- Corrected the "has_sequence" query to take current schema,

or explicit sequence-stated schema, into account.
[ticket:1576]

1 files changed, 17 insertions, 7 deletions

diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py
index 0bc5f08b0..061c3b066 100644
--- a/lib/sqlalchemy/dialects/postgresql/base.py
+++ b/lib/sqlalchemy/dialects/postgresql/base.py
@@ -539,13 +539,23 @@ class PGDialect(default.DefaultDialect):
             )
         return bool(cursor.first())
 
-    def has_sequence(self, connection, sequence_name):
-        cursor = connection.execute(
-                    sql.text("SELECT relname FROM pg_class WHERE relkind = 'S' AND "
-                        "relnamespace IN ( SELECT oid FROM pg_namespace WHERE nspname NOT LIKE 'pg_%' "
-                        "AND nspname != 'information_schema' AND relname = :seqname)", 
-                        bindparams=[sql.bindparam('seqname', unicode(sequence_name), type_=sqltypes.Unicode)]
-                    ))
+    def has_sequence(self, connection, sequence_name, schema=None):
+        if schema is None:
+            cursor = connection.execute(
+                        sql.text("SELECT relname FROM pg_class c join pg_namespace n on "
+                            "n.oid=c.relnamespace where relkind='S' and n.nspname=current_schema() and lower(relname)=:name",
+                            bindparams=[sql.bindparam('name', unicode(sequence_name.lower()), type_=sqltypes.Unicode)] 
+                        )
+                    )
+        else:
+            cursor = connection.execute(
+                        sql.text("SELECT relname FROM pg_class c join pg_namespace n on "
+                            "n.oid=c.relnamespace where relkind='S' and n.nspname=:schema and lower(relname)=:name",
+                            bindparams=[sql.bindparam('name', unicode(sequence_name.lower()), type_=sqltypes.Unicode),
+                                sql.bindparam('schema', unicode(schema), type_=sqltypes.Unicode)] 
+                        )
+                    )
+
         return bool(cursor.first())
 
     def table_names(self, connection, schema):