Query optimization gives the good performance of the system and manages heavy workload on the database when transmission on data occurs and the effective usage of database engine and lesser memory consumed. For better performance we need to use best, faster and well-ordered queries. Since we need SQL query tuning based on the customer requirements. Firstly the data in database is optimized and then query. In this paper we propose database watermarking technique which is an effective method for database security. To improve query response time is to reduce the number of disk Inputs/Outputs by partitioning the database vertically and/or horizontally which we achieve using clustering. We present a technique for structured database decomposition based on the relational data
