A database management method generates an execution plan with respect to a factorized character string generated by factoring an execution value list of a query and storing the factorized character string and an execution plan identifier associated with the factorized character string. The method includes receiving a factorized character string generated from a query; determining whether the factorized character string is stored in a memory; transmitting an execution plan identifier matching the factorized character string stored in the memory when the factorized character string is stored in the memory; generating and transmitting an execution plan identifier with respect to an execution plan of the factorized character string when the factorized character string is not stored in the memory; receiving a query request consisting of the execution plan identifier and an execution value list included in the query; and providing a query result obtained using the query request.