Question

write true or false

1)It is possible to store null value directly in MySQL.

2)In Relational Algebra, the UNION operator is a unary operator.

3)n SQL, it is possible to insert multiple rows into a table using a single INSERT statement.

4)R has 5 rows and S has 6 rows. It is possible for R |x| S to have 30 rows.

5)R has 5 rows and S has 6 rows. It is possible for R |x| S to have 21 rows.

6)Relations R and S have four and five tuples respectively. It is not possible that R |x| S to have 0 tuple.

7)R has 4 rows and S has 5 rows. It is possible for R |x| S to have 19 rows.

8)The query design wizard in Microsoft’s Access is based on Relational Calculus.

Answer 1

1: False: If there is a NOT NULL constraint in the column while it is created then you cannot store NULL values. But if there is no such constraint you can store NULL values. MySQL stores NULL value by default.

2: False: Since a UNION  performs binary union between two given relations it is a binary operation.

3 True, In order to add the multiple rows to a table at once, use the INSERT statement:

4  True, R (x) S will have 30 rows

5  False, R (x) S will have 30 rows

6  False

7  False, R (x) S will have 20 rows

8. True, Query can be designed to specify the fields from the table and the constraints based on which the results are generated.

******************************************************************************************
PLEASE LIKE IT RAISE YOUR THUMBS UP
IF YOU ARE HAVING ANY DOUBT FEEL FREE TO ASK IN COMMENT SECTION
******************************************************************************************