Added reflection method :meth:`.Inspector.get_sequence_names`

Added new reflection method :meth:`.Inspector.get_sequence_names` which
returns all the sequences defined. Support for this method has been added
to the backend that support :class:`.Sequence`: PostgreSql, Oracle,
MSSQL and MariaDB >= 10.3.

Fixes: #2056
Change-Id: I0949696a39aa28c849edf2504779241f7443778a

1 files changed, 33 insertions, 32 deletions

diff --git a/lib/sqlalchemy/dialects/postgresql/base.py b/lib/sqlalchemy/dialects/postgresql/base.py
index 441e77a37..2bfb9b494 100644
--- a/lib/sqlalchemy/dialects/postgresql/base.py
+++ b/lib/sqlalchemy/dialects/postgresql/base.py
@@ -2682,39 +2682,23 @@ class PGDialect(default.DefaultDialect):
 
     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 relname=:name"
-                ).bindparams(
-                    sql.bindparam(
-                        "name",
-                        util.text_type(sequence_name),
-                        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 relname=:name"
-                ).bindparams(
-                    sql.bindparam(
-                        "name",
-                        util.text_type(sequence_name),
-                        type_=sqltypes.Unicode,
-                    ),
-                    sql.bindparam(
-                        "schema",
-                        util.text_type(schema),
-                        type_=sqltypes.Unicode,
-                    ),
-                )
+            schema = self.default_schema_name
+        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 relname=:name"
+            ).bindparams(
+                sql.bindparam(
+                    "name",
+                    util.text_type(sequence_name),
+                    type_=sqltypes.Unicode,
+                ),
+                sql.bindparam(
+                    "schema", util.text_type(schema), type_=sqltypes.Unicode,
+                ),
             )
+        )
 
         return bool(cursor.first())
 
@@ -2871,6 +2855,23 @@ class PGDialect(default.DefaultDialect):
         return [name for name, in result]
 
     @reflection.cache
+    def get_sequence_names(self, connection, schema=None, **kw):
+        if not schema:
+            schema = self.default_schema_name
+        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"
+            ).bindparams(
+                sql.bindparam(
+                    "schema", util.text_type(schema), type_=sqltypes.Unicode,
+                ),
+            )
+        )
+        return [row[0] for row in cursor]
+
+    @reflection.cache
     def get_view_definition(self, connection, view_name, schema=None, **kw):
         view_def = connection.scalar(
             sql.text(