Selections Using Indices Index scan-search algorithms that use an index selection condition must be on search-key of index. A2(primary index,equality on key).Retrieve a single record that satisfies the corresponding equality condition Cost=(hi+1)(t+ts) A3(primary index,equality on nonkey)Retrieve multiple records. Records will be on consecutive blocks Let b number of blocks containing matching records Cost=hi *(tT+ts)+ts+t*b Database System Concepts-6th Edition 12.11 @Silberschatz,Korth and SudarshanDatabase System Concepts - 6 12.11 ©Silberschatz, Korth and Sudarshan th Edition Selections Using Indices Index scan – search algorithms that use an index selection condition must be on search-key of index. A2 (primary index, equality on key). Retrieve a single record that satisfies the corresponding equality condition Cost = (hi + 1) * (tT + tS) A3 (primary index, equality on nonkey) Retrieve multiple records. Records will be on consecutive blocks  Let b = number of blocks containing matching records Cost = hi * (tT + tS ) + tS + tT * b