Article ID: 304272 - View products that this article applies to.
This article was previously published under Q304272
Novice: Requires knowledge of the user interface on single-user computers.
This article applies only to a Microsoft Access database (.mdb).
For a Microsoft Access 2002 version of this article, see 304266
An index helps Microsoft Access find and sort records faster. Access uses indexes in a table the same way that you would use an index in a book. To find data, Access looks up the location of the data in the index.
You can create indexes based on a single field or based on multiple fields. Multiple-field indexes enable you to distinguish between records that may have the same value in the first field.
Deciding Which Fields to IndexFields that you should consider indexing are fields that you search frequently, fields that you sort, or fields that you join to fields in other tables.
The primary key of a table is automatically indexed, and you cannot index a field whose data type is OLE Object. For other fields, you should consider indexing a field if all the following apply:
Creating a Single-Field IndexTo create a single-field index, follow these steps:
Creating Multiple-Field IndexIf you will often search or sort by two or more fields at a time, you can create an index for that combination of fields. For example, if you often set criteria for LastName and FirstName fields in the same query, you should create a multiple-field index on both fields.
When you sort a table by a multiple-field index, Microsoft Access sorts first by the first field that is defined for the index. If there are records with duplicate values in the first field, Microsoft Access sorts next by the second field defined for the index, and so on.
You can include up to 10 fields in a multiple-field index.
To create a multiple-field index, follow these steps: