Key Differences Between Clustered and Non-Clustered Indexes in a Database

In database administration, understanding the differences between clustered and non-clustered indexes is crucial for efficient data retrieval and query optimization. Here are the key differences:

Clustered Index:

• Defines the physical order of data rows in a table.
• Only one clustered index can be created per table.
• Data rows are stored in the leaf nodes of the index B-tree structure.
• Table data is sorted based on the clustered index key.
• Clustered indexes are ideal for columns frequently used in range queries or ordered by.

Non-Clustered Index:

• Does not define the physical order of data rows in a table.
• Multiple non-clustered indexes can be created per table.
• Leaf nodes of the index B-tree structure contain pointers to the actual data rows.
• Table data storage order is not affected by non-clustered indexes.
• Non-clustered indexes are suitable for columns frequently used in search queries.

By understanding and leveraging the differences between clustered and non-clustered indexes, database administrators can optimize query performance and enhance overall database efficiency.