diff options
Diffstat (limited to 'lib/sqlalchemy/sql')
| -rw-r--r-- | lib/sqlalchemy/sql/compiler.py | 4 | ||||
| -rw-r--r-- | lib/sqlalchemy/sql/expression.py | 64 |
2 files changed, 46 insertions, 22 deletions
diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py index 8f2e3372a..666a38d39 100644 --- a/lib/sqlalchemy/sql/compiler.py +++ b/lib/sqlalchemy/sql/compiler.py @@ -464,7 +464,7 @@ class DefaultCompiler(engine.Compiled): not isinstance(column.table, sql.Select): return column.label(column.name) elif not isinstance(column, (sql._UnaryExpression, sql._TextClause)) and (not hasattr(column, 'name') or isinstance(column, sql._Function)): - return column.label(None) + return column.anon_label else: return column @@ -728,7 +728,7 @@ class DefaultCompiler(engine.Compiled): return "RELEASE SAVEPOINT %s" % self.preparer.format_savepoint(savepoint_stmt) def __str__(self): - return self.string + return self.string or '' class DDLBase(engine.SchemaIterator): def find_alterables(self, tables): diff --git a/lib/sqlalchemy/sql/expression.py b/lib/sqlalchemy/sql/expression.py index 3ebc4960f..c60341802 100644 --- a/lib/sqlalchemy/sql/expression.py +++ b/lib/sqlalchemy/sql/expression.py @@ -1402,17 +1402,37 @@ class ColumnElement(ClauseElement, _CompareMixin): ``ColumnElement`` as it appears in the select list of a descending selectable. - The default implementation returns a ``_ColumnClause`` if a - name is given, else just returns self. """ if name is not None: - co = _ColumnClause(name, selectable) + co = _ColumnClause(name, selectable, type_=getattr(self, 'type', None)) co.proxies = [self] selectable.columns[name]= co return co else: - return self + name = str(self) + co = _ColumnClause(self.anon_label.name, 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 = self.label(None) + return self.__anon_label + anon_label = property(anon_label) class ColumnCollection(util.OrderedProperties): """An ordered dictionary that stores a list of ColumnElement @@ -2026,15 +2046,6 @@ class _Cast(ColumnElement): def _get_from_objects(self, **modifiers): return self.clause._get_from_objects(**modifiers) - def _make_proxy(self, selectable, name=None): - if name is not None: - co = _ColumnClause(name, selectable, type_=self.type) - co.proxies = [self] - selectable.columns[name]= co - return co - else: - return self - class _UnaryExpression(ColumnElement): def __init__(self, element, operator=None, modifier=None, type_=None, negate=None): @@ -2864,8 +2875,16 @@ class CompoundSelect(_SelectBaseMixin, FromClause): 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 @@ -2892,17 +2911,22 @@ class CompoundSelect(_SelectBaseMixin, FromClause): yield c def _proxy_column(self, column): - existing = self._col_map.get(column.name, None) - if existing is not None: - existing.proxies.append(column) - return existing - else: + selectable = column.table + col_ordering = self._col_map.get(selectable, None) + if col_ordering is None: + self._col_map[selectable] = col_ordering = [] + + if selectable is self.selects[0]: if self.use_labels: col = column._make_proxy(self, name=column._label) else: col = column._make_proxy(self) - self._col_map[col.name] = col - return col + col_ordering.append(col) + else: + col_ordering.append(column) + existing = self._col_map[self.selects[0]][len(col_ordering) - 1] + existing.proxies.append(column) + return existing def _copy_internals(self, clone=_clone): self._clone_from_clause() |