Microsoft® Access® 2010 24-Hour Trainer

16

Creating Table Relationships

Access 2010 is a Relational Database Management System (RDMS), as are all previous versions of Access. The heart of RDMS is the ability to eliminate or limit the need to store redundant data. The method used to eliminate duplicated data requires conforming to the rules of normalization, rules that were originally defined by Edgar F. Codd in 1971. Normalization works because data in one table is related to data in one or more other tables. The relationships can be implicitly created in a SQL statement, or explicitly created and enforced by the RDMS.

Relationships between tables in an Access database can be explicitly created in the Relationship Tools designer on the Database Tools Ribbon. Access relationships can be defined to require referential integrity. Referential integrity is the primary way to require that a parent record exists for each child record and to prevent the deletion of parent records when related child records exist. Deleting the parent record and leaving the related child records results in what are called orphan records, which cause reporting anomalies because the information is not intact. Referential integrity is used to help prevent orphan records within a database system.

LESSON SETUP

In this lesson you learn about the different types of relationships and how to create them in Access 2010. You learn how to use the Access 2010 Relationship Tool to create and modify relationships between tables in an Access database.

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