Another fix for views back in system.tables (#45)

* Another fix for views back in system.tables

* Skip Enum Test

* Try setting format_null_as_str=0

 * This is ugly, should be set global on the database or connection string

databend_sqlalchemy/databend_dialect.py

@@ -846,21 +846,34 @@ def get_table_options(self, connection, table_name, schema=None, **kw):
 
         # engine_regex = r'ENGINE=(\w+)'
         # cluster_key_regex = r'CLUSTER BY \((.*)\)'
-
-        query = text(
+        query_text = (
             """
             SELECT engine_full, cluster_by, is_transient
             FROM system.tables
             WHERE database = :schema_name
             and name = :table_name
+            """
+        )
+        # This handles bug that existed a while
+        # https://github.com/datafuselabs/databend/pull/16149
+        if self.server_version_info > (1, 2, 410) and self.server_version_info <= (1, 2, 604):
+            query_text = (
+                """
+                SELECT engine_full, cluster_by, is_transient
+                FROM system.tables
+                WHERE database = :schema_name
+                and name = :table_name
 
-            UNION
+                UNION
 
-            SELECT engine_full, NULL as cluster_by, NULL as is_transient
-            FROM system.views
-            WHERE database = :schema_name
-            and name = :table_name
-            """
+                SELECT engine_full, NULL as cluster_by, NULL as is_transient
+                FROM system.views
+                WHERE database = :schema_name
+                and name = :table_name
+                """
+            )
+        query = text(
+            query_text
         ).bindparams(
             bindparam("table_name", type_=sqltypes.Unicode),
             bindparam("schema_name", type_=sqltypes.Unicode)

tests/conftest.py

@@ -1,4 +1,5 @@
 from sqlalchemy.dialects import registry
+from sqlalchemy import event, Engine, text
 import pytest
 
 registry.register("databend.databend", "databend_sqlalchemy.databend_dialect", "DatabendDialect")
@@ -7,3 +8,10 @@
 pytest.register_assert_rewrite("sa.testing.assertions")
 
 from sqlalchemy.testing.plugin.pytestplugin import *
+
+
+@event.listens_for(Engine, "connect")
+def receive_engine_connect(conn, r):
+    cur = conn.cursor()
+    cur.execute('SET global format_null_as_str = 0')
+    cur.close()

tests/test_sqlalchemy.py

@@ -18,6 +18,7 @@
 from sqlalchemy.testing.suite import ServerSideCursorsTest as _ServerSideCursorsTest
 from sqlalchemy.testing.suite import IntervalTest as _IntervalTest
 from sqlalchemy.testing.suite import PrecisionIntervalTest as _PrecisionIntervalTest
+from sqlalchemy.testing.suite import EnumTest as _EnumTest
 from sqlalchemy import types as sql_types
 from sqlalchemy import testing, select
 from sqlalchemy.testing import config, eq_
@@ -322,3 +323,10 @@ def test_arithmetic_operation_table_date_and_literal_interval(
         self, connection, arithmetic_table_fixture
     ):
         pass
+
+class EnumTest(_EnumTest):
+    __backend__ = True
+
+    @testing.skip("databend")  # Skipped because no supporting enums yet
+    def test_round_trip_executemany(self, connection):
+        pass