Description: A non-clustered index is a type of index in databases that enhances query speed without altering the physical order of data in the table. Unlike a clustered index, which organizes data on disk according to the index, a non-clustered index is stored in a separate structure. This means that the table data can remain in its original order while the index provides quick access to rows through pointers that point to the data locations. This type of index is particularly useful in situations where many search queries are performed, as it allows for more efficient information retrieval. Non-clustered indexes can include multiple columns and are ideal for columns that are not primary keys, thus optimizing query performance. Additionally, they can coexist with clustered indexes in the same table, offering flexibility in data management and query optimization. In various database management systems, non-clustered indexes are an essential tool for improving the efficiency of read operations, resulting in faster and more effective overall performance in managing large volumes of data.
