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Database Design

1. How are recursive relationships handled?

2. Discuss surrogate keys.

3. Describe the six default referential integrity actions.

4. How are N:M relationships implemented?

5. Why are null values ambiguous?

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1. How are recursive relationships handled?

A recursive relationship is a relationship among entities of the same class, and is represented in the same way as other relationships are. The rows of the tables can take two different roles, however. Some are parent rows, and others are child rows. If a key is supposed to be a parent key and if the row has no parent, its value will be null. If a key is supposed to be a child key and the row has no child, its value will be null.

2. Discuss surrogate keys.

A surrogate key is a unique, system-supplied identifier used as the primary key of a relation. ...

Solution Summary

How are recursive relationships handled in database design?

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