Question

Briefly explain about any two column constraints used in SQL.

Hint:

Column constraints are essential for maintaining data integrity and ensuring that only valid data is inserted into the table.

Answer 1

Step 1: Define Column Constraints.
Column constraints are used to define the properties or rules applied to the columns in a database table to ensure the integrity and accuracy of the data. The constraints are applied at the column level.
Step 2: Explain the constraints.
Two common column constraints used in SQL are: (1) NOT NULL:
This constraint ensures that a column cannot have a NULL value. It is used when we want to ensure that every row in the table must have a value for this column. (2) UNIQUE:
The UNIQUE constraint ensures that all the values in a column are different from each other. It is used when we want to ensure that no duplicate values are entered in that column.