Database Reference
In-Depth Information
Figure 10.36. The existing one-to-many relationship between the BUILDINGS and
ROOMS tables
The relationship between these two tables is such that a single building can contain one
or more rooms, but a single room is contained within only one building. Using the pro-
cedure outlined earlier, you establish this relationship by taking a copy of the primary key
(B
UILDING
N
UMBER
)fromtheBUILDINGStableandincorporatingitasaforeignkeywith-
in the ROOMS table. Now, revise the relationship diagram and make the same type of ad-
justments as you did with the diagram for the one-to-one relationship. Your revised dia-
gram should look like the one in
Figure 10.37
. (Note that the
middle
line of the crow's foot
symbol is the significant connection point—it should point directly to the foreign key.)
Figure 10.37. Establishing the one-to-many relationship between the BUILDINGS
and ROOMS tables
Resolving Multivalued Fields—Revisited
Backin
Chapter7
youlearnedhowtoresolveamultivaluedfieldbyusingthisgenericpro-
cedure:
