PURPOSE: To simply add and delete the data by providing a pointer which shows an attribute value or plural attribute value records as the value of an attribute value field of a relational table.

CONSTITUTION: A pointer P is provided to show an attribute value or plural attribute value records as the value of an attribute value field of a relational table α. Thus a relational data base device is obtained and applies an attribute value and the pointer with switching according to a fact whether 2 corresponding attribute values are available or not. In other words, the pointer P can point the attribute value records β and γ in the attribute value field of the table α. As a result, the non-regulated data is easily processed and at the same time the number of necessary storage areas is decreased.