DATABASE SYSTEMS, METHODS AND COMPUTER PROGRAM PRODUCTS USING TYPE BASED SELECTIVE FOREIGN KEY ASSOCIATION TO REPRESENT MULTIPLE BUT EXCLUSIVE RELATIONSHIPS IN RELATIONAL DATABASES

摘要

Database systems, methods and/or computer program products provide for multiple but exclusive relationships between tables in a relational database. The multiple but exclusive relationship may be enforced based on a type associated with a record in a relating table. The multiple but exclusive relationship may be a one-to-many or a many-to-many relationship. A foreign key value of a record in a relating table may be selectively associated with a specific one of a plurality of related tables based on at least one attribute of the record containing the foreign key in the relating table. In particular embodiments of the present invention, the foreign key values of a record in the relating table are selectively associated with one of the plurality of related tables by defining a foreign key of records of the relating table and defining a plurality of types of foreign key associations, each of the types corresponding to a respective one of the plurality of related tables. One of the related tables having a type corresponding to a type value associated with a record of the relating table is selected and a record in the selected related table identified based on a foreign key value of the foreign key of the record in the relating table.