![]() ![]() Otherwise, the overhead of updating the index slows down the insert or load operation. Typically, you insert or load data into a table (using SQL*Loader or Import) before creating indexes. Oracle9i Database Performance Guide and Reference for information on query hints and measuring the performance benefits of indexes.Ĭreate Indexes After Inserting Table Data ![]() ![]() Some simple guidelines to follow when managing indexes are included. The following sections explain how to create, alter, and drop indexes using SQL commands. Sometimes, if an index is not being used by default, you can use a query hint so that the index is used. You should use the EXPLAIN PLAN feature to determine how the indexes are being used in your queries. Otherwise, they just take up space and add overhead when the indexed columns are updated. Indexes provide faster access to data for operations that return a small portion of a table's rows.Īlthough Oracle allows an unlimited number of indexes on a table, the indexes only help if they are used to speed up queries. Indexes are used in Oracle to provide quick access to rows in a table. Guidelines for Application-Specific Indexes Oracle9i SQL Reference for the syntax of commands to work with indexes.Oracle9i Database Administrator's Guide for information about creating and managing indexes.Oracle9i Database Performance Guide and Reference for detailed information about using indexes. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |