Secondary index / Secondary indexing / Non-clustering index / Non-clustered index
|Secondary index - example|
Points to know about secondary index:
- Secondary index must be a dense index
- Order of the search key values in the index file and the order of the actual records that are related to the index entries are in different order.
- Secondary Indexes facilitate query-answering on attributes other than primary keys – or, more generally, on non-ordering attributes.
- A file can have several secondary indexes.