression#FromClause]. left The left side of the join. right The right side of the join. onclause Optional criterion for the ``ON`` clause, is derived from foreign key relationships established between left and right otherwise. To chain joins together, use the ``join()`` or ``outerjoin()`` methods on the resulting ``Join`` object. """ return Join(left, right, onclause, isouter) def select(columns=None, whereclause=None, from_obj=[], **kwargs): """Returns a ``SELECT`` clause element. Similar functionality is also available via the ``select()`` method on any [sqlalchemy.sql.expression#FromClause]. The returned object is an instance of [sqlalchemy.sql.expression#Select]. All arguments which accept ``ClauseElement`` arguments also accept string arguments, which will be converted as appropriate into either ``text()`` or ``literal_column()`` constructs. columns A list of ``ClauseElement`` objects, typically ``ColumnElement`` objects or subclasses, which will form the columns clause of the resulting statement. For all members which are instances of ``Selectable``, the individual ``ColumnElement`` members of the ``Selectable`` will be added individually to the columns clause. For example, specifying a ``Table`` instance will result in all the contained ``Column`` objects within to be added to the columns clause. This argument is not present on the form of ``select()`` available on ``Table``. whereclause A ``ClauseElement`` expression which will be used to form the ``WHERE`` clause. from_obj A list of ``ClauseElement`` objects which will be added to the ``FROM`` clause of the resulting statement. Note that "from" objects are automatically located within the columns and whereclause ClauseElements. Use this parameter to explicitly specify "from" objects which are not automatically locatable. This could include ``Table`` objects that aren't otherwise present, or ``Join`` objects whose presence will supercede that of the ``Table`` objects already located in the other clauses. \**kwargs Additional parameters include: autocommit indicates this SELECT statement modifies the database, and should be subject to autocommit behavior if no transaction has been started. prefixes a list of strings or ``ClauseElement`` objects to include directly after the SELECT keyword in the generated statement, for dialect-specific query features. distinct=False when ``True``, applies a ``DISTINCT`` qualifier to the columns clause of the resulting statement. use_labels=False when ``True``, the statement will be generated using labels for each column in the columns clause, which qualify each column with its parent table's (or aliases) name so that name conflicts between columns in different tables don't occur. The format of the label is _. The "c" collection of the resulting ``Select`` object will use these names as well for targeting column members. for_update=False when ``True``, applies ``FOR UPDATE`` to the end of the resulting statement. Certain database dialects also support alternate values for this parameter, for example mysql supports "read" which translates to ``LOCK IN SHARE MODE``, and oracle supports "nowait" which translates to ``FOR UPDATE NOWAIT``. correlate=True indicates that this ``Select`` object should have its contained ``FromClause`` elements "correlated" to an enclosing ``Select`` object. This means that any ``ClauseElement`` instance within the "froms" collection of this ``Select`` which is also present in the "froms" collection of an enclosing select will not be rendered in the ``FROM`` clause of this select statement. group_by a list of ``ClauseElement`` objects which will comprise the ``GROUP BY`` clause of the resulting select. having a ``ClauseElement`` that will comprise the ``HAVING`` clause of the resulting select when ``GROUP BY`` is used. order_by a scalar or list of ``ClauseElement`` objects which will comprise the ``ORDER BY`` clause of the resulting select. limit=None a numerical value which usually compiles to a ``LIMIT`` expression in the resulting select. Databases that don't support ``LIMIT`` will attempt to provide similar functionality. offset=None a numeric value which usually compiles to an ``OFFSET`` expression in the resulting select. Databases that don't support ``OFFSET`` will attempt to provide similar functionality. bind=None an ``Engine`` or ``Connection`` instance to which the resulting ``Select ` object will be bound. The ``Select`` object will otherwise automatically bind to whatever ``Connectable`` instances can be located within its contained ``ClauseElement`` members. scalar=False deprecated. Use select(...).as_scalar() to create a "scalar column" proxy for an existing Select object. """ if 'scalar' in kwargs: util.warn_deprecated('scalar option is deprecated; see docs for details') scalar = kwargs.pop('scalar', False) s = Select(columns, whereclause=whereclause, from_obj=from_obj, **kwargs) if scalar: return s.as_scalar() else: return s def subquery(alias, *args, **kwargs): """Return an [sqlalchemy.sql.expression#Alias] object derived from a [sqlalchemy.sql.expression#Select]. name alias name \*args, \**kwargs all other arguments are delivered to the [sqlalchemy.sql.expression#select()] function. """ return Select(*args, **kwargs).alias(alias) def insert(table, values=None, inline=False, **kwargs): """Return an [sqlalchemy.sql.expression#Insert] clause element. Similar functionality is available via the ``insert()`` method on [sqlalchemy.schema#Table]. table The table to be inserted into. values A dictionary which specifies the column specifications of the ``INSERT``, and is optional. If left as None, the column specifications are determined from the bind parameters used during the compile phase of the ``INSERT`` statement. If the bind parameters also are None during the compile phase, then the column specifications will be generated from the full list of table columns. prefixes A list of modifier keywords to be inserted between INSERT and INTO, see ``Insert.prefix_with``. inline if True, SQL defaults will be compiled 'inline' into the statement and not pre-executed. If both `values` and compile-time bind parameters are present, the compile-time bind parameters override the information specified within `values` on a per-key basis. The keys within `values` can be either ``Column`` objects or their string identifiers. Each key may reference one of: * a literal data value (i.e. string, number, etc.); * a Column object; * a SELECT statement. If a ``SELECT`` statement is specified which references this ``INSERT`` statement's table, the statement will be correlated against the ``INSERT`` statement. """ return Insert(table, values, inline=inline, **kwargs) def update(table, whereclause=None, values=None, inline=False, **kwargs): """Return an [sqlalchemy.sql.expression#Update] clause element. Similar functionality is available via the ``update()`` method on [sqlalchemy.schema#Table]. table The table to be updated. whereclause A ``ClauseElement`` describing the ``WHERE`` condition of the ``UPDATE`` statement. values A dictionary which specifies the ``SET`` conditions of the ``UPDATE``, and is optional. If left as None, the ``SET`` conditions are determined from the bind parameters used during the compile phase of the ``UPDATE`` statement. If the bind parameters also are None during the compile phase, then the ``SET`` conditions will be generated from the full list of table columns. inline if True, SQL defaults will be compiled 'inline' into the statement and not pre-executed. If both `values` and compile-time bind parameters are present, the compile-time bind parameters override the information specified within `values` on a per-key basis. The keys within `values` can be either ``Column`` objects or their string identifiers. Each key may reference one of: * a literal data value (i.e. string, number, etc.); * a Column object; * a SELECT statement. If a ``SELECT`` statement is specified which references this ``UPDATE`` statement's table, the statement will be correlated against the ``UPDATE`` statement. """ return Update(table, whereclause=whereclause, values=values, inline=inline, **kwargs) def delete(table, whereclause = None, **kwargs): """Return a [sqlalchemy.sql.expression#Delete] clause element. Similar functionality is available via the ``delete()`` method on [sqlalchemy.schema#Table]. table The table to be updated. whereclause A ``ClauseElement`` describing the ``WHERE`` condition of the ``UPDATE`` statement. """ return Delete(table, whereclause, **kwargs) def and_(*clauses): """Join a list of clauses together using the ``AND`` operator. The ``&`` operator is also overloaded on all [sqlalchemy.sql.expression#_CompareMixin] subclasses to produce the same result. """ if len(clauses) == 1: return clauses[0] return ClauseList(operator=operators.and_, *clauses) def or_(*clauses): """Join a list of clauses together using the ``OR`` operator. The ``|`` operator is also overloaded on all [sqlalchemy.sql.expression#_CompareMixin] subclasses to produce the same result. """ if len(clauses) == 1: return clauses[0] return ClauseList(operator=operators.or_, *clauses) def not_(clause): """Return a negation of the given clause, i.e. ``NOT(clause)``. The ``~`` operator is also overloaded on all [sqlalchemy.sql.expression#_CompareMixin] subclasses to produce the same result. """ return operators.inv(_literal_as_binds(clause)) def distinct(expr): """Return a ``DISTINCT`` clause.""" return _UnaryExpression(expr, operator=operators.distinct_op) def between(ctest, cleft, cright): """Return a ``BETWEEN`` predicate clause. Equivalent of SQL ``clausetest BETWEEN clauseleft AND clauseright``. The ``between()`` method on all [sqlalchemy.sql.expression#_CompareMixin] subclasses provides similar functionality. """ ctest = _literal_as_binds(ctest) return _BinaryExpression(ctest, ClauseList(_literal_as_binds(cleft, type_=ctest.type), _literal_as_binds(cright, type_=ctest.type), operator=operators.and_, group=False), operators.between_op) def case(whens, value=None, else_=None): """Produce a ``CASE`` statement. whens A sequence of pairs, or alternatively a dict, to be translated into "WHEN / THEN" clauses. value Optional for simple case statements, produces a column expression as in "CASE WHEN ..." else\_ Optional as well, for case defaults produces the "ELSE" portion of the "CASE" statement. The expressions used for THEN and ELSE, when specified as strings, will be interpreted as bound values. To specify textual SQL expressions for these, use the text() construct. The expressions used for the WHEN criterion may only be literal strings when "value" is present, i.e. CASE table.somecol WHEN "x" THEN "y". Otherwise, literal strings are not accepted in this position, and either the text() or literal() constructs must be used to interpret raw string values. Usage examples:: case([(orderline.c.qty > 100, item.c.specialprice), (orderline.c.qty > 10, item.c.bulkprice) ], else_=item.c.regularprice) case(value=emp.c.type, whens={ 'engineer': emp.c.salary * 1.1, 'manager': emp.c.salary * 3, }) """ try: whens = util.dictlike_iteritems(whens) except TypeError: pass if value: crit_filter = _literal_as_binds else: crit_filter = _no_literals whenlist = [ClauseList('WHEN', crit_filter(c), 'THEN', _literal_as_binds(r), operator=None) for (c,r) in whens] if else_ is not None: whenlist.append(ClauseList('ELSE', _literal_as_binds(else_), operator=None)) if whenlist: type = list(whenlist[-1])[-1].type else: type = None cc = _CalculatedClause(None, 'CASE', value, type_=type, operator=None, group_contents=False, *whenlist + ['END']) return cc def cast(clause, totype, **kwargs): """Return a ``CAST`` function. Equivalent of SQL ``CAST(clause AS totype)``. Use with a [sqlalchemy.types#TypeEngine] subclass, i.e:: cast(table.c.unit_price * table.c.qty, Numeric(10,4)) or:: cast(table.c.timestamp, DATE) """ return _Cast(clause, totype, **kwargs) def extract(field, expr): """Return the clause ``extract(field FROM expr)``.""" expr = _BinaryExpression(text(field), expr, operators.from_) return func.extract(expr) def collate(expression, collation): """Return the clause ``expression COLLATE collation``.""" expr = _literal_as_binds(expression) return _CalculatedClause( expr, expr, _literal_as_text(collation), operator=operators.collate, group=False) def exists(*args, **kwargs): """Return an ``EXISTS`` clause as applied to a [sqlalchemy.sql.expression#Select] object. The resulting [sqlalchemy.sql.expression#_Exists] object can be executed by itself or used as a subquery within an enclosing select. \*args, \**kwargs all arguments are sent directly to the [sqlalchemy.sql.expression#select()] function to produce a ``SELECT`` statement. """ return _Exists(*args, **kwargs) def union(*selects, **kwargs): """Return a ``UNION`` of multiple selectables. The returned object is an instance of [sqlalchemy.sql.expression#CompoundSelect]. A similar ``union()`` method is available on all [sqlalchemy.sql.expression#FromClause] subclasses. \*selects a list of [sqlalchemy.sql.expression#Select] instances. \**kwargs available keyword arguments are the same as those of [sqlalchemy.sql.expression#select()]. """ return _compound_select('UNION', *selects, **kwargs) def union_all(*selects, **kwargs): """Return a ``UNION ALL`` of multiple selectables. The returned object is an instance of [sqlalchemy.sql.expression#CompoundSelect]. A similar ``union_all()`` method is available on all [sqlalchemy.sql.expression#FromClause] subclasses. \*selects a list of [sqlalchemy.sql.expression#Select] instances. \**kwargs available keyword arguments are the same as those of [sqlalchemy.sql.expression#select()]. """ return _compound_select('UNION ALL', *selects, **kwargs) def except_(*selects, **kwargs): """Return an ``EXCEPT`` of multiple selectables. The returned object is an instance of [sqlalchemy.sql.expression#CompoundSelect]. \*selects a list of [sqlalchemy.sql.expression#Select] instances. \**kwargs available keyword arguments are the same as those of [sqlalchemy.sql.expression#select()]. """ return _compound_select('EXCEPT', *selects, **kwargs) def except_all(*selects, **kwargs): """Return an ``EXCEPT ALL`` of multiple selectables. The returned object is an instance of [sqlalchemy.sql.expression#CompoundSelect]. \*selects a list of [sqlalchemy.sql.expression#Select] instances. \**kwargs available keyword arguments are the same as those of [sqlalchemy.sql.expression#select()]. """ return _compound_select('EXCEPT ALL', *selects, **kwargs) def intersect(*selects, **kwargs): """Return an ``INTERSECT`` of multiple selectables. The returned object is an instance of [sqlalchemy.sql.expression#CompoundSelect]. \*selects a list of [sqlalchemy.sql.expression#Select] instances. \**kwargs available keyword arguments are the same as those of [sqlalchemy.sql.expression#select()]. """ return _compound_select('INTERSECT', *selects, **kwargs) def intersect_all(*selects, **kwargs): """Return an ``INTERSECT ALL`` of multiple selectables. The returned object is an instance of [sqlalchemy.sql.expression#CompoundSelect]. \*selects a list of [sqlalchemy.sql.expression#Select] instances. \**kwargs available keyword arguments are the same as those of [sqlalchemy.sql.expression#select()]. """ return _compound_select('INTERSECT ALL', *selects, **kwargs) def alias(selectable, alias=None): """Return an [sqlalchemy.sql.expression#Alias] object. An ``Alias`` represents any [sqlalchemy.sql.expression#FromClause] with an alternate name assigned within SQL, typically using the ``AS`` clause when generated, e.g. ``SELECT * FROM table AS aliasname``. Similar functionality is available via the ``alias()`` method available on all ``FromClause`` subclasses. selectable any ``FromClause`` subclass, such as a table, select statement, etc.. alias string name to be assigned as the alias. If ``None``, a random name will be generated. """ return Alias(selectable, alias=alias) def literal(value, type_=None): """Return a literal clause, bound to a bind parameter. Literal clauses are created automatically when non- ``ClauseElement`` objects (such as strings, ints, dates, etc.) are used in a comparison operation with a [sqlalchemy.sql.expression#_CompareMixin] subclass, such as a ``Column`` object. Use this function to force the generation of a literal clause, which will be created as a [sqlalchemy.sql.expression#_BindParamClause] with a bound value. value the value to be bound. Can be any Python object supported by the underlying DB-API, or is translatable via the given type argument. type\_ an optional [sqlalchemy.types#TypeEngine] which will provide bind-parameter translation for this literal. """ return _BindParamClause(None, value, type_=type_, unique=True) def label(name, obj): """Return a [sqlalchemy.sql.expression#_Label] object for the given [sqlalchemy.sql.expression#ColumnElement]. A label changes the name of an element in the columns clause of a ``SELECT`` statement, typically via the ``AS`` SQL keyword. This functionality is more conveniently available via the ``label()`` method on ``ColumnElement``. name label name obj a ``ColumnElement``. """ return _Label(name, obj) def column(text, type_=None): """Return a textual column clause, as would be in the columns clause of a ``SELECT`` statement. The object returned is an instance of [sqlalchemy.sql.expression#_ColumnClause], which represents the "syntactical" portion of the schema-level [sqlalchemy.schema#Column] object. text the name of the column. Quoting rules will be applied to the clause like any other column name. For textual column constructs that are not to be quoted, use the [sqlalchemy.sql.expression#literal_column()] function. type\_ an optional [sqlalchemy.types#TypeEngine] object which will provide result-set translation for this column. """ return _ColumnClause(text, type_=type_) def literal_column(text, type_=None): """Return a textual column expression, as would be in the columns clause of a ``SELECT`` statement. The object returned supports further expressions in the same way as any other column object, including comparison, math and string operations. The type\_ parameter is important to determine proper expression behavior (such as, '+' means string concatenation or numerical addition based on the type). text the text of the expression; can be any SQL expression. Quoting rules will not be applied. To specify a column-name expression which should be subject to quoting rules, use the [sqlalchemy.sql.expression#column()] function. type\_ an optional [sqlalchemy.types#TypeEngine] object which will provide result-set translation and additional expression semantics for this column. If left as None the type will be NullType. """ return _ColumnClause(text, type_=type_, is_literal=True) def table(name, *columns): """Return a [sqlalchemy.sql.expression#Table] object. This is a primitive version of the [sqlalchemy.schema#Table] object, which is a subclass of this object. """ return TableClause(name, *columns) def bindparam(key, value=None, shortname=None, type_=None, unique=False): """Create a bind parameter clause with the given key. value a default value for this bind parameter. a bindparam with a value is called a ``value-based bindparam``. type\_ a sqlalchemy.types.TypeEngine object indicating the type of this bind param, will invoke type-specific bind parameter processing shortname deprecated. unique if True, bind params sharing the same name will have their underlying ``key`` modified to a uniquely generated name. mostly useful with value-based bind params. """ if isinstance(key, _ColumnClause): return _BindParamClause(key.name, value, type_=key.type, unique=unique, shortname=shortname) else: return _BindParamClause(key, value, type_=type_, unique=unique, shortname=shortname) def outparam(key, type_=None): """Create an 'OUT' parameter for usage in functions (stored procedures), for databases which support them. The ``outparam`` can be used like a regular function parameter. The "output" value will be available from the [sqlalchemy.engine#ResultProxy] object via its ``out_parameters`` attribute, which returns a dictionary containing the values. """ return _BindParamClause(key, None, type_=type_, unique=False, isoutparam=True) def text(text, bind=None, *args, **kwargs): """Create literal text to be inserted into a query. When constructing a query from a ``select()``, ``update()``, ``insert()`` or ``delete()``, using plain strings for argument values will usually result in text objects being created automatically. Use this function when creating textual clauses outside of other ``ClauseElement`` objects, or optionally wherever plain text is to be used. text the text of the SQL statement to be created. use ``:`` to specify bind parameters; they will be compiled to their engine-specific format. bind an optional connection or engine to be used for this text query. autocommit=True indicates this SELECT statement modifies the database, and should be subject to autocommit behavior if no transaction has been started. bindparams a list of ``bindparam()`` instances which can be used to define the types and/or initial values for the bind parameters within the textual statement; the keynames of the bindparams must match those within the text of the statement. The types will be used for pre-processing on bind values. typemap a dictionary mapping the names of columns represented in the ``SELECT`` clause of the textual statement to type objects, which will be used to perform post-processing on columns within the result set (for textual statements that produce result sets). """ return _TextClause(text, bind=bind, *args, **kwargs) def null(): """Return a ``_Null`` object, which compiles to ``NULL`` in a sql statement.""" return _Null() class _FunctionGenerator(object): """Generate ``_Function`` objects based on getattr calls.""" def __init__(self, **opts): self.__names = [] self.opts = opts def __getattr__(self, name): # passthru __ attributes; fixes pydoc if name.startswith('__'): try: return self.__dict__[name] except KeyError: raise AttributeError(name) elif name.endswith('_'): name = name[0:-1] f = _FunctionGenerator(**self.opts) f.__names = list(self.__names) + [name] return f def __call__(self, *c, **kwargs): o = self.opts.copy() o.update(kwargs) if len(self.__names) == 1: global functions if functions is None: from sqlalchemy.sql import functions func = getattr(functions, self.__names[-1].lower(), None) if func is not None: return func(*c, **o) return _Function(self.__names[-1], packagenames=self.__names[0:-1], *c, **o) # "func" global - i.e. func.count() func = _FunctionGenerator() # "modifier" global - i.e. modifier.distinct # TODO: use UnaryExpression for this instead ? modifier = _FunctionGenerator(group=False) def _clone(element): return element._clone() def _expand_cloned(elements): """expand the given set of ClauseElements to be the set of all 'cloned' predecessors.""" return itertools.chain(*[x._cloned_set for x in elements]) def _cloned_intersection(a, b): """return the intersection of sets a and b, counting any overlap between 'cloned' predecessors. The returned set is in terms of the enties present within 'a'. """ all_overlap = util.Set(_expand_cloned(a)).intersection(_expand_cloned(b)) return a.intersection( [ elem for elem in a if all_overlap.intersection(elem._cloned_set) ] ) def _compound_select(keyword, *selects, **kwargs): return CompoundSelect(keyword, *selects, **kwargs) def _is_literal(element): return not isinstance(element, ClauseElement) def _literal_as_text(element): if isinstance(element, Operators): return element.expression_element() elif _is_literal(element): return _TextClause(unicode(element)) else: return element def _literal_as_column(element): if isinstance(element, Operators): return element.clause_element() elif _is_literal(element): return literal_column(str(element)) else: return element def _literal_as_binds(element, name=None, type_=None): if isinstance(element, Operators): return element.expression_element() elif _is_literal(element): if element is None: return null() else: return _BindParamClause(name, element, type_=type_, unique=True) else: return element def _no_literals(element): if isinstance(element, Operators): return element.expression_element() elif _is_literal(element): raise exceptions.ArgumentError("Ambiguous literal: %r. Use the 'text()' function to indicate a SQL expression literal, or 'literal()' to indicate a bound value." % element) else: return element def _corresponding_column_or_error(fromclause, column, require_embedded=False): c = fromclause.corresponding_column(column, require_embedded=require_embedded) if not c: raise exceptions.InvalidRequestError("Given column '%s', attached to table '%s', failed to locate a corresponding column from table '%s'" % (str(column), str(getattr(column, 'table', None)), fromclause.description)) return c def _selectable(element): if hasattr(element, '__selectable__'): return element.__selectable__() elif isinstance(element, Selectable): return element else: raise exceptions.ArgumentError("Object '%s' is not a Selectable and does not implement `__selectable__()`" % repr(element)) def is_column(col): """True if ``col`` is an instance of ``ColumnElement``.""" return isinstance(col, ColumnElement) class _FigureVisitName(type): def __init__(cls, clsname, bases, dict): if not '__visit_name__' in cls.__dict__: m = re.match(r'_?(\w+?)(?:Expression|Clause|Element|$)', clsname) x = m.group(1) x = re.sub(r'(?!^)[A-Z]', lambda m:'_'+m.group(0).lower(), x) cls.__visit_name__ = x.lower() super(_FigureVisitName, cls).__init__(clsname, bases, dict) class ClauseElement(object): """Base class for elements of a programmatically constructed SQL expression.""" __metaclass__ = _FigureVisitName def _clone(self): """Create a shallow copy of this ClauseElement. This method may be used by a generative API. Its also used as part of the "deep" copy afforded by a traversal that combines the _copy_internals() method. """ c = self.__class__.__new__(self.__class__) c.__dict__ = self.__dict__.copy() # this is a marker that helps to "equate" clauses to each other # when a Select returns its list of FROM clauses. the cloning # process leaves around a lot of remnants of the previous clause # typically in the form of column expressions still attached to the # old table. c._is_clone_of = self return c def _cloned_set(self): f = self while f is not None: yield f f = getattr(f, '_is_clone_of', None) _cloned_set = property(_cloned_set) def _get_from_objects(self, **modifiers): """Return objects represented in this ``ClauseElement`` that should be added to the ``FROM`` list of a query, when this ``ClauseElement`` is placed in the column clause of a ``Select`` statement. """ raise NotImplementedError(repr(self)) def unique_params(self, *optionaldict, **kwargs): """Return a copy with ``bindparam()`` elments replaced. Same functionality as ``params()``, except adds `unique=True` to affected bind parameters so that multiple statements can be used. """ return self._params(True, optionaldict, kwargs) def params(self, *optionaldict, **kwargs): """Return a copy with ``bindparam()`` elments replaced. Returns a copy of this ClauseElement with ``bindparam()`` elements replaced with values taken from the given dictionary:: >>> clause = column('x') + bindparam('foo') >>> print clause.compile().params {'foo':None} >>> print clause.params({'foo':7}).compile().params {'foo':7} """ return self._params(False, optionaldict, kwargs) def _params(self, unique, optionaldict, kwargs): if len(optionaldict) == 1: kwargs.update(optionaldict[0]) elif len(optionaldict) > 1: raise exceptions.ArgumentError("params() takes zero or one positional dictionary argument") def visit_bindparam(bind): if bind.key in kwargs: bind.value = kwargs[bind.key] if unique: bind._convert_to_unique() return visitors.traverse(self, visit_bindparam=visit_bindparam, clone=True) def compare(self, other): """Compare this ClauseElement to the given ClauseElement. Subclasses should override the default behavior, which is a straight identity comparison. """ return self is other def _copy_internals(self, clone=_clone): """Reassign internal elements to be clones of themselves. Called during a copy-and-traverse operation on newly shallow-copied elements to create a deep copy. """ pass def get_children(self, **kwargs): """Return immediate child elements of this ``ClauseElement``. This is used for visit traversal. \**kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level). """ return [] def self_group(self, against=None): return self def supports_execution(self): """Return True if this clause element represents a complete executable statement.""" return False def bind(self): """Returns the Engine or Connection to which this ClauseElement is bound, or None if none found.""" try: if self._bind is not None: return self._bind except AttributeError: pass for f in self._get_from_objects(): if f is self: continue engine = f.bind if engine is not None: return engine else: return None bind = property(bind) def execute(self, *multiparams, **params): """Compile and execute this ``ClauseElement``.""" e = self.bind if e is None: label = getattr(self, 'description', self.__class__.__name__) msg = ('This %s is not bound and does not support direct ' 'execution. Supply this statement to a Connection or ' 'Engine for execution. Or, assign a bind to the statement ' 'or the Metadata of its underlying tables to enable ' 'implicit execution via this method.' % label) raise exceptions.UnboundExecutionError(msg) return e.execute_clauseelement(self, multiparams, params) def scalar(self, *multiparams, **params): """Compile and execute this ``ClauseElement``, returning the result's scalar representation.""" return self.execute(*multiparams, **params).scalar() def compile(self, bind=None, column_keys=None, compiler=None, dialect=None, inline=False): """Compile this SQL expression. Uses the given ``Compiler``, or the given ``AbstractDialect`` or ``Engine`` to create a ``Compiler``. If no `compiler` arguments are given, tries to use the underlying ``Engine`` this ``ClauseElement`` is bound to to create a ``Compiler``, if any. Finally, if there is no bound ``Engine``, uses an ``DefaultDialect`` to create a default ``Compiler``. `parameters` is a dictionary representing the default bind parameters to be used with the statement. If `parameters` is a list, it is assumed to be a list of dictionaries and the first dictionary in the list is used with which to compile against. The bind parameters can in some cases determine the output of the compilation, such as for ``UPDATE`` and ``INSERT`` statements the bind parameters that are present determine the ``SET`` and ``VALUES`` clause of those statements. """ if compiler is None: if dialect is not None: compiler = dialect.statement_compiler(dialect, self, column_keys=column_keys, inline=inline) elif bind is not None: compiler = bind.statement_compiler(self, column_keys=column_keys, inline=inline) elif self.bind is not None: compiler = self.bind.statement_compiler(self, column_keys=column_keys, inline=inline) if compiler is None: global DefaultDialect if DefaultDialect is None: from sqlalchemy.engine.default import DefaultDialect dialect = DefaultDialect() compiler = dialect.statement_compiler(dialect, self, column_keys=column_keys, inline=inline) compiler.compile() return compiler def __str__(self): return unicode(self.compile()).encode('ascii', 'backslashreplace') def __and__(self, other): return and_(self, other) def __or__(self, other): return or_(self, other) def __invert__(self): return self._negate() def _negate(self): if hasattr(self, 'negation_clause'): return self.negation_clause else: return _UnaryExpression(self.self_group(against=operators.inv), operator=operators.inv, negate=None) def __repr__(self): friendly = getattr(self, 'description', None) if friendly is None: return object.__repr__(self) else: return '<%s.%s at 0x%x; %s>' % ( self.__module__, self.__class__.__name__, id(self), friendly) class Operators(object): def __and__(self, other): return self.operate(operators.and_, other) def __or__(self, other): return self.operate(operators.or_, other) def __invert__(self): return self.operate(operators.inv) def op(self, opstring): def op(b): return self.operate(operators.op, opstring, b) return op def clause_element(self): raise NotImplementedError() def operate(self, op, *other, **kwargs): raise NotImplementedError() def reverse_operate(self, op, other, **kwargs): raise NotImplementedError() class ColumnOperators(Operators): """Defines comparison and math operations.""" timetuple = None """Hack, allows datetime objects to be compared on the LHS.""" def __lt__(self, other): return self.operate(operators.lt, other) def __le__(self, other): return self.operate(operators.le, other) def __eq__(self, other): return self.operate(operators.eq, other) def __ne__(self, other): return self.operate(operators.ne, other) def __gt__(self, other): return self.operate(operators.gt, other) def __ge__(self, other): return self.operate(operators.ge, other) def concat(self, other): return self.operate(operators.concat_op, other) def like(self, other, escape=None): return self.operate(operators.like_op, other, escape=escape) def ilike(self, other, escape=None): return self.operate(operators.ilike_op, other, escape=escape) def in_(self, *other): return self.operate(operators.in_op, other) def startswith(self, other, **kwargs): return self.operate(operators.startswith_op, other, **kwargs) def endswith(self, other, **kwargs): return self.operate(operators.endswith_op, other, **kwargs) def contains(self, other, **kwargs): return self.operate(operators.contains_op, other, **kwargs) def desc(self): return self.operate(operators.desc_op) def asc(self): return self.operate(operators.asc_op) def collate(self, collation): return self.operate(operators.collate, collation) def __radd__(self, other): return self.reverse_operate(operators.add, other) def __rsub__(self, other): return self.reverse_operate(operators.sub, other) def __rmul__(self, other): return self.reverse_operate(operators.mul, other) def __rdiv__(self, other): return self.reverse_operate(operators.div, other) def between(self, cleft, cright): return self.operate(operators.between_op, cleft, cright) def distinct(self): return self.operate(operators.distinct_op) def __add__(self, other): return self.operate(operators.add, other) def __sub__(self, other): return self.operate(operators.sub, other) def __mul__(self, other): return self.operate(operators.mul, other) def __div__(self, other): return self.operate(operators.div, other) def __mod__(self, other): return self.operate(operators.mod, other) def __truediv__(self, other): return self.operate(operators.truediv, other) class _CompareMixin(ColumnOperators): """Defines comparison and math operations for ``ClauseElement`` instances.""" def __compare(self, op, obj, negate=None, reverse=False, **kwargs): if obj is None or isinstance(obj, _Null): if op == operators.eq: return _BinaryExpression(self.expression_element(), null(), operators.is_, negate=operators.isnot) elif op == operators.ne: return _BinaryExpression(self.expression_element(), null(), operators.isnot, negate=operators.is_) else: raise exceptions.ArgumentError("Only '='/'!=' operators can be used with NULL") else: obj = self._check_literal(obj) if reverse: return _BinaryExpression(obj, self.expression_element(), op, type_=sqltypes.Boolean, negate=negate, modifiers=kwargs) else: return _BinaryExpression(self.expression_element(), obj, op, type_=sqltypes.Boolean, negate=negate, modifiers=kwargs) def __operate(self, op, obj, reverse=False): obj = self._check_literal(obj) type_ = self._compare_type(obj) if reverse: return _BinaryExpression(obj, self.expression_element(), type_.adapt_operator(op), type_=type_) else: return _BinaryExpression(self.expression_element(), obj, type_.adapt_operator(op), type_=type_) # a mapping of operators with the method they use, along with their negated # operator for comparison operators operators = { operators.add : (__operate,), operators.mul : (__operate,), operators.sub : (__operate,), operators.div : (__operate,), operators.mod : (__operate,), operators.truediv : (__operate,), operators.lt : (__compare, operators.ge), operators.le : (__compare, operators.gt), operators.ne : (__compare, operators.eq), operators.gt : (__compare, operators.le), operators.ge : (__compare, operators.lt), operators.eq : (__compare, operators.ne), operators.like_op : (__compare, operators.notlike_op), operators.ilike_op : (__compare, operators.notilike_op), } def operate(self, op, *other, **kwargs): o = _CompareMixin.operators[op] return o[0](self, op, other[0], *o[1:], **kwargs) def reverse_operate(self, op, other, **kwargs): o = _CompareMixin.operators[op] return o[0](self, op, other, reverse=True, *o[1:], **kwargs) def in_(self, *other): return self._in_impl(operators.in_op, operators.notin_op, *other) def _in_impl(self, op, negate_op, *other): # Handle old style *args argument passing if len(other) != 1 or not isinstance(other[0], (_ScalarSelect, Selectable)) and (not hasattr(other[0], '__iter__') or isinstance(other[0], basestring)): util.warn_deprecated('passing in_ arguments as varargs is deprecated, in_ takes a single argument that is a sequence or a selectable') seq_or_selectable = other else: seq_or_selectable = other[0] if isinstance(seq_or_selectable, _ScalarSelect): return self.__compare( op, seq_or_selectable, negate=negate_op) elif isinstance(seq_or_selectable, _SelectBaseMixin): return self.__compare( op, seq_or_selectable.as_scalar(), negate=negate_op) elif isinstance(seq_or_selectable, Selectable): return self.__compare( op, seq_or_selectable, negate=negate_op) # Handle non selectable arguments as sequences args = [] for o in seq_or_selectable: if not _is_literal(o): if not isinstance( o, _CompareMixin): raise exceptions.InvalidRequestError( "in() function accepts either a list of non-selectable values, or a selectable: "+repr(o) ) else: o = self._bind_param(o) args.append(o) if len(args) == 0: # Special case handling for empty IN's return _Grouping(case([(self.__eq__(None), text('NULL'))], else_=text('0')).__eq__(text('1'))) return self.__compare(op, ClauseList(*args).self_group(against=op), negate=negate_op) def startswith(self, other, escape=None): """Produce the clause ``LIKE '%'``""" # use __radd__ to force string concat behavior return self.__compare(operators.like_op, literal_column("'%'", type_=sqltypes.String).__radd__(self._check_literal(other)), escape=escape) def endswith(self, other, escape=None): """Produce the clause ``LIKE '%'``""" return self.__compare(operators.like_op, literal_column("'%'", type_=sqltypes.String) + self._check_literal(other), escape=escape) def contains(self, other, escape=None): """Produce the clause ``LIKE '%%'``""" return self.__compare(operators.like_op, literal_column("'%'", type_=sqltypes.String) + self._check_literal(other) + literal_column("'%'", type_=sqltypes.String), escape=escape) def label(self, name): """Produce a column label, i.e. `` AS ``. if 'name' is None, an anonymous label name will be generated. """ return _Label(name, self, self.type) def desc(self): """Produce a DESC clause, i.e. `` DESC``""" return desc(self) def asc(self): """Produce a ASC clause, i.e. `` ASC``""" return asc(self) def distinct(self): """Produce a DISTINCT clause, i.e. ``DISTINCT ``""" return _UnaryExpression(self, operator=operators.distinct_op) def between(self, cleft, cright): """Produce a BETWEEN clause, i.e. `` BETWEEN AND ``""" return _BinaryExpression(self, ClauseList(self._check_literal(cleft), self._check_literal(cright), operator=operators.and_, group=False), operators.between_op) def collate(self, collation): """Produce a COLLATE clause, i.e. `` COLLATE utf8_bin``""" name = getattr(self, 'name', None) return _CalculatedClause( None, self, _literal_as_text(collation), operator=operators.collate, group=False) def op(self, operator): """produce a generic operator function. e.g.:: somecolumn.op("*")(5) produces:: somecolumn * 5 operator a string which will be output as the infix operator between this ``ClauseElement`` and the expression passed to the generated function. """ return lambda other: self.__operate(operator, other) def _bind_param(self, obj): return _BindParamClause(None, obj, type_=self.type, unique=True) def _check_literal(self, other): if isinstance(other, _BindParamClause) and isinstance(other.type, sqltypes.NullType): other.type = self.type return other elif isinstance(other, Operators): return other.expression_element() elif _is_literal(other): return self._bind_param(other) else: return other def clause_element(self): """Allow ``_CompareMixins`` to return the underlying ``ClauseElement``, for non-``ClauseElement`` ``_CompareMixins``.""" return self def expression_element(self): """Allow ``_CompareMixins`` to return the appropriate object to be used in expressions.""" return self def _compare_type(self, obj): """Allow subclasses to override the type used in constructing ``_BinaryExpression`` objects. Default return value is the type of the given object. """ return obj.type class ColumnElement(ClauseElement, _CompareMixin): """Represent an element that is usable within the "column clause" portion of a ``SELECT`` statement. This includes columns associated with tables, aliases, and subqueries, expressions, function calls, SQL keywords such as ``NULL``, literals, etc. ``ColumnElement`` is the ultimate base class for all such elements. ``ColumnElement`` supports the ability to be a *proxy* element, which indicates that the ``ColumnElement`` may be associated with a ``Selectable`` which was derived from another ``Selectable``. An example of a "derived" ``Selectable`` is an ``Alias`` of a ``Table``. A ``ColumnElement``, by subclassing the ``_CompareMixin`` mixin class, provides the ability to generate new ``ClauseElement`` objects using Python expressions. See the ``_CompareMixin`` docstring for more details. """ primary_key = False foreign_keys = [] def base_columns(self): if hasattr(self, '_base_columns'): return self._base_columns self._base_columns = util.Set([c for c in self.proxy_set if not hasattr(c, 'proxies')]) return self._base_columns base_columns = property(base_columns) def proxy_set(self): if hasattr(self, '_proxy_set'): return self._proxy_set s = util.Set([self]) if hasattr(self, 'proxies'): for c in self.proxies: s = s.union(c.proxy_set) self._proxy_set = s return s proxy_set = property(proxy_set) def shares_lineage(self, othercolumn): """Return True if the given ``ColumnElement`` has a common ancestor to this ``ColumnElement``. """ return len(self.proxy_set.intersection(othercolumn.proxy_set)) > 0 def _make_proxy(self, selectable, name=None): """Create a new ``ColumnElement`` representing this ``ColumnElement`` as it appears in the select list of a descending selectable. """ if name: co = _ColumnClause(name, selectable, type_=getattr(self, 'type', None)) else: name = str(self) co = _ColumnClause(self.anon_label, selectable, type_=getattr(self, 'type', None)) co.proxies = [self] selectable.columns[name]= co return co def anon_label(self): """provides a constant 'anonymous label' for this ColumnElement. This is a label() expression which will be named at compile time. The same label() is returned each time anon_label is called so that expressions can reference anon_label multiple times, producing the same label name at compile time. the compiler uses this function automatically at compile time for expressions that are known to be 'unnamed' like binary expressions and function calls. """ if not hasattr(self, '_ColumnElement__anon_label'): self.__anon_label = "{ANON %d %s}" % (id(self), getattr(self, 'name', 'anon')) return self.__anon_label anon_label = property(anon_label) class ColumnCollection(util.OrderedProperties): """An ordered dictionary that stores a list of ColumnElement instances. Overrides the ``__eq__()`` method to produce SQL clauses between sets of correlated columns. """ def __init__(self, *cols): super(ColumnCollection, self).__init__() [self.add(c) for c in cols] def __str__(self): return repr([str(c) for c in self]) def replace(self, column): """add the given column to this collection, removing unaliased versions of this column as well as existing columns with the same key. e.g.:: t = Table('sometable', Column('col1', Integer)) t.replace_unalised(Column('col1', Integer, key='columnone')) will remove the original 'col1' from the collection, and add the new column under the name 'columnname'. Used by schema.Column to override columns during table reflection. """ if column.name in self and column.key != column.name: other = self[column.name] if other.name == other.key: del self[other.name] util.OrderedProperties.__setitem__(self, column.key, column) def add(self, column): """Add a column to this collection. The key attribute of the column will be used as the hash key for this dictionary. """ self[column.key] = column def __setitem__(self, key, value): if key in self: # this warning is primarily to catch select() statements which have conflicting # column names in their exported columns collection existing = self[key] if not existing.shares_lineage(value): table = getattr(existing, 'table', None) and existing.table.description util.warn(("Column %r on table %r being replaced by another " "column with the same key. Consider use_labels " "for select() statements.") % (key, table)) util.OrderedProperties.__setitem__(self, key, value) def remove(self, column): del self[column.key] def extend(self, iter): for c in iter: self.add(c) def __eq__(self, other): l = [] for c in other: for local in self: if c.shares_lineage(local): l.append(c==local) return and_(*l) def __contains__(self, other): if not isinstance(other, basestring): raise exceptions.ArgumentError("__contains__ requires a string argument") return util.OrderedProperties.__contains__(self, other) def contains_column(self, col): # have to use a Set here, because it will compare the identity # of the column, not just using "==" for comparison which will always return a # "True" value (i.e. a BinaryClause...) return col in util.Set(self) class ColumnSet(util.OrderedSet): def contains_column(self, col): return col in self def extend(self, cols): for col in cols: self.add(col) def __add__(self, other): return list(self) + list(other) def __eq__(self, other): l = [] for c in other: for local in self: if c.shares_lineage(local): l.append(c==local) return and_(*l) class Selectable(ClauseElement): """mark a class as being selectable""" class FromClause(Selectable): """Represent an element that can be used within the ``FROM`` clause of a ``SELECT`` statement.""" __visit_name__ = 'fromclause' named_with_column=False _hide_froms = [] def _get_from_objects(self, **modifiers): return [] def default_order_by(self): return [self.oid_column] def count(self, whereclause=None, **params): """return a SELECT COUNT generated against this ``FromClause``.""" if self.primary_key: col = list(self.primary_key)[0] else: col = list(self.columns)[0] return select([func.count(col).label('tbl_row_count')], whereclause, from_obj=[self], **params) def select(self, whereclause=None, **params): """return a SELECT of this ``FromClause``.""" return select([self], whereclause, **params) def join(self, right, onclause=None, isouter=False): """return a join of this ``FromClause`` against another ``FromClause``.""" return Join(self, right, onclause, isouter) def outerjoin(self, right, onclause=None): """return an outer join of this ``FromClause`` against another ``FromClause``.""" return Join(self, right, onclause, True) def alias(self, name=None): """return an alias of this ``FromClause`` against another ``FromClause``.""" return Alias(self, name) def is_derived_from(self, fromclause): """Return True if this FromClause is 'derived' from the given FromClause. An example would be an Alias of a Table is derived from that Table. """ return fromclause in util.Set(self._cloned_set) def replace_selectable(self, old, alias): """replace all occurences of FromClause 'old' with the given Alias object, returning a copy of this ``FromClause``.""" global ClauseAdapter if ClauseAdapter is None: from sqlalchemy.sql.util import ClauseAdapter return ClauseAdapter(alias).traverse(self, clone=True) def correspond_on_equivalents(self, column, equivalents): col = self.corresponding_column(column, require_embedded=True) if col is None and col in equivalents: for equiv in equivalents[col]: nc = self.corresponding_column(equiv, require_embedded=True) if nc: return nc return col def corresponding_column(self, column, require_embedded=False): """Given a ``ColumnElement``, return the exported ``ColumnElement`` object from this ``Selectable`` which corresponds to that original ``Column`` via a common anscestor column. column the target ``ColumnElement`` to be matched require_embedded only return corresponding columns for the given ``ColumnElement``, if the given ``ColumnElement`` is actually present within a sub-element of this ``FromClause``. Normally the column will match if it merely shares a common anscestor with one of the exported columns of this ``FromClause``. """ # dont dig around if the column is locally present if self.c.contains_column(column): return column col, intersect = None, None target_set = column.proxy_set cols = self.c if self.oid_column: cols += [self.oid_column] for c in cols: i = c.proxy_set.intersection(target_set) if i and \ (not require_embedded or c.proxy_set.issuperset(target_set)) and \ (intersect is None or len(i) > len(intersect)): col, intersect = c, i return col def description(self): """a brief description of this FromClause. Used primarily for error message formatting. """ return getattr(self, 'name', self.__class__.__name__ + " object") description = property(description) def _reset_exported(self): # delete all the "generated" collections of columns for a # newly cloned FromClause, so that they will be re-derived # from the item. this is because FromClause subclasses, when # cloned, need to reestablish new "proxied" columns that are # linked to the new item for attr in ('_columns', '_primary_key' '_foreign_keys', '_oid_column', '_embedded_columns', '_all_froms'): if hasattr(self, attr): delattr(self, attr) def _expr_attr_func(name): get = util.attrgetter(name) def attr(self): try: return get(self) except AttributeError: self._export_columns() return get(self) return property(attr) columns = c = _expr_attr_func('_columns') primary_key = _expr_attr_func('_primary_key') foreign_keys = _expr_attr_func('_foreign_keys') oid_column = _expr_attr_func('_oid_column') def _export_columns(self): """Initialize column collections.""" if hasattr(self, '_columns'): return self._columns = ColumnCollection() self._primary_key = ColumnSet() self._foreign_keys = util.Set() self._oid_column = None self._populate_column_collection() def _populate_column_collection(self): pass class _BindParamClause(ClauseElement, _CompareMixin): """Represent a bind parameter. Public constructor is the ``bindparam()`` function. """ __visit_name__ = 'bindparam' def __init__(self, key, value, type_=None, unique=False, isoutparam=False, shortname=None): """Construct a _BindParamClause. key the key for this bind param. Will be used in the generated SQL statement for dialects that use named parameters. This value may be modified when part of a compilation operation, if other ``_BindParamClause`` objects exist with the same key, or if its length is too long and truncation is required. value Initial value for this bind param. This value may be overridden by the dictionary of parameters sent to statement compilation/execution. shortname deprecated. type\_ A ``TypeEngine`` object that will be used to pre-process the value corresponding to this ``_BindParamClause`` at execution time. unique if True, the key name of this BindParamClause will be modified if another ``_BindParamClause`` of the same name already has been located within the containing ``ClauseElement``. isoutparam if True, the parameter should be treated like a stored procedure "OUT" parameter. """ if unique: self.key = "{ANON %d %s}" % (id(self), key or 'param') else: self.key = key or "{ANON %d param}" % id(self) self._orig_key = key or 'param' self.unique = unique self.value = value self.isoutparam = isoutparam self.shortname = shortname if type_ is None: self.type = sqltypes.type_map.get(type(value), sqltypes.NullType)() elif isinstance(type_, type): self.type = type_() else: self.type = type_ def _clone(self): c = ClauseElement._clone(self) if self.unique: c.key = "{ANON %d %s}" % (id(c), c._orig_key or 'param') return c def _convert_to_unique(self): if not self.unique: self.unique=True self.key = "{ANON %d %s}" % (id(self), self._orig_key or 'param') def _get_from_objects(self, **modifiers): return [] def bind_processor(self, dialect): return self.type.dialect_impl(dialect).bind_processor(dialect) def _compare_type(self, obj): if not isinstance(self.type, sqltypes.NullType): return self.type else: return obj.type def compare(self, other): """Compare this ``_BindParamClause`` to the given clause. Since ``compare()`` is meant to compare statement syntax, this method returns True if the two ``_BindParamClauses`` have just the same type. """ return isinstance(other, _BindParamClause) and other.type.__class__ == self.type.__class__ def __repr__(self): return "_BindParamClause(%s, %s, type_=%s)" % (repr(self.key), repr(self.value), repr(self.type)) class _TypeClause(ClauseElement): """Handle a type keyword in a SQL statement. Used by the ``Case`` statement. """ __visit_name__ = 'typeclause' def __init__(self, type): self.type = type def _get_from_objects(self, **modifiers): return [] class _TextClause(ClauseElement): """Represent a literal SQL text fragment. Public constructor is the ``text()`` function. """ __visit_name__ = 'textclause' _bind_params_regex = re.compile(r'(? RIGHT``.""" def __init__(self, left, right, operator, type_=None, negate=None, modifiers=None): ColumnElement.__init__(self) self.left = _literal_as_text(left).self_group(against=operator) self.right = _literal_as_text(right).self_group(against=operator) self.operator = operator self.type = sqltypes.to_instance(type_) self.negate = negate if modifiers is None: self.modifiers = {} else: self.modifiers = modifiers def _get_from_objects(self, **modifiers): return self.left._get_from_objects(**modifiers) + self.right._get_from_objects(**modifiers) def _copy_internals(self, clone=_clone): self.left = clone(self.left) self.right = clone(self.right) def get_children(self, **kwargs): return self.left, self.right def compare(self, other): """Compare this ``_BinaryExpression`` against the given ``_BinaryExpression``.""" return ( isinstance(other, _BinaryExpression) and self.operator == other.operator and ( self.left.compare(other.left) and self.right.compare(other.right) or ( operators.is_commutative(self.operator) and self.left.compare(other.right) and self.right.compare(other.left) ) ) ) def self_group(self, against=None): # use small/large defaults for comparison so that unknown # operators are always parenthesized if self.operator != against and operators.is_precedent(self.operator, against): return _Grouping(self) else: return self def _negate(self): if self.negate is not None: return _BinaryExpression(self.left, self.right, self.negate, negate=self.operator, type_=self.type, modifiers=self.modifiers) else: return super(_BinaryExpression, self)._negate() class _Exists(_UnaryExpression): __visit_name__ = _UnaryExpression.__visit_name__ def __init__(self, *args, **kwargs): kwargs['correlate'] = True s = select(*args, **kwargs).as_scalar().self_group() _UnaryExpression.__init__(self, s, operator=operators.exists) def select(self, whereclause=None, **params): return select([self], whereclause, **params) def correlate(self, fromclause): e = self._clone() e.element = self.element.correlate(fromclause).self_group() return e def where(self, clause): """return a new exists() construct with the given expression added to its WHERE clause, joined to the existing clause via AND, if any.""" e = self._clone() e.element = self.element.where(clause).self_group() return e class Join(FromClause): """represent a ``JOIN`` construct between two ``FromClause`` elements. The public constructor function for ``Join`` is the module-level ``join()`` function, as well as the ``join()`` method available off all ``FromClause`` subclasses. """ def __init__(self, left, right, onclause=None, isouter=False): self.left = _selectable(left) self.right = _selectable(right).self_group() if onclause is None: self.onclause = self.__match_primaries(self.left, self.right) else: self.onclause = onclause self.isouter = isouter self.__folded_equivalents = None def description(self): return "Join object on %s(%d) and %s(%d)" % (self.left.description, id(self.left), self.right.description, id(self.right)) description = property(description) def is_derived_from(self, fromclause): return fromclause is self or self.left.is_derived_from(fromclause) or self.right.is_derived_from(fromclause) def self_group(self, against=None): return _FromGrouping(self) def _populate_column_collection(self): columns = [c for c in self.left.columns] + [c for c in self.right.columns] global sql_util if not sql_util: from sqlalchemy.sql import util as sql_util self._primary_key.extend(sql_util.reduce_columns([c for c in columns if c.primary_key], self.onclause)) self._columns.update([(col._label, col) for col in columns]) self._foreign_keys.update(itertools.chain(*[col.foreign_keys for col in columns])) self._oid_column = self.left.oid_column def _copy_internals(self, clone=_clone): self._reset_exported() self.left = clone(self.left) self.right = clone(self.right) self.onclause = clone(self.onclause) self.__folded_equivalents = None def get_children(self, **kwargs): return self.left, self.right, self.onclause def __match_primaries(self, primary, secondary): global sql_util if not sql_util: from sqlalchemy.sql import util as sql_util return sql_util.join_condition(primary, secondary) def select(self, whereclause=None, fold_equivalents=False, **kwargs): """Create a ``Select`` from this ``Join``. whereclause the WHERE criterion that will be sent to the ``select()`` function fold_equivalents based on the join criterion of this ``Join``, do not include repeat column names in the column list of the resulting select, for columns that are calculated to be "equivalent" based on the join criterion of this ``Join``. This will recursively apply to any joins directly nested by this one as well. \**kwargs all other kwargs are sent to the underlying ``select()`` function. See the ``select()`` module level function for details. """ if fold_equivalents: global sql_util if not sql_util: from sqlalchemy.sql import util as sql_util collist = sql_util.folded_equivalents(self) else: collist = [self.left, self.right] return select(collist, whereclause, from_obj=[self], **kwargs) def bind(self): return self.left.bind or self.right.bind bind = property(bind) def alias(self, name=None): """Create a ``Select`` out of this ``Join`` clause and return an ``Alias`` of it. The ``Select`` is not correlating. """ return self.select(use_labels=True, correlate=False).alias(name) def _hide_froms(self): return itertools.chain(*[x.left._get_from_objects() + x.right._get_from_objects() for x in self._cloned_set]) _hide_froms = property(_hide_froms) def _get_from_objects(self, **modifiers): return [self] + self.onclause._get_from_objects(**modifiers) + self.left._get_from_objects(**modifiers) + self.right._get_from_objects(**modifiers) class Alias(FromClause): """Represents an table or selectable alias (AS). Represents an alias, as typically applied to any table or sub-select within a SQL statement using the ``AS`` keyword (or without the keyword on certain databases such as Oracle). This object is constructed from the ``alias()`` module level function as well as the ``alias()`` method available on all ``FromClause`` subclasses. """ named_with_column = True def __init__(self, selectable, alias=None): baseselectable = selectable while isinstance(baseselectable, Alias): baseselectable = baseselectable.selectable self.original = baseselectable self.selectable = selectable if alias is None: if self.original.named_with_column: alias = getattr(self.original, 'name', None) alias = '{ANON %d %s}' % (id(self), alias or 'anon') self.name = alias def description(self): return self.name.encode('ascii', 'backslashreplace') description = property(description) def is_derived_from(self, fromclause): if fromclause in util.Set(self._cloned_set): return True return self.selectable.is_derived_from(fromclause) def supports_execution(self): return self.original.supports_execution() def _table_iterator(self): return self.original._table_iterator() def _populate_column_collection(self): for col in self.selectable.columns: col._make_proxy(self) if self.selectable.oid_column is not None: self._oid_column = self.selectable.oid_column._make_proxy(self) def _copy_internals(self, clone=_clone): self._reset_exported() self.selectable = _clone(self.selectable) baseselectable = self.selectable while isinstance(baseselectable, Alias): baseselectable = baseselectable.selectable self.original = baseselectable def get_children(self, column_collections=True, aliased_selectables=True, **kwargs): if column_collections: for c in self.c: yield c if aliased_selectables: yield self.selectable def _get_from_objects(self, **modifiers): return [self] def bind(self): return self.selectable.bind bind = property(bind) class _ColumnElementAdapter(ColumnElement): """Adapts a ClauseElement which may or may not be a ColumnElement subclass itself into an object which acts like a ColumnElement. """ def __init__(self, elem): self.elem = elem self.type = getattr(elem, 'type', None) def key(self): return self.elem.key key = property(key) def _label(self): try: return self.elem._label except AttributeError: return self.anon_label _label = property(_label) def _copy_internals(self, clone=_clone): self.elem = clone(self.elem) def get_children(self, **kwargs): return self.elem, def _get_from_objects(self, **modifiers): return self.elem._get_from_objects(**modifiers) def __getattr__(self, attr): return getattr(self.elem, attr) def __getstate__(self): return {'elem':self.elem, 'type':self.type} def __setstate__(self, state): self.elem = state['elem'] self.type = state['type'] class _Grouping(_ColumnElementAdapter): """Represent a grouping within a column expression""" pass class _FromGrouping(FromClause): """Represent a grouping of a FROM clause""" __visit_name__ = 'grouping' def __init__(self, elem): self.elem = elem def columns(self): return self.elem.columns columns = c = property(columns) def _hide_froms(self): return self.elem._hide_froms _hide_froms = property(_hide_froms) def get_children(self, **kwargs): return self.elem, def _copy_internals(self, clone=_clone): self.elem = clone(self.elem) def _get_from_objects(self, **modifiers): return self.elem._get_from_objects(**modifiers) def __getattr__(self, attr): return getattr(self.elem, attr) class _Label(ColumnElement): """Represents a column label (AS). Represent a label, as typically applied to any column-level element using the ``AS`` sql keyword. This object is constructed from the ``label()`` module level function as well as the ``label()`` method available on all ``ColumnElement`` subclasses. """ def __init__(self, name, obj, type_=None): while isinstance(obj, _Label): obj = obj.obj self.name = name or "{ANON %d %s}" % (id(self), getattr(obj, 'name', 'anon')) self.obj = obj.self_group(against=operators.as_) self.type = sqltypes.to_instance(type_ or getattr(obj, 'type', None)) def key(self): return self.name key = property(key) def _label(self): return self.name _label = property(_label) def _proxy_attr(name): def attr(self): return getattr(self.obj, name) return property(attr) proxies = _proxy_attr('proxies') base_columns = _proxy_attr('base_columns') proxy_set = _proxy_attr('proxy_set') primary_key = _proxy_attr('primary_key') foreign_keys = _proxy_attr('foreign_keys') def expression_element(self): return self.obj def get_children(self, **kwargs): return self.obj, def _copy_internals(self, clone=_clone): self.obj = clone(self.obj) def _get_from_objects(self, **modifiers): return self.obj._get_from_objects(**modifiers) def _make_proxy(self, selectable, name = None): if isinstance(self.obj, (Selectable, ColumnElement)): e = self.obj._make_proxy(selectable, name=self.name) else: e = column(self.name)._make_proxy(selectable=selectable) e.proxies.append(self) return e class _ColumnClause(ColumnElement): """Represents a generic column expression from any textual string. This includes columns associated with tables, aliases and select statements, but also any arbitrary text. May or may not be bound to an underlying ``Selectable``. ``_ColumnClause`` is usually created publically via the ``column()`` function or the ``literal_column()`` function. text the text of the element. selectable parent selectable. type ``TypeEngine`` object which can associate this ``_ColumnClause`` with a type. is_literal if True, the ``_ColumnClause`` is assumed to be an exact expression that will be delivered to the output with no quoting rules applied regardless of case sensitive settings. the ``literal_column()`` function is usually used to create such a ``_ColumnClause``. """ def __init__(self, text, selectable=None, type_=None, _is_oid=False, is_literal=False): ColumnElement.__init__(self) self.key = self.name = text self.table = selectable self.type = sqltypes.to_instance(type_) self._is_oid = _is_oid self.__label = None self.is_literal = is_literal def description(self): return self.name.encode('ascii', 'backslashreplace') description = property(description) def _clone(self): # ColumnClause is immutable return self def _label(self): """Generate a 'label' string for this column. """ # for a "literal" column, we've no idea what the text is # therefore no 'label' can be automatically generated if self.is_literal: return None if not self.__label: if self.table and self.table.named_with_column: if getattr(self.table, 'schema', None): self.__label = self.table.schema + "_" + self.table.name + "_" + self.name else: self.__label = self.table.name + "_" + self.name if self.__label in self.table.c: label = self.__label counter = 1 while label in self.table.c: label = self.__label + "_" + str(counter) counter +=1 self.__label = label else: self.__label = self.name return self.__label _label = property(_label) def label(self, name): # if going off the "__label" property and its None, we have # no label; return self if name is None: return self else: return super(_ColumnClause, self).label(name) def _get_from_objects(self, **modifiers): if self.table is not None: return [self.table] else: return [] def _bind_param(self, obj): return _BindParamClause(self.name, obj, type_=self.type, unique=True) def _make_proxy(self, selectable, name = None): # propagate the "is_literal" flag only if we are keeping our name, # otherwise its considered to be a label is_literal = self.is_literal and (name is None or name == self.name) c = _ColumnClause(name or self.name, selectable=selectable, _is_oid=self._is_oid, type_=self.type, is_literal=is_literal) c.proxies = [self] if not self._is_oid: selectable.columns[c.name] = c return c def _compare_type(self, obj): return self.type class TableClause(FromClause): """Represents a "table" construct. Note that this represents tables only as another syntactical construct within SQL expressions; it does not provide schema-level functionality. """ named_with_column = True def __init__(self, name, *columns): super(TableClause, self).__init__() self.name = self.fullname = name self._oid_column = _ColumnClause('oid', self, _is_oid=True) self._columns = ColumnCollection() self._primary_key = ColumnSet() self._foreign_keys = util.Set() for c in columns: self.append_column(c) def _export_columns(self): raise NotImplementedError() def description(self): return self.name.encode('ascii', 'backslashreplace') description = property(description) def _clone(self): # TableClause is immutable return self def append_column(self, c): self._columns[c.name] = c c.table = self def get_children(self, column_collections=True, **kwargs): if column_collections: return [c for c in self.c] else: return [] def count(self, whereclause=None, **params): if self.primary_key: col = list(self.primary_key)[0] else: col = list(self.columns)[0] return select([func.count(col).label('tbl_row_count')], whereclause, from_obj=[self], **params) def insert(self, values=None, inline=False, **kwargs): return insert(self, values=values, inline=inline, **kwargs) def update(self, whereclause=None, values=None, inline=False, **kwargs): return update(self, whereclause=whereclause, values=values, inline=inline, **kwargs) def delete(self, whereclause=None): return delete(self, whereclause) def _get_from_objects(self, **modifiers): return [self] class _SelectBaseMixin(object): """Base class for ``Select`` and ``CompoundSelects``.""" def __init__(self, use_labels=False, for_update=False, limit=None, offset=None, order_by=None, group_by=None, bind=None, autocommit=False): self.use_labels = use_labels self.for_update = for_update self._autocommit = autocommit self._limit = limit self._offset = offset self._bind = bind self._order_by_clause = ClauseList(*util.to_list(order_by, [])) self._group_by_clause = ClauseList(*util.to_list(group_by, [])) def as_scalar(self): """return a 'scalar' representation of this selectable, which can be used as a column expression. Typically, a select statement which has only one column in its columns clause is eligible to be used as a scalar expression. The returned object is an instance of [sqlalchemy.sql.expression#_ScalarSelect]. """ return _ScalarSelect(self) def apply_labels(self): """return a new selectable with the 'use_labels' flag set to True. This will result in column expressions being generated using labels against their table name, such as "SELECT somecolumn AS tablename_somecolumn". This allows selectables which contain multiple FROM clauses to produce a unique set of column names regardless of name conflicts among the individual FROM clauses. """ s = self._generate() s.use_labels = True return s def label(self, name): """return a 'scalar' representation of this selectable, embedded as a subquery with a label. See also ``as_scalar()``. """ return self.as_scalar().label(name) def supports_execution(self): """part of the ClauseElement contract; returns ``True`` in all cases for this class.""" return True def autocommit(self): """return a new selectable with the 'autocommit' flag set to True.""" s = self._generate() s._autocommit = True return s def _generate(self): s = self.__class__.__new__(self.__class__) s.__dict__ = self.__dict__.copy() s._reset_exported() return s def limit(self, limit): """return a new selectable with the given LIMIT criterion applied.""" s = self._generate() s._limit = limit return s def offset(self, offset): """return a new selectable with the given OFFSET criterion applied.""" s = self._generate() s._offset = offset return s def order_by(self, *clauses): """return a new selectable with the given list of ORDER BY criterion applied. The criterion will be appended to any pre-existing ORDER BY criterion. """ s = self._generate() s.append_order_by(*clauses) return s def group_by(self, *clauses): """return a new selectable with the given list of GROUP BY criterion applied. The criterion will be appended to any pre-existing GROUP BY criterion. """ s = self._generate() s.append_group_by(*clauses) return s def append_order_by(self, *clauses): """Append the given ORDER BY criterion applied to this selectable. The criterion will be appended to any pre-existing ORDER BY criterion. """ if len(clauses) == 1 and clauses[0] is None: self._order_by_clause = ClauseList() else: if getattr(self, '_order_by_clause', None): clauses = list(self._order_by_clause) + list(clauses) self._order_by_clause = ClauseList(*clauses) def append_group_by(self, *clauses): """Append the given GROUP BY criterion applied to this selectable. The criterion will be appended to any pre-existing GROUP BY criterion. """ if len(clauses) == 1 and clauses[0] is None: self._group_by_clause = ClauseList() else: if getattr(self, '_group_by_clause', None): clauses = list(self._group_by_clause) + list(clauses) self._group_by_clause = ClauseList(*clauses) def _get_from_objects(self, is_where=False, **modifiers): if is_where: return [] else: return [self] class _ScalarSelect(_Grouping): __visit_name__ = 'grouping' def __init__(self, elem): self.elem = elem cols = list(elem.c) if len(cols) != 1: raise exceptions.InvalidRequestError("Scalar select can only be created from a Select object that has exactly one column expression.") self.type = cols[0].type def columns(self): raise exceptions.InvalidRequestError("Scalar Select expression has no columns; use this object directly within a column-level expression.") columns = c = property(columns) def self_group(self, **kwargs): return self def _make_proxy(self, selectable, name): return list(self.inner_columns)[0]._make_proxy(selectable, name) def _get_from_objects(self, **modifiers): return [] class CompoundSelect(_SelectBaseMixin, FromClause): def __init__(self, keyword, *selects, **kwargs): self._should_correlate = kwargs.pop('correlate', False) self.keyword = keyword self.selects = [] numcols = None # some DBs do not like ORDER BY in the inner queries of a UNION, etc. for n, s in enumerate(selects): if not numcols: numcols = len(s.c) elif len(s.c) != numcols: raise exceptions.ArgumentError("All selectables passed to CompoundSelect must have identical numbers of columns; select #%d has %d columns, select #%d has %d" % (1, len(self.selects[0].c), n+1, len(s.c)) ) if s._order_by_clause: s = s.order_by(None) # unions group from left to right, so don't group first select if n: self.selects.append(s.self_group(self)) else: self.selects.append(s) _SelectBaseMixin.__init__(self, **kwargs) def self_group(self, against=None): return _FromGrouping(self) def _populate_column_collection(self): for cols in zip(*[s.c for s in self.selects]): proxy = cols[0]._make_proxy(self, name=self.use_labels and cols[0]._label or None) proxy.proxies = cols oid_proxies = [ c for c in [f.oid_column for f in self.selects] if c is not None ] if oid_proxies: col = oid_proxies[0]._make_proxy(self) col.proxies = oid_proxies self._oid_column = col def _copy_internals(self, clone=_clone): self._reset_exported() self.selects = [clone(s) for s in self.selects] if hasattr(self, '_col_map'): del self._col_map for attr in ('_order_by_clause', '_group_by_clause'): if getattr(self, attr) is not None: setattr(self, attr, clone(getattr(self, attr))) def get_children(self, column_collections=True, **kwargs): return (column_collections and list(self.c) or []) + \ [self._order_by_clause, self._group_by_clause] + list(self.selects) def _table_iterator(self): for s in self.selects: for t in s._table_iterator(): yield t def bind(self): if self._bind: return self._bind for s in self.selects: e = s.bind if e: return e else: return None def _set_bind(self, bind): self._bind = bind bind = property(bind, _set_bind) class Select(_SelectBaseMixin, FromClause): """Represents a ``SELECT`` statement. Select statements support appendable clauses, as well as the ability to execute themselves and return a result set. """ def __init__(self, columns, whereclause=None, from_obj=None, distinct=False, having=None, correlate=True, prefixes=None, **kwargs): """Construct a Select object. The public constructor for Select is the [sqlalchemy.sql.expression#select()] function; see that function for argument descriptions. Additional generative and mutator methods are available on the [sqlalchemy.sql.expression#_SelectBaseMixin] superclass. """ self._should_correlate = correlate self._distinct = distinct self._correlate = util.Set() if columns: self._raw_columns = [ isinstance(c, _ScalarSelect) and c.self_group(against=operators.comma_op) or c for c in [_literal_as_column(c) for c in columns] ] else: self._raw_columns = [] if from_obj: self._froms = util.Set([ _is_literal(f) and _TextClause(f) or f for f in util.to_list(from_obj) ]) else: self._froms = util.Set() if whereclause: self._whereclause = _literal_as_text(whereclause) else: self._whereclause = None if having: self._having = _literal_as_text(having) else: self._having = None if prefixes: self._prefixes = [_literal_as_text(p) for p in prefixes] else: self._prefixes = [] _SelectBaseMixin.__init__(self, **kwargs) def _get_display_froms(self, existing_froms=None): """Return the full list of 'from' clauses to be displayed. Takes into account a set of existing froms which may be rendered in the FROM clause of enclosing selects; this Select may want to leave those absent if it is automatically correlating. """ froms = util.OrderedSet() for col in self._raw_columns: froms.update(col._get_from_objects()) if self._whereclause is not None: froms.update(self._whereclause._get_from_objects(is_where=True)) if self._froms: froms.update(self._froms) toremove = itertools.chain(*[f._hide_froms for f in froms]) froms.difference_update(toremove) if len(froms) > 1 or self._correlate: if self._correlate: froms.difference_update(_cloned_intersection(froms, self._correlate)) if self._should_correlate and existing_froms: froms.difference_update(_cloned_intersection(froms, existing_froms)) if not len(froms): raise exceptions.InvalidRequestError("Select statement '%s' returned no FROM clauses due to auto-correlation; specify correlate() to control correlation manually." % self) return froms froms = property(_get_display_froms, doc="""Return a list of all FromClause elements which will be applied to the FROM clause of the resulting statement.""") def type(self): raise exceptions.InvalidRequestError("Select objects don't have a type. Call as_scalar() on this Select object to return a 'scalar' version of this Select.") type = property(type) def locate_all_froms(self): """return a Set of all FromClause elements referenced by this Select. This set is a superset of that returned by the ``froms`` property, which is specifically for those FromClause elements that would actually be rendered. """ if hasattr(self, '_all_froms'): return self._all_froms froms = util.Set( itertools.chain(* [self._froms] + [f._get_from_objects() for f in self._froms] + [col._get_from_objects() for col in self._raw_columns] ) ) if self._whereclause: froms.update(self._whereclause._get_from_objects(is_where=True)) self._all_froms = froms return froms def inner_columns(self): """an iteratorof all ColumnElement expressions which would be rendered into the columns clause of the resulting SELECT statement. """ for c in self._raw_columns: if isinstance(c, Selectable): for co in c.columns: yield co else: yield c inner_columns = property(inner_columns) def is_derived_from(self, fromclause): if self in util.Set(fromclause._cloned_set): return True for f in self.locate_all_froms(): if f.is_derived_from(fromclause): return True return False def _copy_internals(self, clone=_clone): self._reset_exported() from_cloned = dict([(f, clone(f)) for f in self._froms.union(self._correlate)]) self._froms = util.Set([from_cloned[f] for f in self._froms]) self._correlate = util.Set([from_cloned[f] for f in self._correlate]) self._raw_columns = [clone(c) for c in self._raw_columns] for attr in ('_whereclause', '_having', '_order_by_clause', '_group_by_clause'): if getattr(self, attr) is not None: setattr(self, attr, clone(getattr(self, attr))) def get_children(self, column_collections=True, **kwargs): """return child elements as per the ClauseElement specification.""" return (column_collections and list(self.columns) or []) + \ list(self.locate_all_froms()) + \ [x for x in (self._whereclause, self._having, self._order_by_clause, self._group_by_clause) if x is not None] def column(self, column): """return a new select() construct with the given column expression added to its columns clause.""" s = self._generate() column = _literal_as_column(column) if isinstance(column, _ScalarSelect): column = column.self_group(against=operators.comma_op) s._raw_columns = s._raw_columns + [column] return s def where(self, whereclause): """return a new select() construct with the given expression added to its WHERE clause, joined to the existing clause via AND, if any.""" s = self._generate() s.append_whereclause(whereclause) return s def having(self, having): """return a new select() construct with the given expression added to its HAVING clause, joined to the existing clause via AND, if any.""" s = self._generate() s.append_having(having) return s def distinct(self): """return a new select() construct which will apply DISTINCT to its columns clause.""" s = self._generate() s._distinct = True return s def prefix_with(self, clause): """return a new select() construct which will apply the given expression to the start of its columns clause, not using any commas.""" s = self._generate() clause = _literal_as_text(clause) s._prefixes = s._prefixes + [clause] return s def select_from(self, fromclause): """return a new select() construct with the given FROM expression applied to its list of FROM objects.""" s = self._generate() if _is_literal(fromclause): fromclause = _TextClause(fromclause) s._froms = s._froms.union([fromclause]) return s def correlate(self, *fromclauses): """return a new select() construct which will correlate the given FROM clauses to that of an enclosing select(), if a match is found. By "match", the given fromclause must be present in this select's list of FROM objects and also present in an enclosing select's list of FROM objects. Calling this method turns off the select's default behavior of "auto-correlation". Normally, select() auto-correlates all of its FROM clauses to those of an embedded select when compiled. If the fromclause is None, correlation is disabled for the returned select(). """ s = self._generate() s._should_correlate=False if fromclauses == (None,): s._correlate = util.Set() else: s._correlate = s._correlate.union(fromclauses) return s def append_correlation(self, fromclause): """append the given correlation expression to this select() construct.""" self._should_correlate=False self._correlate = self._correlate.union([fromclause]) def append_column(self, column): """append the given column expression to the columns clause of this select() construct.""" column = _literal_as_column(column) if isinstance(column, _ScalarSelect): column = column.self_group(against=operators.comma_op) self._raw_columns = self._raw_columns + [column] self._reset_exported() def append_prefix(self, clause): """append the given columns clause prefix expression to this select() construct.""" clause = _literal_as_text(clause) self._prefixes = self._prefixes.union([clause]) def append_whereclause(self, whereclause): """append the given expression to this select() construct's WHERE criterion. The expression will be joined to existing WHERE criterion via AND. """ if self._whereclause is not None: self._whereclause = and_(self._whereclause, _literal_as_text(whereclause)) else: self._whereclause = _literal_as_text(whereclause) def append_having(self, having): """append the given expression to this select() construct's HAVING criterion. The expression will be joined to existing HAVING criterion via AND. """ if self._having is not None: self._having = and_(self._having, _literal_as_text(having)) else: self._having = _literal_as_text(having) def append_from(self, fromclause): """append the given FromClause expression to this select() construct's FROM clause. """ if _is_literal(fromclause): fromclause = _TextClause(fromclause) self._froms = self._froms.union([fromclause]) def __exportable_columns(self): for column in self._raw_columns: if isinstance(column, Selectable): for co in column.columns: yield co elif isinstance(column, ColumnElement): yield column else: continue def _populate_column_collection(self): for c in self.__exportable_columns(): c._make_proxy(self, name=self.use_labels and c._label or None) oid_proxies = [c for c in [f.oid_column for f in self.locate_all_froms() if f is not self] if c is not None ] if oid_proxies: col = oid_proxies[0]._make_proxy(self) col.proxies = oid_proxies self._oid_column = col def self_group(self, against=None): """return a 'grouping' construct as per the ClauseElement specification. This produces an element that can be embedded in an expression. Note that this method is called automatically as needed when constructing expressions. """ if isinstance(against, CompoundSelect): return self return _FromGrouping(self) def union(self, other, **kwargs): """return a SQL UNION of this select() construct against the given selectable.""" return union(self, other, **kwargs) def union_all(self, other, **kwargs): """return a SQL UNION ALL of this select() construct against the given selectable.""" return union_all(self, other, **kwargs) def except_(self, other, **kwargs): """return a SQL EXCEPT of this select() construct against the given selectable.""" return except_(self, other, **kwargs) def except_all(self, other, **kwargs): """return a SQL EXCEPT ALL of this select() construct against the given selectable.""" return except_all(self, other, **kwargs) def intersect(self, other, **kwargs): """return a SQL INTERSECT of this select() construct against the given selectable.""" return intersect(self, other, **kwargs) def intersect_all(self, other, **kwargs): """return a SQL INTERSECT ALL of this select() construct against the given selectable.""" return intersect_all(self, other, **kwargs) def _table_iterator(self): for t in visitors.NoColumnVisitor().iterate(self): if isinstance(t, TableClause): yield t def bind(self): if self._bind: return self._bind for f in self._froms: if f is self: continue e = f.bind if e: self._bind = e return e # look through the columns (largely synomous with looking # through the FROMs except in the case of _CalculatedClause/_Function) for c in self._raw_columns: if getattr(c, 'table', None) is self: continue e = c.bind if e: self._bind = e return e return None def _set_bind(self, bind): self._bind = bind bind = property(bind, _set_bind) class _UpdateBase(ClauseElement): """Form the base for ``INSERT``, ``UPDATE``, and ``DELETE`` statements.""" def supports_execution(self): return True def _table_iterator(self): return iter([self.table]) def _generate(self): s = self.__class__.__new__(self.__class__) s.__dict__ = self.__dict__.copy() return s def _process_colparams(self, parameters): if parameters is None: return None if isinstance(parameters, (list, tuple)): pp = {} for i, c in enumerate(self.table.c): pp[c.key] = parameters[i] return pp else: return parameters def bind(self): return self._bind or self.table.bind def _set_bind(self, bind): self._bind = bind bind = property(bind, _set_bind) class _ValuesBase(_UpdateBase): def values(self, *args, **kwargs): """specify the VALUES clause for an INSERT statement, or the SET clause for an UPDATE. \**kwargs key= arguments \*args deprecated. A single dictionary can be sent as the first positional argument. """ if args: v = args[0] else: v = {} if len(v) == 0 and len(kwargs) == 0: return self u = self._clone() if u.parameters is None: u.parameters = u._process_colparams(v) u.parameters.update(kwargs) else: u.parameters = self.parameters.copy() u.parameters.update(u._process_colparams(v)) u.parameters.update(kwargs) return u class Insert(_ValuesBase): def __init__(self, table, values=None, inline=False, bind=None, prefixes=None, **kwargs): self._bind = bind self.table = table self.select = None self.inline=inline if prefixes: self._prefixes = [_literal_as_text(p) for p in prefixes] else: self._prefixes = [] self.parameters = self._process_colparams(values) self.kwargs = kwargs def get_children(self, **kwargs): if self.select is not None: return self.select, else: return () def _copy_internals(self, clone=_clone): self.parameters = self.parameters.copy() def prefix_with(self, clause): """Add a word or expression between INSERT and INTO. Generative. If multiple prefixes are supplied, they will be separated with spaces. """ gen = self._generate() clause = _literal_as_text(clause) gen._prefixes = self._prefixes + [clause] return gen class Update(_ValuesBase): def __init__(self, table, whereclause, values=None, inline=False, bind=None, **kwargs): self._bind = bind self.table = table if whereclause: self._whereclause = _literal_as_text(whereclause) else: self._whereclause = None self.inline = inline self.parameters = self._process_colparams(values) self.kwargs = kwargs def get_children(self, **kwargs): if self._whereclause is not None: return self._whereclause, else: return () def _copy_internals(self, clone=_clone): self._whereclause = clone(self._whereclause) self.parameters = self.parameters.copy() def where(self, whereclause): """return a new update() construct with the given expression added to its WHERE clause, joined to the existing clause via AND, if any.""" s = self._generate() if s._whereclause is not None: s._whereclause = and_(s._whereclause, _literal_as_text(whereclause)) else: s._whereclause = _literal_as_text(whereclause) return s class Delete(_UpdateBase): def __init__(self, table, whereclause, bind=None): self._bind = bind self.table = table if whereclause: self._whereclause = _literal_as_text(whereclause) else: self._whereclause = None def get_children(self, **kwargs): if self._whereclause is not None: return self._whereclause, else: return () def where(self, whereclause): """return a new delete() construct with the given expression added to its WHERE clause, joined to the existing clause via AND, if any.""" s = self._generate() if s._whereclause is not None: s._whereclause = and_(s._whereclause, _literal_as_text(whereclause)) else: s._whereclause = _literal_as_text(whereclause) return s def _copy_internals(self, clone=_clone): self._whereclause = clone(self._whereclause) class _IdentifiedClause(ClauseElement): def __init__(self, ident): self.ident = ident def supports_execution(self): return True class SavepointClause(_IdentifiedClause): pass class RollbackToSavepointClause(_IdentifiedClause): pass class ReleaseSavepointClause(_IdentifiedClause): pass