- Fixed issue where a primary key column that has a Sequence on it,

yet the column is not the "auto increment" column, either because
it has a foreign key constraint or ``autoincrement=False`` set,
would attempt to fire the Sequence on INSERT for backends that don't
support sequences, when presented with an INSERT missing the primary
key value.  This would take place on non-sequence backends like
SQLite, MySQL. [ticket:2896]

diff --git a/doc/build/changelog/changelog_08.rst b/doc/build/changelog/changelog_08.rst
index 5b6a99f3eb4eb01b0c30a63c1e3cf577b0603ae8..08f8314c54d846e29578d845d83d3668c77ff5bf 100644 (file)
--- a/doc/build/changelog/changelog_08.rst
+++ b/doc/build/changelog/changelog_08.rst
@@ -11,6 +11,19 @@
 .. changelog::
     :version: 0.8.5
 
+    .. change::
+        :tags: bug, sql
+        :versions: 0.9.0b2
+        :tickets: 2896
+
+        Fixed issue where a primary key column that has a Sequence on it,
+        yet the column is not the "auto increment" column, either because
+        it has a foreign key constraint or ``autoincrement=False`` set,
+        would attempt to fire the Sequence on INSERT for backends that don't
+        support sequences, when presented with an INSERT missing the primary
+        key value.  This would take place on non-sequence backends like
+        SQLite, MySQL.
+
     .. change::
         :tags: bug, sql
         :versions: 0.9.0b2

diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index 608023f5172c89b7c90e1a6e33265ea63c2c54b9..35c3e7551cb1656e7f8c8d298a7d55b74a432e46 100644 (file)
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -1731,7 +1731,13 @@ class SQLCompiler(engine.Compiled):
                         else:
                             self.returning.append(c)
                     else:
-                        if c.default is not None or \
+                        if (
+                                c.default is not None and
+                                (
+                                    not c.default.is_sequence or
+                                    self.dialect.supports_sequences
+                                )
+                            ) or \
                             c is stmt.table._autoincrement_column and (
                                 self.dialect.supports_sequences or
                                 self.dialect.preexecute_autoincrement_sequences

diff --git a/test/sql/test_defaults.py b/test/sql/test_defaults.py
index 79514eaf405beb7f4bc94710719b3dc23c3f0a8b..ae36e8b5a622216e9af5067ab53fec0eac00472f 100644 (file)
--- a/test/sql/test_defaults.py
+++ b/test/sql/test_defaults.py
@@ -603,6 +603,33 @@ class AutoIncrementTest(fixtures.TablesTest):
 
         nonai.insert().execute(id=1, data='row 1')
 
+
+    def test_col_w_sequence_non_autoinc_no_firing(self):
+        metadata = self.metadata
+        # plain autoincrement/PK table in the actual schema
+        Table("x", metadata,
+            Column("set_id", Integer, primary_key=True)
+        )
+        metadata.create_all()
+
+        # for the INSERT use a table with a Sequence
+        # and autoincrement=False.  Using a ForeignKey
+        # would have the same effect
+        dataset_no_autoinc = Table("x", MetaData(),
+            Column("set_id", Integer, Sequence("some_seq"),
+                        primary_key=True, autoincrement=False)
+            )
+
+        testing.db.execute(
+                dataset_no_autoinc.insert()
+        )
+        eq_(
+            testing.db.scalar(dataset_no_autoinc.count()), 1
+        )
+
+
+
+
 class SequenceDDLTest(fixtures.TestBase, testing.AssertsCompiledSQL):
     __dialect__ = 'default'
 
@@ -875,6 +902,7 @@ class SequenceTest(fixtures.TestBase, testing.AssertsCompiledSQL):
         assert not self._has_sequence('s1')
         assert not self._has_sequence('s2')
 
+
 cartitems = sometable = metadata = None
 class TableBoundSequenceTest(fixtures.TestBase):
     __requires__ = ('sequences',)