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What is TRUE about NOT NULL Constraint?

6. What is TRUE about NOT NULL Constraint?

1. In columns that are subject to the NOT NULL constraint, duplicate values are not allowed.
2. When a table's column is declared as NOT NULL, no record in the table can have an empty value for that column.
3. By applying the NOT NULL constraint, we will always ensure that the column contains a unique value and won't allow nulls.
4. The value will first be checked for certain conditions before inserting it into the column when a NOT NULL constraint applies to a column in the table.

Answer: B) When a table's column is declared as NOT NULL, no record in the table can have an empty value for that column

Explanation:

When a table's column is declared as NOT NULL, no record in the table can have an empty value for that column.