web server - Borland Technical Publications

Container-Managed Persistence in Borland Enterprise Server
CASE 3: a many-tomany
relationship.
We're not quite done with our relationship, though. Now, we need to complete it by
specifying the relationship role for the other direction:
Customer
customers
ORDER
CUSTOMER_NO
CUSTOMER
CUSTOMER_NO
.
.
If you define a many-to-many relationship, you must also have the CMP engine create
a cross-table which models a relationship between the left table and the right table. Do
this using the element, whose XML is:
You may name this cross-table whatever you like using the element. The
two elements correspond to columns in the left and right tables whose
relationship you wish to model. For example, consider two tables, EMPLOYEE and
PROJECT, which have a many-to-many relationship. An employee can be a part of
multiple projects, and projects have multiple employees. The EMPLOYEE table has three
elements, an employee number (EMP_NO), a last name (LAST_NAME), and a project ID
number (PROJ_ID). The PROJECT table contains columns for the project ID number
(PROJ_ID), the project name (PROJ_NAME), and assigned employees by number (EMP_NO).
138 BES Developer’s Guide