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3. The subset of a super key is a candidate key under what condition?
Choose the correct option:

  • a) No proper subset is a super key

  • b) All subsets are super keys

  • c) Subset is a super key

  • d) Each subset is a super key

The subset of a set cannot be the same set. Candidate key is a set from a super key which cannot be the whole of the super set.

10. A _________ integrity constraint requires that the values appearing in specified attributes of any tuple in the referencing relation also appear in specified attributes of at least one tuple in the referenced relation.
Choose the correct option:

  • a) Referential

  • b) Referencing

  • c) Specific

  • d) Primary

A relation, say r1, may include among its attributes the primary key of another relation, say r2. This attribute is called a foreign key from r1, referencing r2. The relation r1 is also called the referencing relation of the foreign key dependency, and r2 is called the referenced relation of the foreign key.

2. Student(ID, name, dept name, tot_cred)
Choose the correct option:

  • In this query which attributes form the primary key?

  • a) Name

  • b) Dept

  • c) Tot_cred

  • d) ID

The attributes name, dept and tot_cred can have same values unlike ID.

2. Which one of the following provides the ability to query information from the database and to insert tuples into, delete tuples from, and modify tuples in the database?
Choose the correct option:

  • a) DML(Data Manipulation Langauge)

  • b) DDL(Data Definition Langauge)

  • c) Query

  • d) Relational Schema

DML performs the change in the values of the relation.

a) Salary*1.1
Choose the correct option:

  • b) ID

  • c) Where

  • d) Instructor

Where selects the rows on a particular condition. From gives the relation which involves the operation. Since Instructor is a relation it has to have from clause.

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