You can use the capture-schema command to manually generate the database metadata (.dbschema) file. For details, see the Oracle GlassFish Server 3.0.1 Reference Manual.
The capture-schema utility does not modify the schema in any way. Its only purpose is to provide the persistence engine with information about the structure of the database (the schema).
Keep the following in mind when using the capture-schema command:
The name of a .dbschema file must be unique across all deployed modules in a domain.
If more than one schema is accessible for the schema user, more than one table with the same name might be captured if the -schemaname option of capture-schema is not set.
The schema name must be upper case.
Table names in databases are case-sensitive. Make sure that the table name matches the name in the database.
PostgreSQL databases internally convert all names to lower case. Before running the capture-schema command on a PostgreSQL database, make sure table and column names are lower case in the sun-cmp-mappings.xml file.
An Oracle database user running the capture-schema command needs ANALYZE ANY TABLE privileges if that user does not own the schema. These privileges are granted to the user by the database administrator.