Research on relational algebra and SQL query optimization
Yaping Wang · Electronic Design Engineering · 2009
In this paper,the query cost before and after the equivalent transformation of the relational algebra expression is researched and analyzed in detail.Aiming at how the DBMS query optimizer to generate the smallest cost query plan,optimization rules of the relational algebra expression are given.SQL query optimization strategy based on equivalent transformation rules of the relational algebra is proposed.The strategy provides the design basis for the query optimizer to generate query plan of the smallest cost.