diff options
Diffstat (limited to 'lib/sqlalchemy/sql')
| -rw-r--r-- | lib/sqlalchemy/sql/expression.py | 9 | ||||
| -rw-r--r-- | lib/sqlalchemy/sql/util.py | 83 | ||||
| -rw-r--r-- | lib/sqlalchemy/sql/visitors.py | 37 |
3 files changed, 65 insertions, 64 deletions
diff --git a/lib/sqlalchemy/sql/expression.py b/lib/sqlalchemy/sql/expression.py index f4611de6d..3d95948cb 100644 --- a/lib/sqlalchemy/sql/expression.py +++ b/lib/sqlalchemy/sql/expression.py @@ -1621,6 +1621,15 @@ class FromClause(Selectable): 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 diff --git a/lib/sqlalchemy/sql/util.py b/lib/sqlalchemy/sql/util.py index d4163b73b..8ed561e5f 100644 --- a/lib/sqlalchemy/sql/util.py +++ b/lib/sqlalchemy/sql/util.py @@ -93,46 +93,51 @@ def reduce_columns(columns, *clauses): return expression.ColumnSet(columns.difference(omit)) -def row_adapter(from_, to, equivalent_columns=None): - """create a row adapter between two selectables. +class AliasedRow(object): + + def __init__(self, row, map): + # AliasedRow objects don't nest, so un-nest + # if another AliasedRow was passed + if isinstance(row, AliasedRow): + self.row = row.row + else: + self.row = row + self.map = map + + def __contains__(self, key): + return self.map[key] in self.row - The returned adapter is a class that can be instantiated repeatedly for any number - of rows; this is an inexpensive process. However, the creation of the row - adapter class itself *is* fairly expensive so caching should be used to prevent - repeated calls to this function. - """ + def has_key(self, key): + return key in self - map = {} - for c in to.c: - corr = from_.corresponding_column(c) - if corr: - map[c] = corr - elif equivalent_columns: - if c in equivalent_columns: - for c2 in equivalent_columns[c]: - corr = from_.corresponding_column(c2) - if corr: - map[c] = corr - break - - class AliasedRow(object): - def __init__(self, row): - self.row = row - def __contains__(self, key): - if key in map: - return map[key] in self.row - else: - return key in self.row - def has_key(self, key): - return key in self - def __getitem__(self, key): - if key in map: - key = map[key] - return self.row[key] - def keys(self): - return map.keys() - AliasedRow.map = map - return AliasedRow + def __getitem__(self, key): + return self.row[self.map[key]] + + def keys(self): + return self.row.keys() + +def row_adapter(from_, equivalent_columns=None): + """create a row adapter against a selectable.""" + + if equivalent_columns is None: + equivalent_columns = {} + + def locate_col(col): + c = from_.corresponding_column(col) + if c: + return c + elif col in equivalent_columns: + for c2 in equivalent_columns[col]: + corr = from_.corresponding_column(c2) + if corr: + return corr + return col + + map = util.PopulateDict(locate_col) + + def adapt(row): + return AliasedRow(row, map) + return adapt class ColumnsInClause(visitors.ClauseVisitor): """Given a selectable, visit clauses and determine if any columns @@ -189,7 +194,7 @@ class ClauseAdapter(visitors.ClauseVisitor): if not clone: raise exceptions.ArgumentError("ClauseAdapter 'clone' argument must be True") return visitors.ClauseVisitor.traverse(self, obj, clone=True) - + def copy_and_chain(self, adapter): """create a copy of this adapter and chain to the given adapter. diff --git a/lib/sqlalchemy/sql/visitors.py b/lib/sqlalchemy/sql/visitors.py index 09d5a0982..7eccc9b89 100644 --- a/lib/sqlalchemy/sql/visitors.py +++ b/lib/sqlalchemy/sql/visitors.py @@ -37,17 +37,17 @@ class ClauseVisitor(object): traverse_chained = traverse_single def iterate(self, obj): - """traverse the given expression structure, and return an iterator of all elements.""" + """traverse the given expression structure, returning an iterator of all elements.""" stack = [obj] - traversal = [] - while len(stack) > 0: + traversal = util.deque() + while stack: t = stack.pop() - yield t - traversal.insert(0, t) + traversal.appendleft(t) for c in t.get_children(**self.__traverse_options__): stack.append(c) - + return iter(traversal) + def traverse(self, obj, clone=False): """traverse and visit the given expression structure. @@ -119,32 +119,19 @@ class ClauseVisitor(object): def clone(element): return self._clone_element(element, stop_on, cloned) elem._copy_internals(clone=clone) - - for v in self._iterate_visitors: - meth = getattr(v, "visit_%s" % elem.__visit_name__, None) - if meth: - meth(elem) + + self.traverse_single(elem) for e in elem.get_children(**self.__traverse_options__): if e not in stop_on: self._cloned_traversal_impl(e, stop_on, cloned) return elem - + def _non_cloned_traversal(self, obj): """a non-recursive, non-cloning traversal.""" - - stack = [obj] - traversal = [] - while len(stack) > 0: - t = stack.pop() - traversal.insert(0, t) - for c in t.get_children(**self.__traverse_options__): - stack.append(c) - for target in traversal: - for v in self._iterate_visitors: - meth = getattr(v, "visit_%s" % target.__visit_name__, None) - if meth: - meth(target) + + for target in self.iterate(obj): + self.traverse_single(target) return obj def _iterate_visitors(self): |