When you sort a table by a multiple-field index, Microsoft Access sorts first by the first field defined for the index. Same query, it makes sense to create a multiple-field index on both fields. Or more fields at a time, you can create an index for that combination of fields.įor example, if you often set criteria for LastName and FirstName fields in the
Multiple-field indexes If you think you'll often search or sort by two Svalues in the field are the same, the index may not significantly speed up queries. You anticipate storing many different values in the field. You anticipate sorting values in the field.ĭ. You anticipate searching for values stored in the field.Ĭ. The field's data type is Text, Number, Currency, or Date/Time.ī. For other fields, you should consider indexing a fieldĪ. The primary key of a table is automatically indexed, and you can't index a field whose data type is OLE Object. However, indexes can slow down some action queries such as append queries, when the indexes for many fields need to be updated while performing these Multiple-field indexes enable you to distinguish between records in which the first field may have the same value.ĭeciding which fields to index You'll probably want to index fields you search frequently, fields you sort, or fields that you join to fields in other tables in Indexes based on a single field or on multiple fields. Microsoft Access uses indexes in a table as you use an index in a book: to find data, it looks up the location of the data in the index. An index helps Microsoft Access find and sort