- The :meth:`.PGDialect.has_table` method will now query against

``pg_catalog.pg_table_is_visible(c.oid)``, rather than testing
for an exact schema match, when the schema name is None; this
so that the method will also illustrate that temporary tables
are present.  Note that this is a behavioral change, as Postgresql
allows a non-temporary table to silently overwrite an existing
temporary table of the same name, so this changes the behavior
of ``checkfirst`` in that unusual scenario.
fixes #3264

diff --git a/doc/build/changelog/changelog_10.rst b/doc/build/changelog/changelog_10.rst
index f2bd43a76b5c3b0e37f60617b87cba38fbbed809..ad9eefa09b216706c33ca6173b970d68bb61c6b9 100644 (file)
--- a/doc/build/changelog/changelog_10.rst
+++ b/doc/build/changelog/changelog_10.rst
@@ -21,6 +21,23 @@
     series as well.  For changes that are specific to 1.0 with an emphasis
     on compatibility concerns, see :doc:`/changelog/migration_10`.
 
+    .. change::
+        :tags: bug, postgresql
+        :tickets: 3264
+
+        The :meth:`.PGDialect.has_table` method will now query against
+        ``pg_catalog.pg_table_is_visible(c.oid)``, rather than testing
+        for an exact schema match, when the schema name is None; this
+        so that the method will also illustrate that temporary tables
+        are present.  Note that this is a behavioral change, as Postgresql
+        allows a non-temporary table to silently overwrite an existing
+        temporary table of the same name, so this changes the behavior
+        of ``checkfirst`` in that unusual scenario.
+
+        .. seealso::
+
+            :ref:`change_3264`
+
     .. change::
         :tags: bug, sql
         :tickets: 3260

diff --git a/doc/build/changelog/migration_10.rst b/doc/build/changelog/migration_10.rst
index c4157266bb4185a4a2661da0068bb01dcc81db6f..e148e7d70cf4850833d19ae76d32cae104285a32 100644 (file)
--- a/doc/build/changelog/migration_10.rst
+++ b/doc/build/changelog/migration_10.rst
@@ -276,6 +276,64 @@ running 0.9 in production.
 
 :ticket:`2891`
 
+.. _change_3264:
+
+Postgresql ``has_table()`` now works for temporary tables
+---------------------------------------------------------
+
+This is a simple fix such that "has table" for temporary tables now works,
+so that code like the following may proceed::
+
+    from sqlalchemy import *
+
+    metadata = MetaData()
+    user_tmp = Table(
+        "user_tmp", metadata,
+        Column("id", INT, primary_key=True),
+        Column('name', VARCHAR(50)),
+        prefixes=['TEMPORARY']
+    )
+
+    e = create_engine("postgresql://scott:tiger@localhost/test", echo='debug')
+    with e.begin() as conn:
+        user_tmp.create(conn, checkfirst=True)
+
+        # checkfirst will succeed
+        user_tmp.create(conn, checkfirst=True)
+
+The very unlikely case that this behavior will cause a non-failing application
+to behave differently, is because Postgresql allows a non-temporary table
+to silently overwrite a temporary table.  So code like the following will
+now act completely differently, no longer creating the real table following
+the temporary table::
+
+    from sqlalchemy import *
+
+    metadata = MetaData()
+    user_tmp = Table(
+        "user_tmp", metadata,
+        Column("id", INT, primary_key=True),
+        Column('name', VARCHAR(50)),
+        prefixes=['TEMPORARY']
+    )
+
+    e = create_engine("postgresql://scott:tiger@localhost/test", echo='debug')
+    with e.begin() as conn:
+        user_tmp.create(conn, checkfirst=True)
+
+        m2 = MetaData()
+        user = Table(
+            "user_tmp", m2,
+            Column("id", INT, primary_key=True),
+            Column('name', VARCHAR(50)),
+        )
+
+        # in 0.9, *will create* the new table, overwriting the old one.
+        # in 1.0, *will not create* the new table
+        user.create(conn, checkfirst=True)
+
+:ticket:`3264`
+
 .. _feature_gh134:
 
 Postgresql FILTER keyword

diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py
index baa640eaadd4227ba4722f4a89bd1b535cf1e61f..034ee90768b913f1cbc223c1051406e0142aa284 100644 (file)
--- a/lib/sqlalchemy/dialects/postgresql/base.py
+++ b/lib/sqlalchemy/dialects/postgresql/base.py
@@ -1942,7 +1942,8 @@ class PGDialect(default.DefaultDialect):
             cursor = connection.execute(
                 sql.text(
                     "select relname from pg_class c join pg_namespace n on "
-                    "n.oid=c.relnamespace where n.nspname=current_schema() "
+                    "n.oid=c.relnamespace where "
+                    "pg_catalog.pg_table_is_visible(c.oid) "
                     "and relname=:name",
                     bindparams=[
                         sql.bindparam('name', util.text_type(table_name),

diff --git a/lib/sqlalchemy/testing/suite/test_reflection.py b/lib/sqlalchemy/testing/suite/test_reflection.py
index 08b858b472850f302c9b4f788c5522efc14880d7..e58b6f068d19deff53b3307d35e0134c0f3c6e01 100644 (file)
--- a/lib/sqlalchemy/testing/suite/test_reflection.py
+++ b/lib/sqlalchemy/testing/suite/test_reflection.py
@@ -128,6 +128,10 @@ class ComponentReflectionTest(fixtures.TablesTest):
                 DDL("create temporary view user_tmp_v as "
                     "select * from user_tmp")
             )
+            event.listen(
+                user_tmp, "before_drop",
+                DDL("drop view user_tmp_v")
+            )
 
     @classmethod
     def define_index(cls, metadata, users):

diff --git a/test/dialect/postgresql/test_reflection.py b/test/dialect/postgresql/test_reflection.py
index 8de71216e816d1d79e8141e31290435b6526124b..0dda1fa452b7dc20b571b070c6f45cd47c7994c7 100644 (file)
--- a/test/dialect/postgresql/test_reflection.py
+++ b/test/dialect/postgresql/test_reflection.py
@@ -322,6 +322,18 @@ class ReflectionTest(fixtures.TestBase):
         t2 = Table('t', m2, autoload=True)
         eq_([c.name for c in t2.primary_key], ['t_id'])
 
+    @testing.provide_metadata
+    def test_has_temporary_table(self):
+        assert not testing.db.has_table("some_temp_table")
+        user_tmp = Table(
+            "some_temp_table", self.metadata,
+            Column("id", Integer, primary_key=True),
+            Column('name', String(50)),
+            prefixes=['TEMPORARY']
+        )
+        user_tmp.create(testing.db)
+        assert testing.db.has_table("some_temp_table")
+
     @testing.provide_metadata
     def test_cross_schema_reflection_one(self):