3. A program design supporting apparatus according to claim 1, further comprising a repository for storing and managing the interface information and data items, said interface definition means reading the interface information and a data item from said repository so that they are used for the interface definition.
3. A program design supporting apparatus according to claim 1, further comprising a repository for storing and managing the interface information and data items, said interface definition means reading the interface information and a data item from said repository so that they are used for the interface definition. 5. A program design supporting apparatus according to claim 3, wherein said program definition means, said inter-program relation definition means and said interface definition means register the defined information into said repository, and a plurality of said program definition means, a plurality of said inter-program relation definition means and a plurality of said interface definition means make access to said repository.