I am trying to import my data from relational to neo4j. at first as i have a huge amount of table in my database it was giving me the error:NullPointerException: Cannot invoke "org.neo4j.etl.sql.metadata.Column.alias()" because "this.relStartColumn" is null. but when i use the cli command with exclude mode i am able to get the mapping file. now can you tell me how can i put that externally mapped file into etl tool gui? or how to use that to import sql data to neo4j?