Database Reference
In-Depth Information
Figure 10.40
shows how you establish the many-to-many relationship between the
STUDENTSandCLASSEStables.(Notethenewdiagramsymbolusedtorepresentalink-
ing table.)
Figure 10.40. Establishing the many-to-many relationship between the STUDENTS
and CLASSES tables
Note
You could have used STUDENT SCHEDULES or CLASS SCHEDULES as the
name of the linking table; STUDENT CLASSES just happens to be my personal
preference. The point to remember is that you should use a name that makes the
most sense to you or the organization.
Creating a linking table produces a few noteworthy results.
•
The original many-to-many relationship has been dissolved because there is no
longer a direct relationship between the STUDENTS and CLASSES tables.
The
original relationship has been replaced by two one-to-many relationships: one
between STUDENTS and STUDENT CLASSES and another between CLASSES
and STUDENT CLASSES. In the first relationship, a single record in STUDENTS
can be associated with one or more records in STUDENT CLASSES, but a single
record in STUDENT CLASSES table can be associated with only one record in
STUDENTS. In the second relationship, a single record in the CLASSES table can
be associated with one or more records in STUDENT CLASSES, but a single re-
