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.
12. The data converting apparatus according to claim 8 , further comprising an updating unit that updates, in the encoded meta-definition information, the metadata code that is for the conversion source and has been converted by the converting unit, the converted metadata code for the conversion source being updated to the metadata code for the conversion destination before the next execution of the detecting process by the detecting unit.