We discuss disk allocation methods for Cartesian product files by introducing error correcting codes, and have clarified the performance of the methods by system evaluation models developed by using rate distortion theory. Let us assume q n Cartesian product files with n attributes and q actual values in each attribute, and store q n files into G(≤ q n) disks. For a partial match access request, we represent new disk allocation methods which able to access the disks in parallel as much as possible, where the partial match access request includes an indefinite case (don't care: "*") in some attributes and the * requires to access the files with corresponding to the attribute for the all actual attribute values. In this paper, we propose to apply unequal error protection codes to the case where the probabilities of occurrence of the * in the attributes for a partial match access request are not the same. We show the disk allocation methods have desirable properties as n becomes large.