14. The data converting apparatus according to claim 1 , comprising: a specification-definition information acquiring unit that acquires specification definition information that defines a specification related to the metadata and defines the data converting function; a first setting unit that sets a metadata encoding table that correlates with the metadata, a metadata code specifying the metadata in the specification definition information acquired by the specification-definition information acquiring unit; a second setting unit that sets the conversion rule table; and a constructing unit that constructs the conversion rule.
14. The data converting apparatus according to claim 1 , comprising: a specification-definition information acquiring unit that acquires specification definition information that defines a specification related to the metadata and defines the data converting function; a first setting unit that sets a metadata encoding table that correlates with the metadata, a metadata code specifying the metadata in the specification definition information acquired by the specification-definition information acquiring unit; a second setting unit that sets the conversion rule table; and a constructing unit that constructs the conversion rule. 19. The data converting apparatus according to claim 14 , further comprising: a meta-definition information acquiring unit that acquires meta-definition information that defines metadata for the conversion source and for the conversion destination; and a generating unit that, for each of the metadata in the meta-definition information acquired by the meta-definition information acquiring unit, generates the encoded meta-definition information by assigning and encoding a conversion rule code specific to the conversion rule table related to the metadata.