A handler that is invoked with the schema of the source and the
existing schema in the metastore.
This allows a handler to decide how to handle differences. For instance
an implementation may choose to evolve the metastore schema to add missing fields.
Another implemention may throw an exception if the schemas are not aligned.
A handler that is invoked with the schema of the source and the existing schema in the metastore.
This allows a handler to decide how to handle differences. For instance an implementation may choose to evolve the metastore schema to add missing fields. Another implemention may throw an exception if the schemas are not aligned.