diff --git a/neutron/db/migration/__init__.py b/neutron/db/migration/__init__.py
index 4151770e8..6b367233b 100644
--- a/neutron/db/migration/__init__.py
+++ b/neutron/db/migration/__init__.py
@@ -14,6 +14,9 @@
 #
 # @author: Mark McClain, DreamHost
 
+from alembic import op
+import sqlalchemy as sa
+
 OVS_PLUGIN = ('neutron.plugins.openvswitch.ovs_neutron_plugin'
               '.OVSNeutronPluginV2')
 CISCO_PLUGIN = 'neutron.plugins.cisco.network_plugin.PluginV2'
@@ -27,3 +30,24 @@ def should_run(active_plugins, migrate_plugins):
                 OVS_PLUGIN in migrate_plugins):
             migrate_plugins.append(CISCO_PLUGIN)
         return set(active_plugins) & set(migrate_plugins)
+
+
+def alter_enum(table, column, enum_type, nullable):
+    bind = op.get_bind()
+    engine = bind.engine
+    if engine.name == 'postgresql':
+        values = {'table': table,
+                  'column': column,
+                  'name': enum_type.name}
+        op.execute("ALTER TYPE %(name)s RENAME TO old_%(name)s" % values)
+        enum_type.create(bind, checkfirst=False)
+        op.execute("ALTER TABLE %(table)s RENAME COLUMN %(column)s TO "
+                   "old_%(column)s" % values)
+        op.add_column(table, sa.Column(column, enum_type, nullable=nullable))
+        op.execute("UPDATE %(table)s SET %(column)s = "
+                   "old_%(column)s::text::%(name)s" % values)
+        op.execute("ALTER TABLE %(table)s DROP COLUMN old_%(column)s" % values)
+        op.execute("DROP TYPE old_%(name)s" % values)
+    else:
+        op.alter_column(table, column, type_=enum_type,
+                        existing_nullable=nullable)
diff --git a/neutron/db/migration/alembic_migrations/versions/1341ed32cc1e_nvp_netbinding_update.py b/neutron/db/migration/alembic_migrations/versions/1341ed32cc1e_nvp_netbinding_update.py
index 43e1dd328..677d6f291 100644
--- a/neutron/db/migration/alembic_migrations/versions/1341ed32cc1e_nvp_netbinding_update.py
+++ b/neutron/db/migration/alembic_migrations/versions/1341ed32cc1e_nvp_netbinding_update.py
@@ -42,6 +42,11 @@ import sqlalchemy as sa
 
 from neutron.db import migration
 
+new_type = sa.Enum('flat', 'vlan', 'stt', 'gre', 'l3_ext',
+                   name='nvp_network_bindings_binding_type')
+old_type = sa.Enum('flat', 'vlan', 'stt', 'gre',
+                   name='nvp_network_bindings_binding_type')
+
 
 def upgrade(active_plugins=None, options=None):
     if not migration.should_run(active_plugins, migration_for_plugins):
@@ -50,10 +55,8 @@ def upgrade(active_plugins=None, options=None):
                     name='phy_uuid',
                     existing_type=sa.String(36),
                     existing_nullable=True)
-    op.alter_column('nvp_network_bindings', 'binding_type',
-                    type_=sa.Enum('flat', 'vlan', 'stt', 'gre', 'l3_ext',
-                                  name='nvp_network_bindings_binding_type'),
-                    existing_nullable=True)
+    migration.alter_enum('nvp_network_bindings', 'binding_type', new_type,
+                         nullable=False)
 
 
 def downgrade(active_plugins=None, options=None):
@@ -63,7 +66,5 @@ def downgrade(active_plugins=None, options=None):
                     name='tz_uuid',
                     existing_type=sa.String(36),
                     existing_nullable=True)
-    op.alter_column('nvp_network_bindings', 'binding_type',
-                    type_=sa.Enum('flat', 'vlan', 'stt', 'gre',
-                                  name='nvp_network_bindings_binding_type'),
-                    existing_nullable=True)
+    migration.alter_enum('nvp_network_bindings', 'binding_type', old_type,
+                         nullable=False)
diff --git a/neutron/db/migration/alembic_migrations/versions/38fc1f6789f8_cisco_n1kv_overlay.py b/neutron/db/migration/alembic_migrations/versions/38fc1f6789f8_cisco_n1kv_overlay.py
index c13ebeaf2..8d1178ce0 100644
--- a/neutron/db/migration/alembic_migrations/versions/38fc1f6789f8_cisco_n1kv_overlay.py
+++ b/neutron/db/migration/alembic_migrations/versions/38fc1f6789f8_cisco_n1kv_overlay.py
@@ -30,27 +30,28 @@ migration_for_plugins = [
     'neutron.plugins.cisco.network_plugin.PluginV2'
 ]
 
-from alembic import op
 import sqlalchemy as sa
 
 from neutron.db import migration
 
 
+new_type = sa.Enum('vlan', 'overlay', 'trunk', 'multi-segment',
+                   name='vlan_type')
+old_type = sa.Enum('vlan', 'vxlan', 'trunk', 'multi-segment',
+                   name='vlan_type')
+
+
 def upgrade(active_plugins=None, options=None):
     if not migration.should_run(active_plugins, migration_for_plugins):
         return
 
-    op.alter_column('cisco_network_profiles', 'segment_type',
-                    existing_type=sa.Enum('vlan', 'overlay', 'trunk',
-                                          'multi-segment'),
-                    existing_nullable=False)
+    migration.alter_enum('cisco_network_profiles', 'segment_type', new_type,
+                         nullable=False)
 
 
 def downgrade(active_plugins=None, options=None):
     if not migration.should_run(active_plugins, migration_for_plugins):
         return
 
-    op.alter_column('cisco_network_profiles', 'segment_type',
-                    existing_type=sa.Enum('vlan', 'vxlan', 'trunk',
-                                          'multi-segment'),
-                    existing_nullable=False)
+    migration.alter_enum('cisco_network_profiles', 'segment_type', old_type,
+                         nullable=False)
diff --git a/neutron/db/migration/alembic_migrations/versions/46a0efbd8f0_cisco_n1kv_multisegm.py b/neutron/db/migration/alembic_migrations/versions/46a0efbd8f0_cisco_n1kv_multisegm.py
index 317dca35e..1c55ce7f2 100644
--- a/neutron/db/migration/alembic_migrations/versions/46a0efbd8f0_cisco_n1kv_multisegm.py
+++ b/neutron/db/migration/alembic_migrations/versions/46a0efbd8f0_cisco_n1kv_multisegm.py
@@ -35,6 +35,9 @@ import sqlalchemy as sa
 
 from neutron.db import migration
 
+new_type = sa.Enum('vlan', 'vxlan', 'trunk', 'multi-segment', name='vlan_type')
+old_type = sa.Enum('vlan', 'vxlan', name='vlan_type')
+
 
 def upgrade(active_plugins=None, options=None):
     if not migration.should_run(active_plugins, migration_for_plugins):
@@ -60,10 +63,8 @@ def upgrade(active_plugins=None, options=None):
         sa.PrimaryKeyConstraint('multi_segment_id', 'segment1_id',
                                 'segment2_id')
     )
-    op.alter_column('cisco_network_profiles', 'segment_type',
-                    existing_type=sa.Enum('vlan', 'vxlan', 'trunk',
-                                          'multi-segment'),
-                    existing_nullable=False)
+    migration.alter_enum('cisco_network_profiles', 'segment_type', new_type,
+                         nullable=False)
     op.add_column('cisco_network_profiles',
                   sa.Column('sub_type', sa.String(length=255), nullable=True))
 
@@ -74,7 +75,6 @@ def downgrade(active_plugins=None, options=None):
 
     op.drop_table('cisco_n1kv_trunk_segments')
     op.drop_table('cisco_n1kv_multi_segments')
-    op.alter_column('cisco_network_profiles', 'segment_type',
-                    existing_type=sa.Enum('vlan', 'vxlan'),
-                    existing_nullable=False)
+    migration.alter_enum('cisco_network_profiles', 'segment_type', old_type,
+                         nullable=False)
     op.drop_column('cisco_network_profiles', 'sub_type')