8. The data converting apparatus according to claim 1 , wherein in the encoded meta-definition information, the conversion rule code is assigned as sequential numbers in order of priority of the metadata, and the detecting unit, by referring to the encoded meta-definition information, executes a detecting process of detecting the metadata code for the conversion source and the metadata code for the conversion destination having the conversion rule codes identical at the conversion source and at the conversion destination in descending order of priority.
9. The data converting apparatus according to claim 8 , wherein the metadata is described by an element selected from among a data type of the data to be converted, a type attribute of the data type, and a value of the type attribute, and in the encoded meta-definition information, a priority sequence of the data type and the type attribute are set with respect to the conversion rule code.