SQL Constraints MCQ NOT NULL UNIQUE CHECK Practice Questions

Direction: Choose the correct option

What are constraints in SQL?

A. Indexes

B. Rules enforced on data

C. Column types

D. Table names

Direction: Choose the correct option

Which constraint ensures a column cannot have NULL values?

A. NOT ZERO

B. NULL CHECK

C. NOT NULL

D. NO NULL

Direction: Choose the correct option

CREATE TABLE products (
    price DECIMAL CHECK (price > 0)
);

What constraint is applied?

A. Not null

B. Foreign key

C. Check constraint

D. Unique constraint

Direction: Choose the correct option

What does DEFAULT constraint do?

A. Ensures uniqueness

B. Creates index

C. Sets default value for column

D. Prevents duplicates

Direction: Choose the correct option

Which constraint ensures all values in a column are different?

A. DIFFERENT

B. PRIMARY KEY

C. DISTINCT

D. UNIQUE

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