Prevent deleting parent rows when children exist

Prevent deleting parent rows when children exist

Medium SQL Constraints 25 views
Explanation Complexity

Problem Statement

In Orders(order_id) and Payments(payment_id, order_id), enforce that an order cannot be deleted if it has payments.

Input Format

SQL DDL

Output Format

DDL statement(s)

Example

Orders, Payments
FK created

Constraints

Assume Orders exists

Input / Output Format

Input Format
SQL DDL
Output Format
DDL statement(s)
Constraints
Assume Orders exists

Examples

Input:
Orders, Payments
Output:
FK created

Example Solution (Public)

SQL 
ALTER TABLE Payments ADD CONSTRAINT fk_payments_orders FOREIGN KEY (order_id) REFERENCES Orders(order_id) ON DELETE RESTRICT;

Official Solution Code

ALTER TABLE Payments ADD CONSTRAINT fk_payments_orders FOREIGN KEY (order_id) REFERENCES Orders(order_id) ON DELETE RESTRICT;
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