Question

Please answer true or false

27) Relationship instances occur when an instance of one entity is related to an instance of another entity via a relationship.

28) Two columns of a relational table can have the same values.

29) If one of two identical relational tables has the first row moved to the last place, those two relational tables are no longer identical.

30) An entity and its 1:1 unary relationship are mapped as one relation.

31) An entity and its M:N unary relationship are mapped as one relation.

32) The relation resulting from mapping a weak entity (with a 1:M identifying relationship) has a composite primary key that is composed of the partial identifier and a foreign key corresponding to the primary key of the owner entity.

33) Every attribute appears only once in an ER diagram

34) A restriction specifying that no salary entered in the salary column can be higher than $300,000 is an example of a business rule.

Answer 1

27) True
28) True
29) False
30) True
31) False
32) True
33) True
34) True