Question

A __________ value is specified for the column, if no value is provided.

• A. unique
• B. null
• C. default
• D. primary

Hint:

Always use DEFAULT for automatic values (e.g., DEFAULT 0 or DEFAULT 'Unknown') when no value is supplied.

Answer 1

The Correct Option is C

Step 1: Recall concept of default value.
In SQL, when creating a table, a column can be assigned a DEFAULT value. This value is automatically used if no explicit value is provided during data insertion.
Step 2: Evaluate options.
- Unique: A constraint that mandates distinct values in a column; it does not provide a fallback value.
- Null: Represents the absence of a value; it is not automatically assigned unless explicitly permitted.
- Default: A predetermined value that is inserted when no other value is supplied.
- Primary: Refers to the primary key constraint, which is not relevant to this scenario.
Final Answer: \[\boxed{\text{Default value is specified if no value is provided.}}\]