fix: Adjust find-tables to properly get Oracle and Postgres schemas (…

…#1034)

* Debugging find-tables issue

* Remove debugging printing of schemas and table maps

* fix: Add override method to list schemas for Postgres

data_validation/__main__.py

@@ -368,6 +368,7 @@ def get_table_map(client, allowed_schemas=None):
     """Return dict with searchable keys for table matching."""
     table_map = {}
     table_objs = clients.get_all_tables(client, allowed_schemas=allowed_schemas)
+
     for table_obj in table_objs:
         table_key = ".".join([t for t in table_obj if t])
         table_map[table_key] = {

data_validation/clients.py

@@ -182,7 +182,7 @@ def list_schemas(client):
 
 def list_tables(client, schema_name):
     """Return a list of tables in the DB schema."""
-    if client.name in ["oracle", "postgres", "db2", "mssql", "redshift", "snowflake"]:
+    if client.name in ["db2", "mssql", "redshift", "snowflake"]:
         return client.list_tables()
     return client.list_tables(database=schema_name)
 

third_party/ibis/ibis_postgres/client.py

@@ -58,4 +58,17 @@ def _get_type(typestr: str) -> dt.DataType:
     return _parse_numeric(typestr)
 
 
+def list_schemas(self, like=None):
+    with self.begin() as con:
+        # Databases on Postgres are not the same as schemas and for this method we need the schema list (SQL query reference: https://dba.stackexchange.com/a/127668)
+        schemas = [
+            row.nspname
+            for row in con.exec_driver_sql(
+                "SELECT nspname FROM pg_catalog.pg_namespace WHERE nspname !~ '^pg_' AND nspname <> 'information_schema' ORDER BY 1"
+            ).mappings()
+        ]
+    return self._filter_with_like(schemas, like)
+
+
 PostgresBackend._metadata = _metadata
+PostgresBackend.list_databases = list_schemas