How to properly utilize Oracle indexes?

The basic principles of correctly using Oracle indexes are as follows:

1. Choose the appropriate columns for indexing: Select columns that are frequently used for querying and joining, especially those with high selectivity and frequent access.
2. Avoiding excessive indexing: Having too many indexes will increase the cost of data insertion, updates, and deletions, as well as taking up more storage space. Choose only the most important columns to index to prevent over-indexing.
3. Clustered index: For tables that frequently undergo range queries, consider creating a clustered index. This index stores adjacent data physically together, improving query performance.
4. Consider the order of indexed columns: For multi-column indexes, define them in the order of columns frequently used in queries to improve query performance.
5. Consider using a covering index: If a query only needs to access the indexed columns without requiring access to other columns in the table, creating a covering index can reduce the need to access the table.
6. Regular index maintenance: For tables that are frequently updated, it is advisable to periodically rebuild the index to maintain its performance.
7. Using index hints: In some cases, the optimizer may not select the optimal index, so index hints can be used to specify the index to be used.
8. Monitor index performance by monitoring the usage and performance metrics of indexes, in order to promptly identify and resolve any index performance issues.
9. Management of statistical information: Timely collection and updating of statistics for tables to assist the optimizer in selecting appropriate indexes.

In conclusion, proper use of Oracle indexes requires a comprehensive consideration based on actual situations, balancing the number of indexes with performance needs, and regularly maintaining and optimizing them.