From afcab5edf6a3a6e9e83d1940d0be079e92c53e79 Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Sun, 17 Jan 2021 13:35:02 -0500 Subject: Implement support for functions as FROM with columns clause support Implemented support for "table valued functions" along with additional syntaxes supported by PostgreSQL, one of the most commonly requested features. Table valued functions are SQL functions that return lists of values or rows, and are prevalent in PostgreSQL in the area of JSON functions, where the "table value" is commonly referred towards as the "record" datatype. Table valued functions are also supported by Oracle and SQL Server. Moved from I5b093b72533ef695293e737eb75850b9713e5e03 due to accidental push Fixes: #3566 Change-Id: Iea36d04c80a5ed3509dcdd9ebf0701687143fef5 --- lib/sqlalchemy/sql/elements.py | 175 +++++++++++++++++++++++++++++------------ 1 file changed, 123 insertions(+), 52 deletions(-) (limited to 'lib/sqlalchemy/sql/elements.py') diff --git a/lib/sqlalchemy/sql/elements.py b/lib/sqlalchemy/sql/elements.py index a9f21cd5f..1bdef1932 100644 --- a/lib/sqlalchemy/sql/elements.py +++ b/lib/sqlalchemy/sql/elements.py @@ -3856,6 +3856,8 @@ class Over(ColumnElement): .. seealso:: + :ref:`tutorial_window_functions` - in the :ref:`unified_tutorial` + :data:`.expression.func` :func:`_expression.within_group` @@ -4007,6 +4009,9 @@ class WithinGroup(ColumnElement): .. seealso:: + :ref:`tutorial_functions_within_group` - in the + :ref:`unified_tutorial` + :data:`.expression.func` :func:`_expression.over` @@ -4104,8 +4109,10 @@ class FunctionFilter(ColumnElement): .. seealso:: - :meth:`.FunctionElement.filter` + :ref:`tutorial_functions_within_group` - in the + :ref:`unified_tutorial` + :meth:`.FunctionElement.filter` """ self.func = func @@ -4317,11 +4324,82 @@ class Label(roles.LabeledColumnExprRole, ColumnElement): return self.key, e +class NamedColumn(ColumnElement): + is_literal = False + table = None + + def _compare_name_for_result(self, other): + return (hasattr(other, "name") and self.name == other.name) or ( + hasattr(other, "_label") and self._label == other._label + ) + + @util.memoized_property + def description(self): + if util.py3k: + return self.name + else: + return self.name.encode("ascii", "backslashreplace") + + @HasMemoized.memoized_attribute + def _key_label(self): + if self.key != self.name: + return self._gen_label(self.key) + else: + return self._label + + @HasMemoized.memoized_attribute + def _label(self): + return self._gen_label(self.name) + + @HasMemoized.memoized_attribute + def _render_label_in_columns_clause(self): + return True + + def _gen_label(self, name, dedupe_on_key=True): + return name + + def _bind_param(self, operator, obj, type_=None, expanding=False): + return BindParameter( + self.key, + obj, + _compared_to_operator=operator, + _compared_to_type=self.type, + type_=type_, + unique=True, + expanding=expanding, + ) + + def _make_proxy( + self, + selectable, + name=None, + name_is_truncatable=False, + disallow_is_literal=False, + **kw + ): + c = ColumnClause( + coercions.expect(roles.TruncatedLabelRole, name or self.name) + if name_is_truncatable + else (name or self.name), + type_=self.type, + _selectable=selectable, + is_literal=False, + ) + c._propagate_attrs = selectable._propagate_attrs + if name is None: + c.key = self.key + c._proxies = [self] + if selectable._is_clone_of is not None: + c._is_clone_of = selectable._is_clone_of.columns.get(c.key) + return c.key, c + + class ColumnClause( roles.DDLReferredColumnRole, roles.LabeledColumnExprRole, + roles.StrAsPlainColumnRole, Immutable, - ColumnElement, + NamedColumn, ): """Represents a column expression from any textual string. @@ -4360,6 +4438,9 @@ class ColumnClause( """ + table = None + is_literal = False + __visit_name__ = "column" _traverse_internals = [ @@ -4470,27 +4551,6 @@ class ColumnClause( self.type = type_api.to_instance(type_) self.is_literal = is_literal - def _compare_name_for_result(self, other): - if ( - self.is_literal - or self.table is None - or self.table._is_textual - or not hasattr(other, "proxy_set") - or ( - isinstance(other, ColumnClause) - and ( - other.is_literal - or other.table is None - or other.table._is_textual - ) - ) - ): - return (hasattr(other, "name") and self.name == other.name) or ( - hasattr(other, "_label") and self._label == other._label - ) - else: - return other.proxy_set.intersection(self.proxy_set) - def get_children(self, column_tables=False, **kw): # override base get_children() to not return the Table # or selectable that is parent to this column. Traversals @@ -4505,24 +4565,6 @@ class ColumnClause( else: return [] - @util.memoized_property - def description(self): - if util.py3k: - return self.name - else: - return self.name.encode("ascii", "backslashreplace") - - @HasMemoized.memoized_attribute - def _key_label(self): - if self.key != self.name: - return self._gen_label(self.key) - else: - return self._label - - @HasMemoized.memoized_attribute - def _label(self): - return self._gen_label(self.name) - @HasMemoized.memoized_attribute def _render_label_in_columns_clause(self): return self.table is not None @@ -4531,6 +4573,27 @@ class ColumnClause( def _ddl_label(self): return self._gen_label(self.name, dedupe_on_key=False) + def _compare_name_for_result(self, other): + if ( + self.is_literal + or self.table is None + or self.table._is_textual + or not hasattr(other, "proxy_set") + or ( + isinstance(other, ColumnClause) + and ( + other.is_literal + or other.table is None + or other.table._is_textual + ) + ) + ): + return (hasattr(other, "name") and self.name == other.name) or ( + hasattr(other, "_label") and self._label == other._label + ) + else: + return other.proxy_set.intersection(self.proxy_set) + def _gen_label(self, name, dedupe_on_key=True): t = self.table if self.is_literal: @@ -4575,17 +4638,6 @@ class ColumnClause( else: return name - def _bind_param(self, operator, obj, type_=None, expanding=False): - return BindParameter( - self.key, - obj, - _compared_to_operator=operator, - _compared_to_type=self.type, - type_=type_, - unique=True, - expanding=expanding, - ) - def _make_proxy( self, selectable, @@ -4627,6 +4679,25 @@ class ColumnClause( return c.key, c +class TableValuedColumn(NamedColumn): + __visit_name__ = "table_valued_column" + + _traverse_internals = [ + ("name", InternalTraversal.dp_anon_name), + ("type", InternalTraversal.dp_type), + ("scalar_alias", InternalTraversal.dp_clauseelement), + ] + + def __init__(self, scalar_alias, type_): + self.scalar_alias = scalar_alias + self.key = self.name = scalar_alias.name + self.type = type_ + + @property + def _from_objects(self): + return [self.scalar_alias] + + class CollationClause(ColumnElement): __visit_name__ = "collation" -- cgit v1.2.1