Question

In order to include an attribute Name to the teaches relation which of the following command is used? (a) Alter table teaches include Name; (b) Alter table teaches add Name; (c) Alter table teaches add Name varchar; (d) Alter table teaches add Name varchar(20); I had been asked this question in an international level competition. The question is from Querying database part-1 DDL in section Database Systems Design and Implementation of Database Management Select the correct answer from above options Interview Questions and Answers, Database Interview Questions and Answers for Freshers and Experience

Answer 1

Right choice is (d) Alter table teaches add Name varchar(20); Easy explanation - The form of the alter table command is alter table r add AD; where r is the name of an existing relation, A is the name of the attribute to be added, and D is the type of the added attribute.