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This chapter is from the book

Defining Table Relationships

AC07S-1.2.1, AC07S-1.2.2 AC07S-4.2.3

You can define table relationships in several ways. After you create tables in your database, you can define table relationships between them. You can define and manage relationships using buttons on the Database Tools tab. This gives you control over your table relationships and also gives you a quick snapshot of all the relationships in your database. After you define a relationship, you can double-click the connection line to modify or add to the relationship.

Define Table Relationships

yellow_circle_1.gif Click the Database Tools tab.

yellow_circle_2.gif Click the Relationships button.

If relationships are already established in your database, they appear in the Relationships window. In this window you can create additional table relationships.

yellow_circle_3.gif If necessary, click the Show Table button to display the Show Table dialog box.

yellow_circle_4.gif Click the Tables tab.

yellow_circle_5.gif Click the table you want.

yellow_circle_6.gif Click Add.

The table or query you selected appears in the Relationships window.

Repeat steps 5 and 6 for each table you want to use in a relationship.

yellow_circle_7.gif Click Close.

yellow_circle_8.gif Drag the common field in the first table to the common field in the second table. When you release the mouse button, a line appears between the two tables, signifying that they are related. Also, the Edit Relationships dialog box opens, in which you can confirm or modify the relationship.

yellow_circle_9.gif Click the Join Type button if you want to specify the join type. Click OK to return to the Edit Relationships dialog box.

yellow_circle_10.gif Click Create to create the relationship.

Join Types

Join Types

Description

Include rows only where the joined fields from both tables are equal

Choose this option if you want to see one record in the second table for every record that appears in the first table. The number of records you see in the two tables will be the same.

Include ALL records from “xxx” (the first table) and only those records from “yyy” (the second table) where the joined fields are equal

Choose this option if you want to see all the records in the first table (even if there is no corresponding record in the second table) as well as the records from the second table in which the joined fields are the same in both tables. The number of records you see in the first table might be greater than the number of records in the second table.

Include ALL records from “yyy” (the second table) and only those records from the “xxx” (the first table) where the joined fields are equal

Choose this option if you want to see all the records in the second table (even if there is no corresponding record in the first table) as well as the records from the first table in which the joined fields are the same in both tables. The number of records you see in the second table might be greater than the number of records in the first table.

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