21. Other types of constraints ( unique, primary key, and foreign key constraints ) are not inherited. 22. A table may have multiple foreign keys , and each foreign key can have a different parent table. 23. A table may have multiple foreign keys, and each foreign key can have a different parent table. 24. In particular, the natural join allows the combination of relations that are associated by a foreign key . 25. Is this extension, or inheritance, or neither ?-does the arrow imply a foreign key ? 26. Typically, foreign key relationships will be exposed as an object instance of the appropriate type via a property. 27. At the same time, proper use of foreign keys can minimize data redundancy and chance of destructive anomalies. 28. You can set it up as a foreign key relationship if you decide to use indexes ( recommended ). 29. Finally, overlapping value sets possibly representing foreign key relationships between entities can be explored in an inter-table analysis. 30. The ISDN would be the primary key in the Book table and also a foreign key column in the BookCopy table.
