What are single-column indexes in databases?

What are single-column indexes in databases?

Single-column indexes are database indexes that are created on a single column of a table. They improve query performance by allowing the database to quickly locate rows based on the values in that column.

How do they differ from multi-column indexes?

Multi-column indexes are created on two or more columns, allowing for more complex queries. Single-column indexes are simpler and faster for queries that filter on just one column.

When should I use a single-column index?

You should use a single-column index when you frequently query a table based on a specific column, especially if that column has a high degree of uniqueness.

Can single-column indexes slow down write operations?

Yes, while they speed up read operations, single-column indexes can slow down write operations because the index needs to be updated whenever data is inserted, updated, or deleted.

What are some best practices for using single-column indexes?

Best practices include indexing columns that are frequently used in WHERE clauses, avoiding indexing columns with low selectivity, and regularly monitoring index performance.