How to delete indexes from oracle

Answer: The steps to delete an index in Oracle include: identifying the index to be deleted; using the DROP INDEX statement to delete the index; and recompiling the affected object.

How to delete an Oracle index

Oracle indexing is a data structure used to improve database query performance. While indexes are often helpful for performance, they are sometimes required to be deleted. This article describes the steps to delete an index in Oracle.

Step 1: Identify the index to be deleted

First, you need to identify the index to be deleted. You can find the index list by querying the DBA_INDEXES view, as shown below:

 <code class="sql">SELECT index_name, table_name, index_type FROM DBA_INDEXES WHERE table_name = 'YOUR_TABLE_NAME';</code>

Step 2: Delete the index

Once the index you want to delete is found, you can delete it using the DROP INDEX statement. The syntax is as follows:

 <code class="sql">DROP INDEX index_name;</code>

Note that index_name is the name of the index to be deleted.

Step 3: Recompile the affected object

After deleting the index, you need to pay attention to recompiling the affected objects. This is to ensure that Oracle understands that the index has been deleted and can optimize the query plan. The affected objects can be recompiled using the following statement:

 <code class="sql">ALTER TABLE table_name COMPILE;</code>

Additional Information

• If the index is part of a unique index or primary key constraint, it cannot be deleted.
• Deleting an index can affect the performance of your database, so it is best to weigh the pros and cons before deleting an index.
• You can use SET TRANSACTION READ ONLY statement to ensure that no concurrent data changes occur after the index is deleted.
• To improve performance, it is recommended to monitor indexes regularly and delete indexes that are no longer needed.

The above is the detailed content of How to delete indexes from oracle. For more information, please follow other related articles on the PHP Chinese website!