Key Points

• When you create a database with Microsoft Office Access 2003, you can set properties that restrict what can be entered in it.

• To ensure the ongoing accuracy of a database, you can create and run action queries that quickly update information or delete selected records from a table.

• The Data Type setting restricts entries to a specific type of data: text, numbers , dates, and so on. For example, if the data type is set to Number and you try to enter text, Access refuses your entry and displays a warning.

• You can set the Field Size property for the Text, Number, and AutoNumber data types. This property restricts the number of characters allowed in a text field, and the size of numbers that can be entered in a number or AutoNumber field.

• The input mask property controls the format in which data can be entered, and restricts the number of characters that can be entered in a field. For example, the mask for a telephone number can be set to have three sections separated by semicolons, so someone entering information can see at a glance the format for ten numbers in that particular field.

• You can use a validation rule to precisely define the information that will be accepted in one or several fields in a record. At the field level, Access uses the rule to test an entry when you attempt to leave the field, and does not accept entries that dont meet the rule. At the table level, Access uses the rule to test the content of several fields when you attempt to leave the record, rejecting an entry that doesnt satisfy the rule.

• For fields in which the number of correct entries is limited, you can use a lookup field to ensure that users enter the right information. This helps prevent inconsistencies in how data is entered and makes it easier and more efficient to sort and perform searches on your data.

• You can use an update query to quickly perform an action based on the results of a query. For example, you can search and replace the contents of a field under certain circumstances, which are defined in the update query.

• You can use a delete query to quickly delete records that have become obsolete. You should always back up your database before running a delete query,and you must exercise caution when deleting records in this way. The effectsof a delete query can be far-reaching, and there is no quick recovery of deleted records.