gs gs115 SQL Constraints - SQL Unique Constraint - Quiz No.1
gs gs115 Structured Query Language Quiz
This quiz belongs to book/course code gs gs115 Structured Query Language of gs organization. We have 79 quizzes available related to the book/course Structured Query Language. This quiz has a total of 5 multiple choice questions (MCQs) to prepare and belongs to topic SQL Constraints. NVAEducation wants its users to help them learn in an easy way. For that purpose, you are free to prepare online MCQs and quizzes.
NVAEducation also facilitates users to contribute in online competitions with other students to make a challenging situation to learn in a creative way. You can create one to one, and group competition on an topic of a book/course code. Also on NVAEducation you can get certifications by passing the online quiz test.
Question 1: In SQL, which of the following constraint can be used to ensure that all the values in a column are different?
PRIMARY KEY
UNIQUE
NOT NULL
CANDIDATE KEY
Question 2: Which of the following statement can be used to apply the UNIQUE constraint to a column?
CREATE TABLE table_name ( column1 datatype UNIQUE, column2 datatype UNIQUE, ... columnn datatype UNIQUE));CREATE TABLE table_name ( UNIQUE column1 datatype, UNIQUE column2 datatype, ... UNIQUE columnn datatype));CREATE TABLE table_name UNIQUE ( column1 datatype, column2 datatype, ... columnn datatype));CREATE TABLE table_name ( column1 datatype, column2 datatype, ... columnn datatype, UNIQUE (column1, column2, …,columnn));
Question 3: Which of the following statement can be used to apply the UNIQUE constraint to a column of an existing table?
ALTER TABLE table_name ADD (column_name) UNIQUE;ALTER TABLE table_name UNIQUE (column_name);ALTER TABLE table_name ADD UNIQUE (column_name);ALTER TABLE table_name ADD UNIQUE;
Question 4: Which of the following statement can be used to apply the UNIQUE constraint to multiple columns of an existing table?
ALTER TABLE table_name ADD CONSTRAINT UNIQUE (column1,column2,…,columnn);ALTER TABLE table_name ADD constraint_name UNIQUE (column1, column2,…,columnn);ALTER TABLE table_name CONSTRAINT constraint_name UNIQUE (column1,column2,…,columnn);ALTER TABLE table_name ADD CONSTRAINT constraint_name UNIQUE (column1,column2,…,columnn);
Question 5: Which of the following statement can be used to delete the UNIQUE constraint from a column?
ALTER TABLE table_name DROP constraint_name;ALTER TABLE table_name DROP INDEX constraint_name;ALTER TABLE table_name DROP INDEX UNIQUE;ALTER TABLE table_name DROP UNIQUE;
