diff options
Diffstat (limited to 'lib/sqlalchemy/sql/selectable.py')
| -rw-r--r-- | lib/sqlalchemy/sql/selectable.py | 172 |
1 files changed, 110 insertions, 62 deletions
diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py index 8198a6733..f848ef6db 100644 --- a/lib/sqlalchemy/sql/selectable.py +++ b/lib/sqlalchemy/sql/selectable.py @@ -1,5 +1,5 @@ # sql/selectable.py -# Copyright (C) 2005-2014 the SQLAlchemy authors and contributors +# Copyright (C) 2005-2015 the SQLAlchemy authors and contributors # <see AUTHORS file> # # This module is part of SQLAlchemy and is released under @@ -43,9 +43,10 @@ def _interpret_as_from(element): {"expr": util.ellipses_string(element)}) return TextClause(util.text_type(element)) - elif hasattr(insp, "selectable"): + try: return insp.selectable - raise exc.ArgumentError("FROM expression expected") + except AttributeError: + raise exc.ArgumentError("FROM expression expected") def _interpret_as_select(element): @@ -171,6 +172,79 @@ class Selectable(ClauseElement): return self +class HasPrefixes(object): + _prefixes = () + + @_generative + def prefix_with(self, *expr, **kw): + """Add one or more expressions following the statement keyword, i.e. + SELECT, INSERT, UPDATE, or DELETE. Generative. + + This is used to support backend-specific prefix keywords such as those + provided by MySQL. + + E.g.:: + + stmt = table.insert().prefix_with("LOW_PRIORITY", dialect="mysql") + + Multiple prefixes can be specified by multiple calls + to :meth:`.prefix_with`. + + :param \*expr: textual or :class:`.ClauseElement` construct which + will be rendered following the INSERT, UPDATE, or DELETE + keyword. + :param \**kw: A single keyword 'dialect' is accepted. This is an + optional string dialect name which will + limit rendering of this prefix to only that dialect. + + """ + dialect = kw.pop('dialect', None) + if kw: + raise exc.ArgumentError("Unsupported argument(s): %s" % + ",".join(kw)) + self._setup_prefixes(expr, dialect) + + def _setup_prefixes(self, prefixes, dialect=None): + self._prefixes = self._prefixes + tuple( + [(_literal_as_text(p, warn=False), dialect) for p in prefixes]) + + +class HasSuffixes(object): + _suffixes = () + + @_generative + def suffix_with(self, *expr, **kw): + """Add one or more expressions following the statement as a whole. + + This is used to support backend-specific suffix keywords on + certain constructs. + + E.g.:: + + stmt = select([col1, col2]).cte().suffix_with( + "cycle empno set y_cycle to 1 default 0", dialect="oracle") + + Multiple prefixes can be specified by multiple calls + to :meth:`.suffix_with`. + + :param \*expr: textual or :class:`.ClauseElement` construct which + will be rendered following the target clause. + :param \**kw: A single keyword 'dialect' is accepted. This is an + optional string dialect name which will + limit rendering of this suffix to only that dialect. + + """ + dialect = kw.pop('dialect', None) + if kw: + raise exc.ArgumentError("Unsupported argument(s): %s" % + ",".join(kw)) + self._setup_suffixes(expr, dialect) + + def _setup_suffixes(self, suffixes, dialect=None): + self._suffixes = self._suffixes + tuple( + [(_literal_as_text(p, warn=False), dialect) for p in suffixes]) + + class FromClause(Selectable): """Represent an element that can be used within the ``FROM`` clause of a ``SELECT`` statement. @@ -874,7 +948,7 @@ class Join(FromClause): """return an alias of this :class:`.Join`. The default behavior here is to first produce a SELECT - construct from this :class:`.Join`, then to produce a + construct from this :class:`.Join`, then to produce an :class:`.Alias` from that. So given a join of the form:: j = table_a.join(table_b, table_a.c.id == table_b.c.a_id) @@ -1088,7 +1162,7 @@ class Alias(FromClause): return self.element.bind -class CTE(Alias): +class CTE(Generative, HasSuffixes, Alias): """Represent a Common Table Expression. The :class:`.CTE` object is obtained using the @@ -1104,10 +1178,13 @@ class CTE(Alias): name=None, recursive=False, _cte_alias=None, - _restates=frozenset()): + _restates=frozenset(), + _suffixes=None): self.recursive = recursive self._cte_alias = _cte_alias self._restates = _restates + if _suffixes: + self._suffixes = _suffixes super(CTE, self).__init__(selectable, name=name) def alias(self, name=None, flat=False): @@ -1116,6 +1193,7 @@ class CTE(Alias): name=name, recursive=self.recursive, _cte_alias=self, + _suffixes=self._suffixes ) def union(self, other): @@ -1123,7 +1201,8 @@ class CTE(Alias): self.original.union(other), name=self.name, recursive=self.recursive, - _restates=self._restates.union([self]) + _restates=self._restates.union([self]), + _suffixes=self._suffixes ) def union_all(self, other): @@ -1131,7 +1210,8 @@ class CTE(Alias): self.original.union_all(other), name=self.name, recursive=self.recursive, - _restates=self._restates.union([self]) + _restates=self._restates.union([self]), + _suffixes=self._suffixes ) @@ -2118,44 +2198,7 @@ class CompoundSelect(GenerativeSelect): bind = property(bind, _set_bind) -class HasPrefixes(object): - _prefixes = () - - @_generative - def prefix_with(self, *expr, **kw): - """Add one or more expressions following the statement keyword, i.e. - SELECT, INSERT, UPDATE, or DELETE. Generative. - - This is used to support backend-specific prefix keywords such as those - provided by MySQL. - - E.g.:: - - stmt = table.insert().prefix_with("LOW_PRIORITY", dialect="mysql") - - Multiple prefixes can be specified by multiple calls - to :meth:`.prefix_with`. - - :param \*expr: textual or :class:`.ClauseElement` construct which - will be rendered following the INSERT, UPDATE, or DELETE - keyword. - :param \**kw: A single keyword 'dialect' is accepted. This is an - optional string dialect name which will - limit rendering of this prefix to only that dialect. - - """ - dialect = kw.pop('dialect', None) - if kw: - raise exc.ArgumentError("Unsupported argument(s): %s" % - ",".join(kw)) - self._setup_prefixes(expr, dialect) - - def _setup_prefixes(self, prefixes, dialect=None): - self._prefixes = self._prefixes + tuple( - [(_literal_as_text(p, warn=False), dialect) for p in prefixes]) - - -class Select(HasPrefixes, GenerativeSelect): +class Select(HasPrefixes, HasSuffixes, GenerativeSelect): """Represents a ``SELECT`` statement. """ @@ -2163,6 +2206,7 @@ class Select(HasPrefixes, GenerativeSelect): __visit_name__ = 'select' _prefixes = () + _suffixes = () _hints = util.immutabledict() _statement_hints = () _distinct = False @@ -2180,6 +2224,7 @@ class Select(HasPrefixes, GenerativeSelect): having=None, correlate=True, prefixes=None, + suffixes=None, **kwargs): """Construct a new :class:`.Select`. @@ -2425,6 +2470,9 @@ class Select(HasPrefixes, GenerativeSelect): if prefixes: self._setup_prefixes(prefixes) + if suffixes: + self._setup_suffixes(suffixes) + GenerativeSelect.__init__(self, **kwargs) @property @@ -2437,21 +2485,20 @@ class Select(HasPrefixes, GenerativeSelect): seen = set() translate = self._from_cloned - def add(items): - for item in items: - if item is self: - raise exc.InvalidRequestError( - "select() construct refers to itself as a FROM") - if translate and item in translate: - item = translate[item] - if not seen.intersection(item._cloned_set): - froms.append(item) - seen.update(item._cloned_set) - - add(_from_objects(*self._raw_columns)) - if self._whereclause is not None: - add(_from_objects(self._whereclause)) - add(self._from_obj) + for item in itertools.chain( + _from_objects(*self._raw_columns), + _from_objects(self._whereclause) + if self._whereclause is not None else (), + self._from_obj + ): + if item is self: + raise exc.InvalidRequestError( + "select() construct refers to itself as a FROM") + if translate and item in translate: + item = translate[item] + if not seen.intersection(item._cloned_set): + froms.append(item) + seen.update(item._cloned_set) return froms @@ -2633,7 +2680,8 @@ class Select(HasPrefixes, GenerativeSelect): only_froms = dict( (c.key, c) for c in _select_iterables(self.froms) if c._allow_label_resolve) - with_cols.update(only_froms) + for key, value in only_froms.items(): + with_cols.setdefault(key, value) return with_cols, only_froms |