[Solved] Which of the following is the correct syntax to add a foreign key with ON DELETE SET NULL in SQL? — Ans: FOREIGN KEY (child_id) REFERENCES parent(id) ON DELETE SET NULL | SQL

SQL - Table Constraints

Which of the following is the correct syntax to add a foreign key with ON DELETE SET NULL in SQL?

AFOREIGN KEY (child_id) REFERENCES parent(id) ON DELETE CASCADE

BFOREIGN KEY (child_id) REFERENCES parent(id) ON DELETE SET NULL

CFOREIGN KEY (child_id) REFERENCES parent(id) ON DELETE RESTRICT

DFOREIGN KEY (child_id) REFERENCES parent(id) ON DELETE NO ACTION

Step-by-Step Solution

Solution:

Step 1: Identify the syntax for ON DELETE SET NULL
The correct syntax includes the phrase ON DELETE SET NULL after the foreign key reference.
Step 2: Match options with syntax
FOREIGN KEY (child_id) REFERENCES parent(id) ON DELETE SET NULL exactly matches the required syntax for setting foreign keys to NULL on parent deletion.
Final Answer:
FOREIGN KEY (child_id) REFERENCES parent(id) ON DELETE SET NULL -> Option B
Quick Check:
ON DELETE SET NULL syntax = FOREIGN KEY (child_id) REFERENCES parent(id) ON DELETE SET NULL [OK]

Quick Trick: Look for 'ON DELETE SET NULL' phrase exactly [OK]

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Which of the following is the correct syntax to add a foreign key with ON DELETE SET NULL in SQL?