4. A system for database indexing of a database, a database index comprises at least one index include, the system comprising: a computer system comprising one or more computer processors, one or more computer-readable storage media, and program instructions stored on one or more of the computer-readable storage media for execution by at least one of the one or more processors, the computer system comprising: an obtaining unit configured to obtain a number of executions, the number of executions of each of a plurality of Structured Query Language (SQL) statements within a certain time period for the database, respectively, wherein the plurality of SQL statements use the database index; a hit frequency calculating unit configured to, for the at least one index: calculate a number of hits of the index include according to the number of executions of each of the plurality of SQL statements; obtain a length of the index include; calculate a hit frequency of the index include by using the number of hits and the length of the index include, wherein: the hit frequency equals the number of hits divided by the length; reserving the index include, using a reserving unit configured to reserve the index include, according to a predetermined criterion, and wherein the reserving unit is further configured to reserve the index include according to the predetermined criterion comprises reserving the index include whose hit frequency is greater than a predetermined threshold; introducing into the database index, the reserved index include whose hit frequency is greater than the predetermined threshold; and performing an index re-org, using a re-org unit configured to perform the index re-org, by using the reserved index include such that the reserve index include whose hit frequency is greater than the predetermined threshold is being introduced in the database index, resulting in improved query performance of the database index for optimizing database indexing, and thereby not requiring designation of index includes by a database administrator.
4. A system for database indexing of a database, a database index comprises at least one index include, the system comprising: a computer system comprising one or more computer processors, one or more computer-readable storage media, and program instructions stored on one or more of the computer-readable storage media for execution by at least one of the one or more processors, the computer system comprising: an obtaining unit configured to obtain a number of executions, the number of executions of each of a plurality of Structured Query Language (SQL) statements within a certain time period for the database, respectively, wherein the plurality of SQL statements use the database index; a hit frequency calculating unit configured to, for the at least one index: calculate a number of hits of the index include according to the number of executions of each of the plurality of SQL statements; obtain a length of the index include; calculate a hit frequency of the index include by using the number of hits and the length of the index include, wherein: the hit frequency equals the number of hits divided by the length; reserving the index include, using a reserving unit configured to reserve the index include, according to a predetermined criterion, and wherein the reserving unit is further configured to reserve the index include according to the predetermined criterion comprises reserving the index include whose hit frequency is greater than a predetermined threshold; introducing into the database index, the reserved index include whose hit frequency is greater than the predetermined threshold; and performing an index re-org, using a re-org unit configured to perform the index re-org, by using the reserved index include such that the reserve index include whose hit frequency is greater than the predetermined threshold is being introduced in the database index, resulting in improved query performance of the database index for optimizing database indexing, and thereby not requiring designation of index includes by a database administrator. 6. The system according to claim 4 , wherein the reserving unit is further configured to: arrange the at least one index include in an ascending order according to the hit frequency; and reserve a predetermined number of index includes with a higher hit frequency.