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

Question

Given table 'StudAtt' with structure as (Rno, Attdate, Attendance). Identify the suitable command to add a primary key to the table after creation.
Note: We want to make both Rno and Attdate columns as primary key.

Answer 1

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: \[\boxed{\text{Default value is specified if no value is provided.}}\]

List-I	List-II
(A) SUBSTR()	(II) To extract a substring from a string.
(B) TRIM()	(IV) To remove spaces from both sides of the string.
(C) INSTR()	(I) To find the position of a substring in a string.
(D) LEFT()	(III) To extract characters from the left side of the string.

ENO	SALARY
A101	4000
B109	NULL
C508	6000
A305	2000

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

Show Hint

The Correct Option is C

Solution and Explanation

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