I am trying to implement M:N relationship with 2 beans CourseBean and StudentBean. The corresponding tables are course, student and enrol. enrol is the join table with two columns each being FK to the PK in course and student tables. When running ejbc on the jar file, I get this error I've copied below: PS: The columns in enrol are studentID and CallNumber. The code for beans and descriptors follow the error message below. I appreciate any help. I've spent a day trying to figure it. Thanks a ton in advance. ~ ERROR: Error from ejbc: Error while reading 'META-INF/weblogic-cmp-rdbms-jar.xml'. The error was: In relationship 'student-courses', role 'students-take-many-courses', invalid column 'sID', a column-map element contains an invalid key-column. The key-column is not defined in the related bean or it's not recognized because of case mismatch. In relationship 'student-courses', role 'courses-have-many-students', invalid column 'courseCallNumber', a column-map element contains an invalid key-column. The key-column is not defined in the related bean or it's not recognized because of case mismatch.