MySQL All Constraints

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What is Data Integrity in MySQL?

Constraints in MySQL are rules applied to columns or tables to ensure data integrity and consistency by enforcing conditions such as uniqueness, referential integrity, and allowable values. They act as guardians to keep data organized and accurate according to predefined rules.

What is Data Integrity in MySQL?

Data integrity in MySQL ensures that data remains accurate, consistent, and reliable throughout its lifecycle, enforced through mechanisms like constraints and rules to prevent unauthorized or incorrect modifications.

Why do we need Constraints?

Constraints are needed in databases like MySQL to ensure data accuracy, enforce business rules, prevent redundancy, maintain referential integrity, and enhance data security.

What are the different types of Constraints available in MySQL?

MySQL supports the following six types of constraints for maintaining data integrity.

  1. NOT NULL Constraint
  2. UNIQUE KEY Constraint
  3. Default Constraint
  4. CHECK KEY Constraint
  5. PRIMARY KEY Constraint
  6. FOREIGN KEY Constraint.

Imposing Constraint in MySQL:

We can impose constraints on a table in two different ways

  1. Imposing constraints on Column level
  2. Imposing constraints on Table level
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