final classDefaultSource extends ExternalSchemaRelationProvider with SchemaRelationProvider with CreatableRelationProvider with DataSourceRegister with Logging
Column tables don't support any extensions over regular Spark schema syntax,
but the support for ExternalSchemaRelationProvider has been added as a workaround
to allow for specifying schema in a CREATE TABLE AS SELECT statement.
Normally Spark does not allow specifying schema in a CTAS statement for DataSources
(except its special "hive" provider), so schema is passed here as string
which is parsed locally in the CreatableRelationProvider implementation.
Linear Supertypes
Logging, DataSourceRegister, CreatableRelationProvider, SchemaRelationProvider, ExternalSchemaRelationProvider, RelationProvider, AnyRef, Any
Column tables don't support any extensions over regular Spark schema syntax, but the support for ExternalSchemaRelationProvider has been added as a workaround to allow for specifying schema in a CREATE TABLE AS SELECT statement.
Normally Spark does not allow specifying schema in a CTAS statement for DataSources (except its special "hive" provider), so schema is passed here as string which is parsed locally in the CreatableRelationProvider implementation.