Data distribution is one of the most important steps in distributed database design. This paper proposes a methodology for distributing database by using a relational schema as an input. A design support system called DBDD (Database Distribution Design) is implemented within the framework of this methodology. The methodology consists of three phases such as (i) schema analysis, (ii) fragmentation, and (iii) allocation. In the schema analysis phase, all the table names are acquired from a global relational schema. In the fragmentation phase, fragments are generated according to transaction retrieval patterns. Furthermore, DBDD enhances the design quality by allocating fragments in a progressive manner. A real-life case is illustrated to demonstrate the practical usefulness of the DBDD.