PURPOSE: To complete the function as a document data file, by setting the plural attribute values for 1 attribute per tapple in the data file using the relation model.

CONSTITUTION: The single value index table 1 is an index table for the attribute with 1 value only per attribute concerning 1 tapple, and multi-value index table 2 is an index table for the attribute with plural values per attribute concerning 1 tapple. For the index table R/W circuit three, the retrieval demand signal, attribute and attribute value are received from the control portion 9, the document number is taken out from the single value index table 1 or multi-value index table 2, are written in the result memory 6, or the write demand signal from the control portion 9, attribute, attribute value and document number are received and they are written in the single value index table 1 or multi-value index table 2. The attribute information memory R/W circuit 4 reads the informaton concerning the attribute for the attribute information memory 5 or writes it.