23. The data converting method according to claim 22 , comprising: acquiring specification definition information that defines the metadata for a conversion source and defines the data converting function; setting a metadata encoding table that correlates with the metadata for the conversion source, a metadata code specifying the metadata that is for the conversion source and is in the specification definition information acquired at the acquiring; setting the conversion rule table; and constructing the conversion rule.
22. A data converting method executed by a computer having access to a storage unit, the method comprising: storing in the storage unit encoded meta-definition information that assigns a unique conversion rule code to a metadata code that specifies metadata for a conversion source and for a conversion destination and is in meta-definition information defining the metadata for the conversion source and for the conversion destination, a data converting function that converts conversion source data, which has a property prescribed by the metadata for the conversion source, to have a property prescribed by the metadata for the conversion destination, a conversion rule table that assigns the data converting function, according to a combination of a metadata code for the conversion source and a metadata code for the conversion destination, and a conversion rule that correlates with each of the conversion rule tables, a relevant metadata code as a conversion rule code; receiving input of data to be converted; detecting the metadata codes of the conversion source and the conversion destination for which the conversion rule code matches between the conversion source and the conversion destination, by referring to the encoded meta-definition information stored in the storage unit; determining whether the detected metadata codes for the conversion source and the conversion destination match; specifying the data converting function, according to the combination of the metadata code for the conversion source and the metadata code for the conversion destination, by referring to a conversion rule stored in the storage unit and based on the determination result obtained at the determining; and converting the conversion source data, which is the data to be converted, to have a property prescribed by metadata for the conversion destination, by using the data converting function specified at the specifying.