Microsoft® Access® 2010 24-Hour Trainer

12

Data Validation and Limiting User Input

A very important part of Access table design is determining how data values can be entered into the database application. Providing methods that permit the user to enter only values that are appropriate for the records in the table is a fundamental problem of storing data in any type of database. Moreover, it is often desirable to have the data being entered formatted consistently throughout the records. For example, consider a phone number field. The format in which values are entered into this field could be very different, especially if multiple users are entering the data. One user might enter the value 3035551234, while another user might enter the value 303-555-1234, and even a third user might enter a value of [phone]. And this doesn't even consider all of the other data entry mistakes that could occur, such as missing or invalid digits in the phone number. The sheer number of problems with data entry can be a bit overwhelming. If no constraints are enforced by the application, users can easily enter incorrect, improper, or non-uniform data values, which can result in inconsistent search results and other unexpected behavior in the application. This lesson is dedicated to discussing the field properties that can be used to validate, limit, and format data values for table records using Access 2010.

LESSON SETUP

In this lesson, you examine the field properties used to ensure the data values for records have been validated. ...