adplus-dvertising
frame-decoration

Question

An entity has:

(i) a set of properties
(ii) a set of properties and values for all the properties
(iii) a set of properties and the values for some set of properties may non-uniquely identify an entity
(iv) a set of properties and the values for some set of properties may uniquely identify an entity

Which of the above are valid?

a.

(i) only

b.

(ii) only

c.

(iii) only

d.

(iv) only

Answer: (d).(iv) only

Engage with the Community - Add Your Comment

Confused About the Answer? Ask for Details Here.

Know the Explanation? Add it Here.

Q. An entity has: (i) a set of properties (ii) a set of properties and values for all the properties (iii) a set of properties and the values for some set of properties may...

Similar Questions

Discover Related MCQs

Q. Aggregation is:

Q. Suppose R is a relation schema and F is a set of functional dependencies on R. Further, suppose R1 and R2 form a decomposition of R. Then the decomposition is a lossless join decomposition of R provided that:

Q. In a heap, every element is …………… of all the elements in the subtree.

Q. A superkey for an entity consists of:

Q. Which of the following set of keywords constitutes a mapping in SQL?

Q. If a relation is in 2NF then:

Q. Which of the following is true ?

Q. Consider the query : SELECT student_name FROM student_data WHERE rollno (SELECT rollno FROM student_marks WHERE SEM1_MARK=SEM2_MARK);

Which of the following is true?

Q. A primary key for an entity is:

Q. Aggregate functions in SQL are:

Q. If a relation is in 2NF and 3NF forms then:

Q. The end of an SQL command is denoted by:

Q. Consider  the  query  :  SELECT  student_name  FROM  students  WHERE class_name=(SELECT  class_name  FROM  students  WHERE  math_marks=100); what will be the output ?

Q. Which of the following statements is wrong?

Q. A recursive foreign key is a:

Q. A sub class having more than one super class is called:

Q. A relation R={A,B,C,D,E,F} is given with following set of functional dependencies:

F={A→B,AD→C,B→F,A→E}.

Which of the following is Candidate Key?

Q. Which statement is false regarding data independence?

Q. In DBMS, deferred update means:

Q. Which statement is false regarding data independence ?