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Chapter 3. Managing the Consistency, For... > Indexed Property - Pg. 88

Managing the Consistency, Format, and Integrity of Your Data 5. 6. 88 Close the table. You'll see a message box indicating that the AmountSpent field cannot contain a Null value because the Required property is set to True (or Yes). Click OK in the message box, and then click Yes when you're prompted to close the table without saving the record. Indexed Property Indexes help bring order to a mass of data. Most importantly, indexes help you find information that you need quickly. Indexes, which are a part of most databases, are used to lessen the time it takes to locate, sort, and filter records. Access sets the Indexed property for the primary key in a table to Yes (No Duplicates Allowed). You can also set the Indexed property to Yes (Duplicates OK) when you want to create an index for a field that's not a primary key. If most or all of the following guidelines apply to a field, you should create an index for the field: · The data type for the field is Text, Number, Currency, or Date/Time. (You can't index a field whose data type is an OLE Object.) · You expect to use the field's values when searching for records. · You expect to use the field as the basis for sorting records. · The field will contain many different values. Don't index everywhere Indexes can slow down some action queries (such as those that append records to a table) when the indexes for many fields need to be updated while performing these operations.