1. A program stored on a computer-readable medium, which refers to a first data schema and a second data schema that describe data structures to correlate a data item name constituting the first data schema with a data item name constituting the second data schema, the program being implemented on and controlling a computer to execute the procedures of: extracting the data item name constituting the first data schema; extracting the data item name constituting the second data schema; extracting element concepts included in the extracted data item names of the first data schema and the second data schema; setting a distinctive relation and a time-sequential order relation between the data item names based on the extracted element concepts; reading the data item names of the first data schema and the second data schema and setting a correlation between the two read data item names based on the distinctive relation to satisfy a constraint imposed by the time-sequential order relation between the data item names; and accumulating the correlation of the data item names; reading two data item names of one of the first data schema and the second data schema; extracting a set of common character strings from among character strings constituting the two data item names as a first element concept when character strings of the two data item names are compared with each other and are judged to include synonymous character strings; and extracting a set of character strings excluding common character strings from the character strings constituting the two data item names as a second element concept when the character strings of the two data item names are compared with each other and are judged to include synonymous character strings; judging a time-sequential order relation for the two item names corresponding to the second element concept; and setting that the set of character strings constituting the second element concept has a distinctive relation when no time-sequential order relation is included in the second element concept.