From: Mike Bayer Date: Sat, 24 Sep 2011 01:56:10 +0000 (-0400) Subject: - The behavior of =/!= when comparing a scalar select X-Git-Tag: rel_0_7_3~32 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=c52e31b1e019fb447e0a2edb7e2c75ebe9307a95;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git - The behavior of =/!= when comparing a scalar select to a value will no longer produce IN/NOT IN as of 0.8; this behavior is a little too heavy handed (use in_() if you want to emit IN) and now emits a deprecation warning. To get the 0.8 behavior immediately and remove the warning, a compiler recipe is given at http://www.sqlalchemy.org/docs/07/dialects/mssql.html#scalar-select-comparisons to override the behavior of visit_binary(). [ticket:2277] --- diff --git a/CHANGES b/CHANGES index 1f5cd15bda..56d9140d7e 100644 --- a/CHANGES +++ b/CHANGES @@ -206,6 +206,16 @@ CHANGES on OSX, MemoryErrors abound and just plain broken unicode support. [ticket:2273] + - The behavior of =/!= when comparing a scalar select + to a value will no longer produce IN/NOT IN as of 0.8; + this behavior is a little too heavy handed (use in_() if + you want to emit IN) and now emits a deprecation warning. + To get the 0.8 behavior immediately and remove the warning, + a compiler recipe is given at + http://www.sqlalchemy.org/docs/07/dialects/mssql.html#scalar-select-comparisons + to override the behavior of visit_binary(). + [ticket:2277] + - "0" is accepted as an argument for limit() which will produce "TOP 0". [ticket:2222] diff --git a/lib/sqlalchemy/dialects/mssql/base.py b/lib/sqlalchemy/dialects/mssql/base.py index 981ffc2384..c7e1a540a1 100644 --- a/lib/sqlalchemy/dialects/mssql/base.py +++ b/lib/sqlalchemy/dialects/mssql/base.py @@ -157,7 +157,30 @@ following ALTER DATABASE commands executed at the SQL prompt:: Background on SQL Server snapshot isolation is available at http://msdn.microsoft.com/en-us/library/ms175095.aspx. - + +Scalar Select Comparisons +------------------------- + +The MSSQL dialect contains a legacy behavior whereby comparing +a scalar select to a value using the ``=`` or ``!=`` operator +will resolve to IN or NOT IN, respectively. This behavior is +deprecated and will be removed in 0.8 - the ``s.in_()``/``~s.in_()`` operators +should be used when IN/NOT IN are desired. + +For the time being, the existing behavior prevents a comparison +between scalar select and another value that actually wants to use ``=``. +To remove this behavior in a forwards-compatible way, apply this +compilation rule by placing the following code at the module import +level:: + + from sqlalchemy.ext.compiler import compiles + from sqlalchemy.sql.expression import _BinaryExpression + from sqlalchemy.sql.compiler import SQLCompiler + + @compiles(_BinaryExpression, 'mssql') + def override_legacy_binary(element, compiler, **kw): + return SQLCompiler.visit_binary(compiler, element, **kw) + Known Issues ------------ @@ -889,6 +912,10 @@ class MSSQLCompiler(compiler.SQLCompiler): ) ): op = binary.operator == operator.eq and "IN" or "NOT IN" + util.warn_deprecated("Comparing a scalar select using ``=``/``!=`` will " + "no longer produce IN/NOT IN in 0.8. To remove this " + "behavior immediately, use the recipe at " + "http://www.sqlalchemy.org/docs/07/dialects/mssql.html#scalar-select-comparisons") return self.process( expression._BinaryExpression(binary.left, binary.right, op), diff --git a/test/dialect/test_mssql.py b/test/dialect/test_mssql.py index 4cce395b8e..f336f5f3b3 100644 --- a/test/dialect/test_mssql.py +++ b/test/dialect/test_mssql.py @@ -63,6 +63,7 @@ class CompileTest(fixtures.TestBase, AssertsCompiledSQL): ]: self.assert_compile(expr, compile, dialect=mxodbc_dialect) + @testing.uses_deprecated def test_in_with_subqueries(self): """Test that when using subqueries in a binary expression the == and != are changed to IN and NOT IN respectively. @@ -117,7 +118,7 @@ class CompileTest(fixtures.TestBase, AssertsCompiledSQL): 'DELETE FROM paj.test WHERE paj.test.id = ' ':id_1') s = select([tbl.c.id]).where(tbl.c.id == 1) - self.assert_compile(tbl.delete().where(tbl.c.id == s), + self.assert_compile(tbl.delete().where(tbl.c.id.in_(s)), 'DELETE FROM paj.test WHERE paj.test.id IN ' '(SELECT test_1.id FROM paj.test AS test_1 ' 'WHERE test_1.id = :id_1)') @@ -130,7 +131,7 @@ class CompileTest(fixtures.TestBase, AssertsCompiledSQL): 'DELETE FROM banana.paj.test WHERE ' 'banana.paj.test.id = :id_1') s = select([tbl.c.id]).where(tbl.c.id == 1) - self.assert_compile(tbl.delete().where(tbl.c.id == s), + self.assert_compile(tbl.delete().where(tbl.c.id.in_(s)), 'DELETE FROM banana.paj.test WHERE ' 'banana.paj.test.id IN (SELECT test_1.id ' 'FROM banana.paj.test AS test_1 WHERE ' @@ -144,7 +145,7 @@ class CompileTest(fixtures.TestBase, AssertsCompiledSQL): 'DELETE FROM [banana split].paj.test WHERE ' '[banana split].paj.test.id = :id_1') s = select([tbl.c.id]).where(tbl.c.id == 1) - self.assert_compile(tbl.delete().where(tbl.c.id == s), + self.assert_compile(tbl.delete().where(tbl.c.id.in_(s)), 'DELETE FROM [banana split].paj.test WHERE ' '[banana split].paj.test.id IN (SELECT ' 'test_1.id FROM [banana split].paj.test AS ' @@ -160,7 +161,7 @@ class CompileTest(fixtures.TestBase, AssertsCompiledSQL): 'space].test WHERE [banana split].[paj ' 'with a space].test.id = :id_1') s = select([tbl.c.id]).where(tbl.c.id == 1) - self.assert_compile(tbl.delete().where(tbl.c.id == s), + self.assert_compile(tbl.delete().where(tbl.c.id.in_(s)), 'DELETE FROM [banana split].[paj with a ' 'space].test WHERE [banana split].[paj ' 'with a space].test.id IN (SELECT ' diff --git a/test/orm/inheritance/test_query.py b/test/orm/inheritance/test_query.py index 94dde71f84..935af12c8a 100644 --- a/test/orm/inheritance/test_query.py +++ b/test/orm/inheritance/test_query.py @@ -753,7 +753,7 @@ def _produce_test(select_type): # the subquery and usually results in recursion overflow errors within the adaption. subq = sess.query(engineers.c.person_id).filter(Engineer.primary_language=='java').statement.as_scalar() - eq_(sess.query(Person).filter(Person.person_id==subq).one(), e1) + eq_(sess.query(Person).filter(Person.person_id.in_(subq)).one(), e1) def test_mixed_entities(self): sess = create_session() diff --git a/test/orm/test_eager_relations.py b/test/orm/test_eager_relations.py index 4347194861..d1e4535bd3 100644 --- a/test/orm/test_eager_relations.py +++ b/test/orm/test_eager_relations.py @@ -10,6 +10,7 @@ from sqlalchemy import Integer, String, Date, ForeignKey, and_, select, \ from test.lib.schema import Table, Column from sqlalchemy.orm import mapper, relationship, create_session, \ lazyload, aliased, column_property +from sqlalchemy.sql import operators from test.lib.testing import eq_, assert_raises, \ assert_raises_message from test.lib.assertsql import CompiledSQL @@ -2539,18 +2540,20 @@ class CorrelatedSubqueryTest(fixtures.MappedTest): stuff_view = select([salias.c.id]).where(salias.c.user_id==users.c.id).\ correlate(users).order_by(salias.c.date.desc()).limit(1) + operator = operators.in_op if labeled == 'label': stuff_view = stuff_view.label('foo') + operator = operators.eq elif labeled == 'scalar': stuff_view = stuff_view.as_scalar() if ondate: mapper(User, users, properties={ - 'stuff':relationship(Stuff, primaryjoin=and_(users.c.id==stuff.c.user_id, stuff.c.date==stuff_view)) + 'stuff':relationship(Stuff, primaryjoin=and_(users.c.id==stuff.c.user_id, operator(stuff.c.date, stuff_view))) }) else: mapper(User, users, properties={ - 'stuff':relationship(Stuff, primaryjoin=and_(users.c.id==stuff.c.user_id, stuff.c.id==stuff_view)) + 'stuff':relationship(Stuff, primaryjoin=and_(users.c.id==stuff.c.user_id, operator(stuff.c.id, stuff_view))) }) sess = create_session() diff --git a/test/orm/test_query.py b/test/orm/test_query.py index 39a9b5137d..fc3bb44222 100644 --- a/test/orm/test_query.py +++ b/test/orm/test_query.py @@ -836,7 +836,7 @@ class ExpressionTest(QueryTest, AssertsCompiledSQL): 'IN (SELECT users.id FROM users WHERE ' 'users.id = :id_1)') - + @testing.fails_on('mssql', "mssql doesn't allow col = , sqla deprecated workaround") def test_param_transfer(self): User = self.classes.User