1. What is a relation? Differentiate between a relation schema and a relation instance. Define the terms arity and degree of a relation. What are domain constraints?
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2. What SQL construct enables the definition of a relation? What constructs allow modification of relation instances?
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3. What are integrity constraints? Define the terms primary key constraint and foreign key constraint. How are these constraints expressed in SQL? What other kinds of constraints can we express in SQL?
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4. What does the DBMS do when constraints are violated? What is referential integrity? What options does SQL give application programmers for dealing with violations of referential integrity?
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5. When are integrity constraints enforced by a DBMS? How can an application programmer control the time that constraint violations are checked during transaction execution?
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6. What is a relational database query?
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7. How can we translate an ER diagram into SQL statements to create tables? How are entity sets mapped into relations? How are relationship sets mapped? How are constraints in the ER model, weak entity sets, class hierarchies, and aggregation handled?
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8. What is a view? How do views support logical data independence? How are views used for security? How are queries on views evaluated? Why does SQL restrict the class of views that can be updated?
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9. What are the SQL constructs to modify the structure of tables and destroy tables and views? Discuss what happens when we destroy a view.
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3.1 Define the following terms: relation schema ,relational database schema, domain, relation instance, relation cardinality, and relation degree.
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3.2 How many distinct tuples are in a relation instance with cardinality 22?
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3.3 Does the relational model, as seen by an SQL query writer, provide physical and logical data independence? Explain.
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3.4 What is the difference between a candidate key and the primary key for a given relation? What is superkey?
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3.5 consider the instance of the Students relation shown in Figure 3.1.
1 Give an example of an attribute (or set of attributes) that you can deduce is not a candidate key, based on this instance being legal.
2. Is there any example of an attribute (or set of attributes) that you can deduce is a candidate key, based on this instance being legal?
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3.6 What is a foreign key constraint? Why are such constraints important? What is referential integrity?
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3.7 Consider the relations Students, Faculty, Courses, Rooms, Enrolled, Teaches, and Meets_In defined in Section 1.5.2.
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