Database Reference
In-Depth Information
Figure 10.41. Is there a problem with either of these tables?
You note that there's a many-to-many relationship between the tables and then realize
that your colleague tried to establish this relationship by taking a copy of the P
RODUCT
N
UMBER
and Q
UOTE
P
RICE
fields from the PRODUCTS table and incorporating them into
the ORDERS table. He thought that this was the best way to associate various products
with a particular order. The presence of these fields in the ORDERS table, however, pro-
duces a large amount of redundant data.
Figure 10.42
illustrates this problem quite clearly.
Figure 10.42. Redundant data caused by an improperly established many-to-many
relationship
