Partially keyed queries

A partially keyed query is a query where some of the referenced fields are defined in the key that processes the query. Using the index, the query engine can only partially determine whether a record matches the query. For an efficient partially keyed query, the first field in the key must be included in the query expression. If it is not included, all index entries in the index must first be read to determine the results of the query.

Related topics

Nonkeyed queries
Stored queries
True queries
Create a query using more than one field
Tuning: Fully keyed queries
Tuning: Improving query speed