If I understood correctly, you can design the schema in following way:
columns:
user_id, record_type, name, schemaname, last_modified_date
user_id is your row key (partition key)
record_type or so (e1, e2) might be the cluster key in case e1, e2 are unique within single user. Otherwise your cluster key might be composite including field set for making unique keys
In first case PRIMARY_KEY(user_id, record_type)
e1 e2
123 : {name, schemaname, date } | {name, schemaname, date }
The example for second could be PRIMARY_KEY(user_id, record_type, name)
e1|name e2|name
123 : {schemaname, date } | {schemaname, date }
Does it sounds ok?
Finally I'd say there is a very good official Datastax driver for cassandra native transport: