1. A computer-readable, non-transitory medium storing a data distribution program for causing a computer to execute a process for distributing data table to a plurality of database devices, the process comprising: storing the data table in a storing unit, the data table including a plurality of data item groups, each of the plurality of data item groups including a plurality of pieces of data relating to a same data item of a plurality of records; reading, from the storing unit, exclusivity information about placement of the plurality of data item groups on the plurality of database devices; deciding database devices the plurality of data item groups, respectively, based on the exclusivity information; and transmitting the plurality of data item groups to the plurality of database devices, respectively, according to the-deciding, wherein the exclusivity information indicates that specified two or more data item groups among the plurality of data item groups are not placed in a same database device among the plurality of database devices.