To prevent the duplication of information in a database by repeating
fields in more than one table, table relationships can be established
to link fields of tables together. Follow the steps below to set
up a relational database:
- Click the Relationships button on the toolbar.
- From the Show Table window (click the Show Table
button on the toolbar to make it appear), double click on the
names of the tables you would like to include in the relationships.
When you have finished adding tables, click Close.
- To link fields in two different tables, click and drag a field
from one table to the corresponding field on the other table and
release the mouse button. The Edit Relationships window
will appear. From this window, select different fields if necessary
and select an option from Enforce Referential Integrity if necessary.
These options give Access permission to automatically make changes
to referential tables if key records in one of the tales is deleted.
Check the Enforce Referential Integrity box to ensure that
the relationships are valid and that the data is not accidentally
deleted when data is added, edited, or deleted. Click Create
to create the link.
- A line now connects the two fields in the Relationships window.
- The datasheet of a relational table will provide expand and
collapse indicators to view subdatasheets containing matching
information from the other table. In the example below, the student
address database and student grade database were related and the
two can be shown simultaneously using the expand feature. To expand
or collapse all subdatasheets at once, select Format|Subdatasheet|Expand
All or Collapse All from the toolbar.