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/dialects/oracle/base.py | 13 + lib/sqlalchemy/dialects/postgresql/array.py | 2 + lib/sqlalchemy/dialects/postgresql/base.py | 188 ++++++++++++-- lib/sqlalchemy/sql/base.py | 10 +- lib/sqlalchemy/sql/coercions.py | 21 ++ lib/sqlalchemy/sql/compiler.py | 64 ++++- lib/sqlalchemy/sql/elements.py | 175 +++++++++---- lib/sqlalchemy/sql/expression.py | 2 + lib/sqlalchemy/sql/functions.py | 382 +++++++++++++++++++++++++--- lib/sqlalchemy/sql/roles.py | 4 + lib/sqlalchemy/sql/selectable.py | 178 ++++++++++++- lib/sqlalchemy/sql/sqltypes.py | 64 +++-- lib/sqlalchemy/sql/traversals.py | 5 +- lib/sqlalchemy/sql/type_api.py | 2 + lib/sqlalchemy/sql/visitors.py | 6 +- lib/sqlalchemy/testing/requirements.py | 12 + lib/sqlalchemy/testing/suite/test_select.py | 17 ++ 17 files changed, 992 insertions(+), 153 deletions(-) (limited to 'lib/sqlalchemy') diff --git a/lib/sqlalchemy/dialects/oracle/base.py b/lib/sqlalchemy/dialects/oracle/base.py index 6c381a2ec..9344abeee 100644 --- a/lib/sqlalchemy/dialects/oracle/base.py +++ b/lib/sqlalchemy/dialects/oracle/base.py @@ -924,6 +924,19 @@ class OracleCompiler(compiler.SQLCompiler): else: return "" + def visit_function(self, func, **kw): + text = super(OracleCompiler, self).visit_function(func, **kw) + if kw.get("asfrom", False): + text = "TABLE (%s)" % func + return text + + def visit_table_valued_column(self, element, **kw): + text = super(OracleCompiler, self).visit_table_valued_column( + element, **kw + ) + text = "COLUMN_VALUE " + text + return text + def default_from(self): """Called when a ``SELECT`` statement has no froms, and no ``FROM`` clause is to be appended. diff --git a/lib/sqlalchemy/dialects/postgresql/array.py b/lib/sqlalchemy/dialects/postgresql/array.py index ad71db89e..91bb89ea9 100644 --- a/lib/sqlalchemy/dialects/postgresql/array.py +++ b/lib/sqlalchemy/dialects/postgresql/array.py @@ -96,6 +96,8 @@ class array(expression.ClauseList, expression.ColumnElement): __visit_name__ = "array" + stringify_dialect = "postgresql" + def __init__(self, clauses, **kw): clauses = [ coercions.expect(roles.ExpressionElementRole, c) for c in clauses diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py index 08d7cd9e5..f067e6537 100644 --- a/lib/sqlalchemy/dialects/postgresql/base.py +++ b/lib/sqlalchemy/dialects/postgresql/base.py @@ -1038,26 +1038,157 @@ dialect in conjunction with the :class:`_schema.Table` construct: `PostgreSQL CREATE TABLE options `_ -Table values, Row and Tuple objects ------------------------------------ +.. _postgresql_table_valued_overview: -Row Types -^^^^^^^^^ +Table values, Table and Column valued functions, Row and Tuple objects +----------------------------------------------------------------------- + +PostgreSQL makes great use of modern SQL forms such as table-valued functions, +tables and rows as values. These constructs are commonly used as part +of PostgreSQL's support for complex datatypes such as JSON, ARRAY, and other +datatypes. SQLAlchemy's SQL expression language has native support for +most table-valued and row-valued forms. + +.. _postgresql_table_valued: + +Table-Valued Functions +^^^^^^^^^^^^^^^^^^^^^^^ + +Many PostgreSQL built-in functions are intended to be used in the FROM clause +of a SELECT statement, and are capable of returning table rows or sets of table +rows. A large portion of PostgreSQL's JSON functions for example such as +``json_array_elements()``, ``json_object_keys()``, ``json_each_text()``, +``json_each()``, ``json_to_record()``, ``json_populate_recordset()`` use such +forms. These classes of SQL function calling forms in SQLAlchemy are available +using the :meth:`_functions.FunctionElement.table_valued` method in conjunction +with :class:`_function.Function` objects generated from the :data:`_sql.func` +namespace. -Built-in support for rendering a ``ROW`` is not available yet, however the -:func:`_expression.tuple_` may be used in its place. Another alternative is -to use the :attr:`_sa.func` generator with ``func.ROW`` :: +Examples from PostgreSQL's reference documentation follow below: - table.select().where( - tuple_(table.c.id, table.c.fk) > (1,2) - ).where(func.ROW(table.c.id, table.c.fk) < func.ROW(3, 7)) +* ``json_each()``:: -Will generate the row-wise comparison:: + >>> from sqlalchemy import select, func + >>> stmt = select(func.json_each('{"a":"foo", "b":"bar"}').table_valued("key", "value")) + >>> print(stmt) + SELECT anon_1.key, anon_1.value + FROM json_each(:json_each_1) AS anon_1 - SELECT * - FROM table - WHERE (id, fk) > (1, 2) - AND ROW(id, fk) < ROW(3, 7) +* ``json_populate_record()``:: + + >>> from sqlalchemy import select, func, literal_column + >>> stmt = select( + ... func.json_populate_record( + ... literal_column("null::myrowtype"), + ... '{"a":1,"b":2}' + ... ).table_valued("a", "b", name="x") + ... ) + >>> print(stmt) + SELECT x.a, x.b + FROM json_populate_record(null::myrowtype, :json_populate_record_1) AS x + +* ``json_to_record()`` - this form uses a PostgreSQL specific form of derived + columns in the alias, where we may make use of :func:`_sql.column` elements with + types to produce them. The :meth:`_functions.FunctionElement.table_valued` + method produces a :class:`_sql.TableValuedAlias` construct, and the method + :meth:`_sql.TableValuedAlias.render_derived` method sets up the derived + columns specification:: + + >>> from sqlalchemy import select, func, column, Integer, Text + >>> stmt = select( + ... func.json_to_record('{"a":1,"b":[1,2,3],"c":"bar"}').table_valued( + ... column("a", Integer), column("b", Text), column("d", Text), + ... ).render_derived(name="x", with_types=True) + ... ) + >>> print(stmt) + SELECT x.a, x.b, x.d + FROM json_to_record(:json_to_record_1) AS x(a INTEGER, b TEXT, d TEXT) + +* ``WITH ORDINALITY`` - part of the SQL standard, ``WITH ORDINALITY`` adds an + ordinal counter to the output of a function and is accepted by a limited set + of PostgreSQL functions including ``unnest()`` and ``generate_series()``. The + :meth:`_functions.FunctionElement.table_valued` method accepts a keyword + parameter ``with_ordinality`` for this purpose, which accepts the string name + that will be applied to the "ordinality" column:: + + >>> from sqlalchemy import select, func + >>> stmt = select( + ... func.generate_series(4, 1, -1).table_valued("value", with_ordinality="ordinality") + ... ) + >>> print(stmt) + SELECT anon_1.value, anon_1.ordinality + FROM generate_series(:generate_series_1, :generate_series_2, :generate_series_3) WITH ORDINALITY AS anon_1 + +.. versionadded:: 1.4.0b2 + +.. seealso:: + + :ref:`tutorial_functions_table_valued` - in the :ref:`unified_tutorial` + +.. _postgresql_column_valued: + +Column Valued Functions +^^^^^^^^^^^^^^^^^^^^^^^ + +Similar to the table valued function, a column valued function is present +in the FROM clause, but delivers itself to the columns clause as a single +scalar value. PostgreSQL functions such as ``json_array_elements()``, +``unnest()`` and ``generate_series()`` may use this form. Column valued functions are available using the +:meth:`_functions.FunctionElement.column_valued` method of :class:`_functions.FunctionElement`: + +* ``json_array_elements()``:: + + >>> from sqlalchemy import select, func + >>> stmt = select(func.json_array_elements('["one", "two"]').column_valued("x")) + >>> print(stmt) + SELECT x + FROM json_array_elements(:json_array_elements_1) AS x + +* ``unnest()`` - in order to generate a PostgreSQL ARRAY literal, the + :func:`_postgresql.array` construct may be used:: + + + >>> from sqlalchemy.dialects.postgresql import array + >>> from sqlalchemy import select, func + >>> stmt = select(func.unnest(array([1, 2])).column_valued()) + >>> print(stmt) + SELECT anon_1 + FROM unnest(ARRAY[%(param_1)s, %(param_2)s]) AS anon_1 + + The function can of course be used against an existing table-bound column + that's of type :class:`_types.ARRAY`:: + + >>> from sqlalchemy import table, column, ARRAY, Integer + >>> from sqlalchemy import select, func + >>> t = table("t", column('value', ARRAY(Integer))) + >>> stmt = select(func.unnest(t.c.value).column_valued("unnested_value")) + >>> print(stmt) + SELECT unnested_value + FROM unnest(t.value) AS unnested_value + +.. seealso:: + + :ref:`tutorial_functions_column_valued` - in the :ref:`unified_tutorial` + + +Row Types +^^^^^^^^^ + +Built-in support for rendering a ``ROW`` may be approximated using +``func.ROW`` with the :attr:`_sa.func` namespace, or by using the +:func:`_sql.tuple_` construct:: + + >>> from sqlalchemy import table, column, func, tuple_ + >>> t = table("t", column("id"), column("fk")) + >>> stmt = t.select().where( + ... tuple_(t.c.id, t.c.fk) > (1,2) + ... ).where( + ... func.ROW(t.c.id, t.c.fk) < func.ROW(3, 7) + ... ) + >>> print(stmt) + SELECT t.id, t.fk + FROM t + WHERE (t.id, t.fk) > (:param_1, :param_2) AND ROW(t.id, t.fk) < ROW(:ROW_1, :ROW_2) .. seealso:: @@ -1067,20 +1198,27 @@ Will generate the row-wise comparison:: `PostgreSQL Row Constructor Comparison `_ -Table Types -^^^^^^^^^^^ +Table Types passed to Functions +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ -PostgreSQL also supports passing a table as an argument to a function. This -is not available yet in sqlalchemy, however the -:func:`_expression.literal_column` function with the name of the table may be -used in its place:: +PostgreSQL supports passing a table as an argument to a function, which it +refers towards as a "record" type. SQLAlchemy :class:`_sql.FromClause` objects +such as :class:`_schema.Table` support this special form using the +:meth:`_sql.FromClause.table_valued` method, which is comparable to the +:meth:`_functions.FunctionElement.table_valued` method except that the collection +of columns is already established by that of the :class:`_sql.FromClause` +itself:: - select('*').select_from(func.my_function(literal_column('my_table'))) -Will generate the SQL:: + >>> from sqlalchemy import table, column, func, select + >>> a = table( "a", column("id"), column("x"), column("y")) + >>> stmt = select(func.row_to_json(a.table_valued())) + >>> print(stmt) + SELECT row_to_json(a) AS row_to_json_1 + FROM a + +.. versionadded:: 1.4.0b2 - SELECT * - FROM my_function(my_table) ARRAY Types ----------- diff --git a/lib/sqlalchemy/sql/base.py b/lib/sqlalchemy/sql/base.py index fe9455fb9..c76c9ae14 100644 --- a/lib/sqlalchemy/sql/base.py +++ b/lib/sqlalchemy/sql/base.py @@ -935,13 +935,11 @@ class Executable(roles.CoerceTextStatementRole, Generative): @util.deprecated_20( ":meth:`.Executable.scalar`", - alternative="All statement execution in SQLAlchemy 2.0 is performed " - "by the :meth:`_engine.Connection.execute` method of " + alternative="Scalar execution in SQLAlchemy 2.0 is performed " + "by the :meth:`_engine.Connection.scalar` method of " ":class:`_engine.Connection`, " - "or in the ORM by the :meth:`.Session.execute` method of " - ":class:`.Session`; the :meth:`_future.Result.scalar` " - "method can then be " - "used to return a scalar result.", + "or in the ORM by the :meth:`.Session.scalar` method of " + ":class:`.Session`.", ) def scalar(self, *multiparams, **params): """Compile and execute this :class:`.Executable`, returning the diff --git a/lib/sqlalchemy/sql/coercions.py b/lib/sqlalchemy/sql/coercions.py index 3b972be41..d4b208c56 100644 --- a/lib/sqlalchemy/sql/coercions.py +++ b/lib/sqlalchemy/sql/coercions.py @@ -437,6 +437,20 @@ class ExpressionElementImpl(_ColumnCoercions, RoleImpl): except exc.ArgumentError as err: self._raise_for_expected(element, err=err) + def _raise_for_expected(self, element, argname=None, resolved=None, **kw): + if isinstance(element, roles.AnonymizedFromClauseRole): + advice = ( + "To create a " + "column expression from a FROM clause row " + "as a whole, use the .table_valued() method." + ) + else: + advice = None + + return super(ExpressionElementImpl, self)._raise_for_expected( + element, argname=argname, resolved=resolved, advice=advice, **kw + ) + class BinaryElementImpl(ExpressionElementImpl, RoleImpl): @@ -603,6 +617,13 @@ class ColumnArgumentOrKeyImpl(_ReturnsStringKey, RoleImpl): __slots__ = () +class StrAsPlainColumnImpl(_CoerceLiterals, RoleImpl): + __slots__ = () + + def _text_coercion(self, element, argname=None): + return elements.ColumnClause(element) + + class ByOfImpl(_CoerceLiterals, _ColumnCoercions, RoleImpl, roles.ByOfRole): __slots__ = () diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py index 3925b251d..696b38e64 100644 --- a/lib/sqlalchemy/sql/compiler.py +++ b/lib/sqlalchemy/sql/compiler.py @@ -494,6 +494,12 @@ class Compiled(object): else: raise exc.ObjectNotExecutableError(self.statement) + def visit_unsupported_compilation(self, element, err): + util.raise_( + exc.UnsupportedCompilationError(self, type(element)), + replace_context=err, + ) + @property def sql_compiler(self): """Return a Compiled that is capable of processing SQL expressions. @@ -1718,13 +1724,18 @@ class SQLCompiler(Compiled): extract.expr._compiler_dispatch(self, **kwargs), ) + def visit_scalar_function_column(self, element, **kw): + compiled_fn = self.visit_function(element.fn, **kw) + compiled_col = self.visit_column(element, **kw) + return "(%s).%s" % (compiled_fn, compiled_col) + def visit_function(self, func, add_to_result_map=None, **kwargs): if add_to_result_map is not None: add_to_result_map(func.name, func.name, (), func.type) disp = getattr(self, "visit_%s_func" % func.name.lower(), None) if disp: - return disp(func, **kwargs) + text = disp(func, **kwargs) else: name = FUNCTIONS.get(func.__class__, None) if name: @@ -1739,7 +1750,7 @@ class SQLCompiler(Compiled): else name ) name = name + "%(expr)s" - return ".".join( + text = ".".join( [ ( self.preparer.quote(tok) @@ -1752,6 +1763,10 @@ class SQLCompiler(Compiled): + [name] ) % {"expr": self.function_argspec(func, **kwargs)} + if func._with_ordinality: + text += " WITH ORDINALITY" + return text + def visit_next_value_func(self, next_value, **kw): return self.visit_sequence(next_value.sequence) @@ -2533,6 +2548,15 @@ class SQLCompiler(Compiled): else: return self.preparer.format_alias(cte, cte_name) + def visit_table_valued_alias(self, element, **kw): + if element._is_lateral: + return self.visit_lateral(element, **kw) + else: + return self.visit_alias(element, **kw) + + def visit_table_valued_column(self, element, **kw): + return self.visit_column(element, **kw) + def visit_alias( self, alias, @@ -2584,6 +2608,24 @@ class SQLCompiler(Compiled): ret = inner + self.get_render_as_alias_suffix( self.preparer.format_alias(alias, alias_name) ) + + if alias._supports_derived_columns and alias._render_derived: + ret += "(%s)" % ( + ", ".join( + "%s%s" + % ( + col.name, + " %s" + % self.dialect.type_compiler.process( + col.type, **kwargs + ) + if alias._render_derived_w_types + else "", + ) + for col in alias.c + ) + ) + if fromhints and alias in fromhints: ret = self.format_from_hint_text( ret, alias, fromhints[alias], iscrud @@ -2600,9 +2642,9 @@ class SQLCompiler(Compiled): kw["subquery"] = True return self.visit_alias(subquery, **kw) - def visit_lateral(self, lateral, **kw): + def visit_lateral(self, lateral_, **kw): kw["lateral"] = True - return "LATERAL %s" % self.visit_alias(lateral, **kw) + return "LATERAL %s" % self.visit_alias(lateral_, **kw) def visit_tablesample(self, tablesample, asfrom=False, **kw): text = "%s TABLESAMPLE %s" % ( @@ -3737,6 +3779,20 @@ class StrSQLCompiler(SQLCompiler): def _fallback_column_name(self, column): return "" + @util.preload_module("sqlalchemy.engine.url") + def visit_unsupported_compilation(self, element, err, **kw): + if element.stringify_dialect != "default": + url = util.preloaded.engine_url + dialect = url.URL.create(element.stringify_dialect).get_dialect()() + + compiler = dialect.statement_compiler(dialect, None) + if not isinstance(compiler, StrSQLCompiler): + return compiler.process(element) + + return super(StrSQLCompiler, self).visit_unsupported_compilation( + element, err + ) + def visit_getitem_binary(self, binary, operator, **kw): return "%s[%s]" % ( self.process(binary.left, **kw), 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" diff --git a/lib/sqlalchemy/sql/expression.py b/lib/sqlalchemy/sql/expression.py index 3eb1443a3..46f13fedd 100644 --- a/lib/sqlalchemy/sql/expression.py +++ b/lib/sqlalchemy/sql/expression.py @@ -34,6 +34,7 @@ __all__ = [ "Select", "Selectable", "TableClause", + "TableValuedAlias", "Update", "Values", "alias", @@ -172,6 +173,7 @@ from .selectable import Subquery # noqa from .selectable import subquery # noqa from .selectable import TableClause # noqa from .selectable import TableSample # noqa +from .selectable import TableValuedAlias # noqa from .selectable import TextAsFrom # noqa from .selectable import TextualSelect # noqa from .selectable import Values # noqa diff --git a/lib/sqlalchemy/sql/functions.py b/lib/sqlalchemy/sql/functions.py index a9ea98d04..78f7ead2e 100644 --- a/lib/sqlalchemy/sql/functions.py +++ b/lib/sqlalchemy/sql/functions.py @@ -17,6 +17,7 @@ from . import sqltypes from . import util as sqlutil from .base import ColumnCollection from .base import Executable +from .base import Generative from .base import HasMemoized from .elements import _type_from_args from .elements import BinaryExpression @@ -28,11 +29,12 @@ from .elements import Extract from .elements import FunctionFilter from .elements import Grouping from .elements import literal_column +from .elements import NamedColumn from .elements import Over from .elements import WithinGroup -from .selectable import Alias from .selectable import FromClause from .selectable import Select +from .selectable import TableValuedAlias from .visitors import InternalTraversal from .visitors import TraversibleType from .. import util @@ -63,7 +65,7 @@ def register_function(identifier, fn, package="_default"): reg[identifier] = fn -class FunctionElement(Executable, ColumnElement, FromClause): +class FunctionElement(Executable, ColumnElement, FromClause, Generative): """Base for SQL function-oriented constructs. .. seealso:: @@ -80,11 +82,17 @@ class FunctionElement(Executable, ColumnElement, FromClause): """ - _traverse_internals = [("clause_expr", InternalTraversal.dp_clauseelement)] + _traverse_internals = [ + ("clause_expr", InternalTraversal.dp_clauseelement), + ("_with_ordinality", InternalTraversal.dp_boolean), + ("_table_value_type", InternalTraversal.dp_has_cache_key), + ] packagenames = () _has_args = False + _with_ordinality = False + _table_value_type = None def __init__(self, *clauses, **kwargs): r"""Construct a :class:`.FunctionElement`. @@ -123,27 +131,169 @@ class FunctionElement(Executable, ColumnElement, FromClause): self, multiparams, params, execution_options ) + def scalar_table_valued(self, name, type_=None): + """Return a column expression that's against this + :class:`_functions.FunctionElement` as a scalar + table-valued expression. + + The returned expression is similar to that returned by a single column + accessed off of a :meth:`_functions.FunctionElement.table_valued` + construct, except no FROM clause is generated; the function is rendered + in the similar way as a scalar subquery. + + E.g.:: + + >>> from sqlalchemy import func, select + >>> fn = func.jsonb_each("{'k', 'v'}").scalar_table_valued("key") + >>> print(select(fn)) + SELECT (jsonb_each(:jsonb_each_1)).key + + .. versionadded:: 1.4.0b2 + + .. seealso:: + + :meth:`_functions.FunctionElement.table_valued` + + :meth:`_functions.FunctionElement.alias` + + :meth:`_functions.FunctionElement.column_valued` + + """ # noqa E501 + + return ScalarFunctionColumn(self, name, type_) + + def table_valued(self, *expr, **kw): + """Return a :class:`_sql.TableValuedAlias` representation of this + :class:`_functions.FunctionElement` with table-valued expressions added. + + e.g.:: + + >>> fn = ( + ... func.generate_series(1, 5). + ... table_valued("value", "start", "stop", "step") + ... ) + + >>> print(select(fn)) + SELECT anon_1.value, anon_1.start, anon_1.stop, anon_1.step + FROM generate_series(:generate_series_1, :generate_series_2) AS anon_1 + + >>> print(select(fn.c.value, fn.c.stop).where(fn.c.value > 2)) + SELECT anon_1.value, anon_1.stop + FROM generate_series(:generate_series_1, :generate_series_2) AS anon_1 + WHERE anon_1.value > :value_1 + + A WITH ORDINALITY expression may be generated by passing the keyword + argument "with_ordinality":: + + >>> fn = func.generate_series(4, 1, -1).table_valued("gen", with_ordinality="ordinality") + >>> print(select(fn)) + SELECT anon_1.gen, anon_1.ordinality + FROM generate_series(:generate_series_1, :generate_series_2, :generate_series_3) WITH ORDINALITY AS anon_1 + + :param \*expr: A series of string column names that will be added to the + ``.c`` collection of the resulting :class:`_sql.TableValuedAlias` + construct as columns. :func:`_sql.column` objects with or without + datatypes may also be used. + + :param name: optional name to assign to the alias name that's generated. + If omitted, a unique anonymizing name is used. + + :param with_ordinality: string name that when present results in the + ``WITH ORDINALITY`` clause being added to the alias, and the given + string name will be added as a column to the .c collection + of the resulting :class:`_sql.TableValuedAlias`. + + .. versionadded:: 1.4.0b2 + + .. seealso:: + + :ref:`tutorial_functions_table_valued` - in the :ref:`unified_tutorial` + + :ref:`postgresql_table_valued` - in the :ref:`postgresql_toplevel` documentation + + :meth:`_functions.FunctionElement.scalar_table_valued` - variant of + :meth:`_functions.FunctionElement.table_valued` which delivers the + complete table valued expression as a scalar column expression + + :meth:`_functions.FunctionElement.column_valued` + + :meth:`_sql.TableValuedAlias.render_derived` - renders the alias + using a derived column clause, e.g. ``AS name(col1, col2, ...)`` + + """ # noqa 501 + + new_func = self._generate() + + with_ordinality = kw.pop("with_ordinality", None) + name = kw.pop("name", None) + + if with_ordinality: + expr += (with_ordinality,) + new_func._with_ordinality = True + + new_func.type = new_func._table_value_type = sqltypes.TableValueType( + *expr + ) + + return new_func.alias(name=name) + + def column_valued(self, name=None): + """Return this :class:`_functions.FunctionElement` as a column expression that + selects from itself as a FROM clause. + + E.g.:: + + >>> from sqlalchemy import select, func + >>> gs = func.generate_series(1, 5, -1).column_valued() + >>> print(select(gs)) + SELECT anon_1 + FROM generate_series(:generate_series_1, :generate_series_2, :generate_series_3) AS anon_1 + + This is shorthand for:: + + gs = func.generate_series(1, 5, -1).alias().column + + + .. seealso:: + + :ref:`tutorial_functions_column_valued` - in the :ref:`unified_tutorial` + + :ref:`postgresql_column_valued` - in the :ref:`postgresql_toplevel` documentation + + :meth:`_functions.FunctionElement.table_valued` + + """ # noqa 501 + + return self.alias(name=name).column + @property def columns(self): r"""The set of columns exported by this :class:`.FunctionElement`. - Function objects currently have no result column names built in; - this method returns a single-element column collection with - an anonymously named column. + This is a placeholder collection that allows the function to be + placed in the FROM clause of a statement:: - An interim approach to providing named columns for a function - as a FROM clause is to build a :func:`_expression.select` with the - desired columns:: + >>> from sqlalchemy import column, select, func + >>> stmt = select(column('x'), column('y')).select_from(func.myfunction()) + >>> print(stmt) + SELECT x, y FROM myfunction() - from sqlalchemy.sql import column + The above form is a legacy feature that is now superseded by the + fully capable :meth:`_functions.FunctionElement.table_valued` + method; see that method for details. - stmt = select(column('x'), column('y')).\ - select_from(func.myfunction()) + .. seealso:: + :meth:`_functions.FunctionElement.table_valued` - generates table-valued + SQL function expressions. - """ - col = self.label(None) - return ColumnCollection(columns=[(col.key, col)]) + """ # noqa E501 + if self.type._is_table_value: + cols = self.type._elements + else: + cols = [self.label(None)] + + return ColumnCollection(columns=[(col.key, col) for col in cols]) @HasMemoized.memoized_attribute def clauses(self): @@ -170,6 +320,12 @@ class FunctionElement(Executable, ColumnElement, FromClause): See :func:`_expression.over` for a full description. + .. seealso:: + + :func:`_expression.over` + + :ref:`tutorial_window_functions` - in the :ref:`unified_tutorial` + """ return Over( self, @@ -191,6 +347,12 @@ class FunctionElement(Executable, ColumnElement, FromClause): .. versionadded:: 1.1 + .. seealso:: + + :ref:`tutorial_functions_within_group` - + in the :ref:`unified_tutorial` + + """ return WithinGroup(self, *order_by) @@ -213,6 +375,9 @@ class FunctionElement(Executable, ColumnElement, FromClause): .. seealso:: + :ref:`tutorial_functions_within_group` - + in the :ref:`unified_tutorial` + :class:`.FunctionFilter` :func:`.funcfilter` @@ -226,6 +391,9 @@ class FunctionElement(Executable, ColumnElement, FromClause): def as_comparison(self, left_index, right_index): """Interpret this expression as a boolean comparison between two values. + This method is used for an ORM use case described at + :ref:`relationship_custom_operator_sql_function`. + A hypothetical SQL function "is_equal()" which compares to values for equality would be written in the Core expression language as:: @@ -250,9 +418,8 @@ class FunctionElement(Executable, ColumnElement, FromClause): to manipulate the "left" and "right" sides of the ON clause of a JOIN expression. The purpose of this method is to provide a SQL function construct that can also supply this information to the ORM, when used - with the :paramref:`_orm.relationship.primaryjoin` parameter. - The return - value is a containment object called :class:`.FunctionAsBinary`. + with the :paramref:`_orm.relationship.primaryjoin` parameter. The + return value is a containment object called :class:`.FunctionAsBinary`. An ORM example is as follows:: @@ -286,6 +453,11 @@ class FunctionElement(Executable, ColumnElement, FromClause): .. versionadded:: 1.3 + .. seealso:: + + :ref:`relationship_custom_operator_sql_function` - + example use within the ORM + """ return FunctionAsBinary(self, left_index, right_index) @@ -305,37 +477,65 @@ class FunctionElement(Executable, ColumnElement, FromClause): return None - def alias(self, name=None, flat=False): + def alias(self, name=None): r"""Produce a :class:`_expression.Alias` construct against this :class:`.FunctionElement`. + .. tip:: + + The :meth:`_functions.FunctionElement.alias` method is part of the + mechanism by which "table valued" SQL functions are created. + However, most use cases are covered by higher level methods on + :class:`_functions.FunctionElement` including + :meth:`_functions.FunctionElement.table_valued`, and + :meth:`_functions.FunctionElement.column_valued`. + This construct wraps the function in a named alias which is suitable for the FROM clause, in the style accepted for example - by PostgreSQL. + by PostgreSQL. A column expression is also provided using the + special ``.column`` attribute, which may + be used to refer to the output of the function as a scalar value + in the columns or where clause, for a backend such as PostgreSQL. + + For a full table-valued expression, use the + :meth:`_function.FunctionElement.table_valued` method first to + establish named columns. e.g.:: - from sqlalchemy.sql import column + >>> from sqlalchemy import func, select, column + >>> data_view = func.unnest([1, 2, 3]).alias("data_view") + >>> print(select(data_view.column)) + SELECT data_view + FROM unnest(:unnest_1) AS data_view - stmt = select(column('data_view')).\ - select_from(SomeTable).\ - select_from(func.unnest(SomeTable.data).alias('data_view') - ) + The :meth:`_functions.FunctionElement.column_valued` method provides + a shortcut for the above pattern:: - Would produce: + >>> data_view = func.unnest([1, 2, 3]).column_valued("data_view") + >>> print(select(data_view)) + SELECT data_view + FROM unnest(:unnest_1) AS data_view - .. sourcecode:: sql + .. versionadded:: 1.4.0b2 Added the ``.column`` accessor - SELECT data_view - FROM sometable, unnest(sometable.data) AS data_view + .. seealso:: + + :ref:`tutorial_functions_table_valued` - + in the :ref:`unified_tutorial` + + :meth:`_functions.FunctionElement.table_valued` + + :meth:`_functions.FunctionElement.scalar_table_valued` + + :meth:`_functions.FunctionElement.column_valued` - .. versionadded:: 0.9.8 The :meth:`.FunctionElement.alias` method - is now supported. Previously, this method's behavior was - undefined and did not behave consistently across versions. """ - return Alias._construct(self, name) + return TableValuedAlias._construct( + self, name, table_value_type=self.type + ) def select(self): """Produce a :func:`_expression.select` construct @@ -351,6 +551,14 @@ class FunctionElement(Executable, ColumnElement, FromClause): s = s.execution_options(**self._execution_options) return s + @util.deprecated_20( + ":meth:`.FunctionElement.scalar`", + alternative="Scalar execution in SQLAlchemy 2.0 is performed " + "by the :meth:`_engine.Connection.scalar` method of " + ":class:`_engine.Connection`, " + "or in the ORM by the :meth:`.Session.scalar` method of " + ":class:`.Session`.", + ) def scalar(self): """Execute this :class:`.FunctionElement` against an embedded 'bind' and return a scalar value. @@ -365,6 +573,14 @@ class FunctionElement(Executable, ColumnElement, FromClause): """ return self.select().execute().scalar() + @util.deprecated_20( + ":meth:`.FunctionElement.execute`", + alternative="All statement execution in SQLAlchemy 2.0 is performed " + "by the :meth:`_engine.Connection.execute` method of " + ":class:`_engine.Connection`, " + "or in the ORM by the :meth:`.Session.execute` method of " + ":class:`.Session`.", + ) def execute(self): """Execute this :class:`.FunctionElement` against an embedded 'bind'. @@ -441,6 +657,24 @@ class FunctionAsBinary(BinaryExpression): self.sql_function.clauses.clauses[self.right_index - 1] = value +class ScalarFunctionColumn(NamedColumn): + __visit_name__ = "scalar_function_column" + + _traverse_internals = [ + ("name", InternalTraversal.dp_anon_name), + ("type", InternalTraversal.dp_type), + ("fn", InternalTraversal.dp_clauseelement), + ] + + is_literal = False + table = None + + def __init__(self, fn, name, type_=None): + self.fn = fn + self.name = name + self.type = sqltypes.to_instance(type_) + + class _FunctionGenerator(object): """Generate SQL function expressions. @@ -586,10 +820,9 @@ class Function(FunctionElement): func.mypackage.some_function(col1, col2) - .. seealso:: - :ref:`coretutorial_functions` + :ref:`tutorial_functions` - in the :ref:`unified_tutorial` :data:`.func` - namespace which produces registered or ad-hoc :class:`.Function` instances. @@ -607,6 +840,23 @@ class Function(FunctionElement): ("type", InternalTraversal.dp_type), ] + type = sqltypes.NULLTYPE + """A :class:`_types.TypeEngine` object which refers to the SQL return + type represented by this SQL function. + + This datatype may be configured when generating a + :class:`_functions.Function` object by passing the + :paramref:`_functions.Function.type_` parameter, e.g.:: + + >>> select(func.lower("some VALUE", type_=String)) + + The small number of built-in classes of :class:`_functions.Function` come + with a built-in datatype that's appropriate to the class of function and + its arguments. For functions that aren't known, the type defaults to the + "null type". + + """ + @util.deprecated_params( bind=( "2.0", @@ -825,6 +1075,8 @@ class next_value(GenericFunction): class AnsiFunction(GenericFunction): + """Define a function in "ansi" format, which doesn't render parenthesis.""" + inherit_cache = True def __init__(self, *args, **kwargs): @@ -856,29 +1108,61 @@ class coalesce(ReturnTypeFromArgs): inherit_cache = True -class max(ReturnTypeFromArgs): # noqa +class max(ReturnTypeFromArgs): # noqa A001 + """The SQL MAX() aggregate function.""" + inherit_cache = True -class min(ReturnTypeFromArgs): # noqa +class min(ReturnTypeFromArgs): # noqa A001 + """The SQL MIN() aggregate function.""" + inherit_cache = True -class sum(ReturnTypeFromArgs): # noqa +class sum(ReturnTypeFromArgs): # noqa A001 + """The SQL SUM() aggregate function.""" + inherit_cache = True -class now(GenericFunction): # noqa +class now(GenericFunction): + """The SQL now() datetime function. + + SQLAlchemy dialects will usually render this particular function + in a backend-specific way, such as rendering it as ``CURRENT_TIMESTAMP``. + + """ + type = sqltypes.DateTime inherit_cache = True class concat(GenericFunction): + """The SQL CONCAT() function, which concatenates strings. + + E.g.:: + + >>> print(select(func.concat('a', 'b'))) + SELECT concat(:concat_2, :concat_3) AS concat_1 + + String concatenation in SQLAlchemy is more commonly available using the + Python ``+`` operator with string datatypes, which will render a + backend-specific concatenation operator, such as :: + + >>> print(select(literal("a") + "b")) + SELECT :param_1 || :param_2 AS anon_1 + + + """ + type = sqltypes.String inherit_cache = True class char_length(GenericFunction): + """The CHAR_LENGTH() SQL function.""" + type = sqltypes.Integer inherit_cache = True @@ -887,6 +1171,8 @@ class char_length(GenericFunction): class random(GenericFunction): + """The RANDOM() SQL function.""" + _has_args = True inherit_cache = True @@ -922,46 +1208,64 @@ class count(GenericFunction): class current_date(AnsiFunction): + """The CURRENT_DATE() SQL function.""" + type = sqltypes.Date inherit_cache = True class current_time(AnsiFunction): + """The CURRENT_TIME() SQL function.""" + type = sqltypes.Time inherit_cache = True class current_timestamp(AnsiFunction): + """The CURRENT_TIMESTAMP() SQL function.""" + type = sqltypes.DateTime inherit_cache = True class current_user(AnsiFunction): + """The CURRENT_USER() SQL function.""" + type = sqltypes.String inherit_cache = True class localtime(AnsiFunction): + """The localtime() SQL function.""" + type = sqltypes.DateTime inherit_cache = True class localtimestamp(AnsiFunction): + """The localtimestamp() SQL function.""" + type = sqltypes.DateTime inherit_cache = True class session_user(AnsiFunction): + """The SESSION_USER() SQL function.""" + type = sqltypes.String inherit_cache = True class sysdate(AnsiFunction): + """The SYSDATE() SQL function.""" + type = sqltypes.DateTime inherit_cache = True class user(AnsiFunction): + """The USER() SQL function.""" + type = sqltypes.String inherit_cache = True diff --git a/lib/sqlalchemy/sql/roles.py b/lib/sqlalchemy/sql/roles.py index 2c4ff75c4..52743bd50 100644 --- a/lib/sqlalchemy/sql/roles.py +++ b/lib/sqlalchemy/sql/roles.py @@ -44,6 +44,10 @@ class ColumnArgumentOrKeyRole(ColumnArgumentRole): _role_name = "Column expression or string key" +class StrAsPlainColumnRole(ColumnArgumentRole): + _role_name = "Column expression or string key" + + class ColumnListRole(SQLRole): """Elements suitable for forming comma separated lists of expressions.""" diff --git a/lib/sqlalchemy/sql/selectable.py b/lib/sqlalchemy/sql/selectable.py index 1bd4f5d81..a273e0c90 100644 --- a/lib/sqlalchemy/sql/selectable.py +++ b/lib/sqlalchemy/sql/selectable.py @@ -51,6 +51,7 @@ from .elements import ColumnClause from .elements import GroupedElement from .elements import Grouping from .elements import literal_column +from .elements import TableValuedColumn from .elements import UnaryExpression from .visitors import InternalTraversal from .. import exc @@ -623,6 +624,34 @@ class FromClause(roles.AnonymizedFromClauseRole, Selectable): return Alias._construct(self, name) + @util.preload_module("sqlalchemy.sql.sqltypes") + def table_valued(self): + """Return a :class:`_sql.TableValuedColumn` object for this + :class:`_expression.FromClause`. + + A :class:`_sql.TableValuedColumn` is a :class:`_sql.ColumnElement` that + represents a complete row in a table. Support for this construct is + backend dependent, and is supported in various forms by backends + such as PostgreSQL, Oracle and SQL Server. + + E.g.:: + + >>> from sqlalchemy import select, column, func, table + >>> a = table("a", column("id"), column("x"), column("y")) + >>> stmt = select(func.row_to_json(a.table_valued())) + >>> print(stmt) + SELECT row_to_json(a) AS row_to_json_1 + FROM a + + .. versionadded:: 1.4.0b2 + + .. seealso:: + + :ref:`tutorial_functions` - in the :ref:`unified_tutorial` + + """ + return TableValuedColumn(self, type_api.TABLEVALUE) + def tablesample(self, sampling, name=None, seed=None): """Return a TABLESAMPLE alias of this :class:`_expression.FromClause`. @@ -1519,6 +1548,8 @@ class AliasedReturnsRows(NoInit, FromClause): _is_from_container = True named_with_column = True + _supports_derived_columns = False + _traverse_internals = [ ("element", InternalTraversal.dp_clauseelement), ("name", InternalTraversal.dp_anon_name), @@ -1678,6 +1709,151 @@ class Alias(roles.DMLTableRole, AliasedReturnsRows): ).alias(name=name, flat=flat) +class TableValuedAlias(Alias): + """An alias against a "table valued" SQL function. + + This construct provides for a SQL function that returns columns + to be used in the FROM clause of a SELECT statement. The + object is generated using the :meth:`_functions.FunctionElement.table_valued` + method, e.g.:: + + >>> from sqlalchemy import select, func + >>> fn = func.json_array_elements_text('["one", "two", "three"]').table_valued("value") + >>> print(select(fn.c.value)) + SELECT anon_1.value + FROM json_array_elements_text(:json_array_elements_text_1) AS anon_1 + + .. versionadded:: 1.4.0b2 + + .. seealso:: + + :ref:`tutorial_functions_table_valued` - in the :ref:`unified_tutorial` + + """ # noqa E501 + + __visit_name__ = "table_valued_alias" + + _supports_derived_columns = True + _render_derived = False + _render_derived_w_types = False + + _traverse_internals = [ + ("element", InternalTraversal.dp_clauseelement), + ("name", InternalTraversal.dp_anon_name), + ("_tableval_type", InternalTraversal.dp_type), + ("_render_derived", InternalTraversal.dp_boolean), + ("_render_derived_w_types", InternalTraversal.dp_boolean), + ] + + def _init(self, selectable, name=None, table_value_type=None): + super(TableValuedAlias, self)._init(selectable, name=name) + + self._tableval_type = ( + type_api.TABLEVALUE + if table_value_type is None + else table_value_type + ) + + @HasMemoized.memoized_attribute + def column(self): + """Return a column expression representing this + :class:`_sql.TableValuedAlias`. + + This accessor is used to implement the + :meth:`_functions.FunctionElement.column_valued` method. See that + method for further details. + + E.g.:: + + >>> print(select(func.some_func().table_valued("value").column)) + SELECT anon_1 FROM some_func() AS anon_1 + + .. seealso:: + + :meth:`_functions.FunctionElement.column_valued` + + """ + + return TableValuedColumn(self, self._tableval_type) + + def alias(self, name=None): + """Return a new alias of this :class:`_sql.TableValuedAlias`. + + This creates a distinct FROM object that will be distinguished + from the original one when used in a SQL statement. + + """ + + tva = TableValuedAlias._construct(self, name=name) + if self._render_derived: + tva._render_derived = True + tva._render_derived_w_types = self._render_derived_w_types + return tva + + def lateral(self, name=None): + """Return a new :class:`_sql.TableValuedAlias` with the lateral flag set, + so that it renders as LATERAL. + + .. seealso:: + + :func:`_expression.lateral` + + """ + tva = self.alias(name=name) + tva._is_lateral = True + return tva + + def render_derived(self, name=None, with_types=False): + """Apply "render derived" to this :class:`_sql.TableValuedAlias`. + + This has the effect of the individual column names listed out + after the alias name in the "AS" sequence, e.g.:: + + >>> print( + ... select( + ... func.unnest(array(["one", "two", "three"])). + table_valued("x", with_ordinality="o").render_derived() + ... ) + ... ) + SELECT anon_1.x, anon_1.o + FROM unnest(ARRAY[%(param_1)s, %(param_2)s, %(param_3)s]) WITH ORDINALITY AS anon_1(x, o) + + The ``with_types`` keyword will render column types inline within + the alias expression (this syntax currently applies to the + PostgreSQL database):: + + >>> print( + ... select( + ... func.json_to_recordset( + ... '[{"a":1,"b":"foo"},{"a":"2","c":"bar"}]' + ... ) + ... .table_valued(column("a", Integer), column("b", String)) + ... .render_derived(with_types=True) + ... ) + ... ) + SELECT anon_1.a, anon_1.b FROM json_to_recordset(:json_to_recordset_1) + AS anon_1(a INTEGER, b VARCHAR) + + :param name: optional string name that will be applied to the alias + generated. If left as None, a unique anonymizing name will be used. + + :param with_types: if True, the derived columns will include the + datatype specification with each column. This is a special syntax + currently known to be required by PostgreSQL for some SQL functions. + + """ # noqa E501 + + # note: don't use the @_generative system here, keep a reference + # to the original object. otherwise you can have re-use of the + # python id() of the original which can cause name conflicts if + # a new anon-name grabs the same identifier as the local anon-name + # (just saw it happen on CI) + new_alias = TableValuedAlias._construct(self, name=name) + new_alias._render_derived = True + new_alias._render_derived_w_types = with_types + return new_alias + + class Lateral(AliasedReturnsRows): """Represent a LATERAL subquery. @@ -2473,7 +2649,7 @@ class Values(Generative, FromClause): value_expr = values( column('id', Integer), - column('name', Integer), + column('name', String), name="my_values" ).data( [(1, 'name1'), (2, 'name2'), (3, 'name3')] diff --git a/lib/sqlalchemy/sql/sqltypes.py b/lib/sqlalchemy/sql/sqltypes.py index d20c8168d..3484b3ac8 100644 --- a/lib/sqlalchemy/sql/sqltypes.py +++ b/lib/sqlalchemy/sql/sqltypes.py @@ -26,6 +26,8 @@ from .elements import _defer_name from .elements import quoted_name from .elements import Slice from .elements import TypeCoerce as type_coerce # noqa +from .traversals import HasCacheKey +from .traversals import InternalTraversal from .type_api import Emulated from .type_api import NativeForEmulated # noqa from .type_api import to_instance @@ -2049,17 +2051,18 @@ class JSON(Indexable, TypeEngine): JSON types. Since it supports JSON SQL operations, it only works on backends that have an actual JSON type, currently: - * PostgreSQL - see :class:`_postgresql.JSON` and - :class:`_postgresql.JSONB` for backend-specific notes + * PostgreSQL - see :class:`sqlalchemy.dialects.postgresql.JSON` and + :class:`sqlalchemy.dialects.postgresql.JSONB` for backend-specific + notes - * MySQL as of version 5.7 (MariaDB as of the 10.2 series does not) - see - :class:`_mysql.JSON` for backend-specific notes + * MySQL - see + :class:`sqlalchemy.dialects.mysql.JSON` for backend-specific notes - * SQLite as of version 3.9 - see :class:`_sqlite.JSON` for - backend-specific notes + * SQLite as of version 3.9 - see + :class:`sqlalchemy.dialects.sqlite.JSON` for backend-specific notes - * Microsoft SQL Server 2016 and later - see :class:`_mssql.JSON` for - backend-specific notes + * Microsoft SQL Server 2016 and later - see + :class:`sqlalchemy.dialects.mssql.JSON` for backend-specific notes :class:`_types.JSON` is part of the Core in support of the growing popularity of native JSON datatypes. @@ -2102,9 +2105,10 @@ class JSON(Indexable, TypeEngine): .. versionadded:: 1.3.11 Additional operations may be available from the dialect-specific versions - of :class:`_types.JSON`, such as :class:`_postgresql.JSON` and - :class:`_postgresql.JSONB` which both offer additional PostgreSQL-specific - operations. + of :class:`_types.JSON`, such as + :class:`sqlalchemy.dialects.postgresql.JSON` and + :class:`sqlalchemy.dialects.postgresql.JSONB` which both offer additional + PostgreSQL-specific operations. **Casting JSON Elements to Other Types** @@ -2219,13 +2223,13 @@ class JSON(Indexable, TypeEngine): .. seealso:: - :class:`_postgresql.JSON` + :class:`sqlalchemy.dialects.postgresql.JSON` - :class:`_postgresql.JSONB` + :class:`sqlalchemy.dialects.postgresql.JSONB` - :class:`.mysql.JSON` + :class:`sqlalchemy.dialects.mysql.JSON` - :class:`_sqlite.JSON` + :class:`sqlalchemy.dialects.sqlite.JSON` .. versionadded:: 1.1 @@ -2579,11 +2583,11 @@ class ARRAY(SchemaEventTarget, Indexable, Concatenable, TypeEngine): """Represent a SQL Array type. .. note:: This type serves as the basis for all ARRAY operations. - However, currently **only the PostgreSQL backend has support - for SQL arrays in SQLAlchemy**. It is recommended to use the - :class:`_postgresql.ARRAY` type directly when using ARRAY types - with PostgreSQL, as it provides additional operators specific - to that backend. + However, currently **only the PostgreSQL backend has support for SQL + arrays in SQLAlchemy**. It is recommended to use the PostgreSQL-specific + :class:`sqlalchemy.dialects.postgresql.ARRAY` type directly when using + ARRAY types with PostgreSQL, as it provides additional operators + specific to that backend. :class:`_types.ARRAY` is part of the Core in support of various SQL standard functions such as :class:`_functions.array_agg` @@ -2665,7 +2669,7 @@ class ARRAY(SchemaEventTarget, Indexable, Concatenable, TypeEngine): .. seealso:: - :class:`_postgresql.ARRAY` + :class:`sqlalchemy.dialects.postgresql.ARRAY` """ @@ -3110,6 +3114,22 @@ class NullType(TypeEngine): comparator_factory = Comparator +class TableValueType(HasCacheKey, TypeEngine): + """Refers to a table value type.""" + + _is_table_value = True + + _traverse_internals = [ + ("_elements", InternalTraversal.dp_clauseelement_list), + ] + + def __init__(self, *elements): + self._elements = [ + coercions.expect(roles.StrAsPlainColumnRole, elem) + for elem in elements + ] + + class MatchType(Boolean): """Refers to the return type of the MATCH operator. @@ -3131,6 +3151,7 @@ BOOLEANTYPE = Boolean() STRINGTYPE = String() INTEGERTYPE = Integer() MATCHTYPE = MatchType() +TABLEVALUE = TableValueType() _type_map = { int: Integer(), @@ -3183,5 +3204,6 @@ type_api.INTEGERTYPE = INTEGERTYPE type_api.NULLTYPE = NULLTYPE type_api.MATCHTYPE = MATCHTYPE type_api.INDEXABLE = Indexable +type_api.TABLEVALUE = TABLEVALUE type_api._resolve_value_to_type = _resolve_value_to_type TypeEngine.Comparator.BOOLEANTYPE = BOOLEANTYPE diff --git a/lib/sqlalchemy/sql/traversals.py b/lib/sqlalchemy/sql/traversals.py index 2887813ad..51a531000 100644 --- a/lib/sqlalchemy/sql/traversals.py +++ b/lib/sqlalchemy/sql/traversals.py @@ -857,7 +857,10 @@ class _GetChildren(InternalTraversal): with a _traverse_internals collection.""" def visit_has_cache_key(self, element, **kw): - return (element,) + # the GetChildren traversal refers explicitly to ClauseElement + # structures. Within these, a plain HasCacheKey is not a + # ClauseElement, so don't include these. + return () def visit_clauseelement(self, element, **kw): return (element,) diff --git a/lib/sqlalchemy/sql/type_api.py b/lib/sqlalchemy/sql/type_api.py index 462a8763b..46751cb22 100644 --- a/lib/sqlalchemy/sql/type_api.py +++ b/lib/sqlalchemy/sql/type_api.py @@ -24,6 +24,7 @@ NULLTYPE = None STRINGTYPE = None MATCHTYPE = None INDEXABLE = None +TABLEVALUE = None _resolve_value_to_type = None @@ -45,6 +46,7 @@ class TypeEngine(Traversible): _sqla_type = True _isnull = False _is_tuple_type = False + _is_table_value = False class Comparator(operators.ColumnOperators): """Base class for custom comparison operations defined at the diff --git a/lib/sqlalchemy/sql/visitors.py b/lib/sqlalchemy/sql/visitors.py index fe0fbf669..8e113849e 100644 --- a/lib/sqlalchemy/sql/visitors.py +++ b/lib/sqlalchemy/sql/visitors.py @@ -75,10 +75,8 @@ def _generate_compiler_dispatch(cls): try: meth = getter(visitor) except AttributeError as err: - util.raise_( - exc.UnsupportedCompilationError(visitor, cls), - replace_context=err, - ) + return visitor.visit_unsupported_compilation(self, err, **kw) + else: return meth(self, **kw) diff --git a/lib/sqlalchemy/testing/requirements.py b/lib/sqlalchemy/testing/requirements.py index f5286c85d..d8da9c818 100644 --- a/lib/sqlalchemy/testing/requirements.py +++ b/lib/sqlalchemy/testing/requirements.py @@ -57,6 +57,18 @@ class SuiteRequirements(Requirements): return exclusions.open() + @property + def table_value_constructor(self): + """Database / dialect supports a query like:: + + SELECT * FROM VALUES ( (c1, c2), (c1, c2), ...) + AS some_table(col1, col2) + + SQLAlchemy generates this with the :func:`_sql.values` function. + + """ + return exclusions.closed() + @property def standard_cursor_sql(self): """Target database passes SQL-92 style statements to cursor.execute() diff --git a/lib/sqlalchemy/testing/suite/test_select.py b/lib/sqlalchemy/testing/suite/test_select.py index 0d9f08848..c6dacd423 100644 --- a/lib/sqlalchemy/testing/suite/test_select.py +++ b/lib/sqlalchemy/testing/suite/test_select.py @@ -32,6 +32,7 @@ from ... import true from ... import tuple_ from ... import union from ... import util +from ... import values from ...exc import DatabaseError from ...exc import ProgrammingError @@ -151,6 +152,22 @@ class OrderByLabelTest(fixtures.TablesTest): self._assert_result(stmt, [(1, 3), (1, 5), (1, 7)]) +class ValuesExpressionTest(fixtures.TestBase): + __requires__ = ("table_value_constructor",) + + __backend__ = True + + def test_tuples(self, connection): + value_expr = values( + column("id", Integer), column("name", String), name="my_values" + ).data([(1, "name1"), (2, "name2"), (3, "name3")]) + + eq_( + connection.execute(select(value_expr)).all(), + [(1, "name1"), (2, "name2"), (3, "name3")], + ) + + class FetchLimitOffsetTest(fixtures.TablesTest): __backend__ = True -- cgit v1.2.1