Ordered Indices In an ordered index,index entries are stored sorted on the search key value.E.g.,author catalog in library. Primary index:in a sequentially ordered file,the index whose search key specifies the sequential order of the file. Also called clustering index The search key of a primary index is usually but not necessarily the primary key. Secondary index:an index whose search key specifies an order different from the sequential order of the file.Also called non-clustering index. Index-sequential file:ordered sequential file with a primary index. Database System Concepts-6th Edition 11.5 @Silberschatz,Korth and SudarshanDatabase System Concepts - 6 11.5 ©Silberschatz, Korth and Sudarshan th Edition Ordered Indices In an ordered index, index entries are stored sorted on the search key value. E.g., author catalog in library. Primary index: in a sequentially ordered file, the index whose search key specifies the sequential order of the file. Also called clustering index The search key of a primary index is usually but not necessarily the primary key. Secondary index: an index whose search key specifies an order different from the sequential order of the file. Also called non-clustering index. Index-sequential file: ordered sequential file with a primary index