Merge pull request #58 from FundingCircle/GDP-2765-missing-schema-met…

…adata

Check schema metadata

metadata-ingestion/src/datahub/ingestion/source/tableau.py

@@ -144,6 +144,8 @@
     OwnershipTypeClass,
     SubTypesClass,
     ViewPropertiesClass,
+    SchemaMetadataClass,
+    EditableSchemaMetadataClass
 )
 from datahub.sql_parsing.sql_parsing_result_utils import (
     transform_parsing_result_to_in_tables_schemas,
@@ -2250,7 +2252,13 @@ def emit_table(
             tableau_columns, database_table.parsed_columns
         )
         if schema_metadata is not None:
-            dataset_snapshot.aspects.append(schema_metadata)
+            # Check if table already has schema metadata
+            current_schema_aspect = self.ctx.graph.get_aspect(entity_urn=database_table.urn, aspect_type=SchemaMetadataClass)
+            current_editable_schema_aspect = self.ctx.graph.get_aspect(entity_urn=database_table.urn, aspect_type=EditableSchemaMetadataClass)
+            if current_schema_aspect or current_editable_schema_aspect:
+                logger.debug(f"Table {database_table.urn} already has schema metadata, skipping")
+            else:
+                dataset_snapshot.aspects.append(schema_metadata)
 
         yield self.get_metadata_change_event(dataset_snapshot)