Use the Mapping editor to remove existing mappings.
Note: If your input JAR or EAR file contains CMP beans, the EJB deployment
tool looks for an existing schema and map to use when generating deployment
code. If no existing schema and map are found, a schema and map are created
using top-down mapping rules. If you have autobuild enabled and set your server
preferences to automatically publish, then any change to the project will
immediately result in a map being automatically created with the database
name "TopDownDB"