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MySQL CHECK Constraint

The CHECK constraint ensures that the values in a column meet a specific condition.

Example with Tamil Kings

CREATE TABLE tamil_kings_check (
    id INT AUTO_INCREMENT PRIMARY KEY,
    reign_years INT CHECK (reign_years > 0)
);

Code Explanation: The CHECK constraint ensures that the reign_years value is greater than 0, meaning a king must have ruled for at least one year.

Best Practices

  • Use the CHECK constraint to enforce rules on column values.
  • Ensure that constraints do not conflict with valid data.

Key Takeaways

  • The CHECK constraint enforces data validation at the database level.
  • It is useful for maintaining data consistency and integrity.
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