connect 'jdbc:derby:your_database_name;create=true;'; (connects to and optionally creates the specified database name)

show tables; (shows all tables)

describe table_name; (shows column definitions for a specified table)

run 'path_to_script_file'; (runs a script file)

exit; (exits ij)

common commands for connecting and using derby through ij.

ij and derby database

Java