Review Questions

1.What is relation? What are primary, candidate and foreign keys?
2.What are the Codd’s twelve rules? Describe in detail.
3.Describe the SELECT operation. What does it accomplish?
4.Describe the PROJECT operation. What does it accomplish?
5.Describe the JOIN operation. What does it accomplish?
6.Let us consider the following relations as shown in Fig. 5.22 below.
Fig. 5.22. Relations

With reference to the above relations display the result of the following commands:

  1. Select tuples from the CUSTOMER relation ...

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