Lecture 20

Question 1

SQL for inserting

Answer 1

INSERT INTO EMPLOYEE(Name, SSN)
SELECT Pname, Pssn FROM PERSON

Question 2

how to delete table SQL

Answer 2

DROP TABLE EMPLOYEE

Question 3

how to delete the column from table SQL

Answer 3

ALTER TABLE EMPLOYEE
DROP COLUMN Name CASCADE

Question 4

how to add a new column to table SQL?

Answer 4

ALTER TABLE EMPLOYEE
ADD COLUMN Hobby VARCHAR(10) DEFAULT ‘NA’

Question 5

how to modify default value for attribute

Answer 5

ALTER TABLE EMPLOYEE ALTER COLUMN Hobby DROP DEFAULT
SET DEFAULT ‘Football’

Question 6

how to add constraint in SQL

Answer 6

ALTER TABLE EMPLOYEE
ADD CONSTRAINT constraint_name UNIQUE(Name)

Question 7

how to delete the records with particular value

Answer 7

DELETE FROM EMPLOYEE
WHERE Value=‘Cho-to-tam’

Question 8

How to set the value of attribute to something for the employee with key = 1234

Answer 8

UPDATE EMPLOYEE
SET Attribute=‘something’
WHERE SSN=1234