Managing Indexes

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Indexes are optional structures associated with tables. You can create them to improve query performance. Just as the index in this book helps you to quickly locate specific information, an Oracle Database XE index provides a quick access path to table data. Before you add additional indexes, examine the performance of your database. You can then compare performance after the new indexes are added.

You can create indexes on one or more columns of a table. After an index is created, it is automatically maintained and used by Oracle Database XE. Changes to the structure of a table or data in a table, such as adding new rows, updating rows, or deleting rows, are automatically incorporated into all relevant indexes.

This section contains the following topics:

• Index Types

• Indexes for Use with Constraints

• Guidelines for Creating Indexes

• Creating an Index

• Displaying an Index for a Table

• Dropping an Index