What are the different types of constraints in MySQL?

There are several types of constraints in MySQL:

1. Primary Key Constraint: It is used to define one or more columns as the primary key of a table, which uniquely identifies each row in the table.
2. Unique Constraint: Ensures that the values in a single column or multiple columns are unique in a table and does not allow duplicates.
3. Foreign Key Constraint is used to ensure that the values in one or more columns in a table are related to the values in one or more columns in another table.
4. Not Null Constraint: Used to ensure that the value of a certain column cannot be empty, meaning it cannot be null.
5. Default Constraint is used to specify the default value of a column. If a new row is inserted without specifying a value for that column, the default value will be used.
6. Check Constraint is used to specify the range of values or conditions that a column must adhere to.

These constraint types can be used individually or in combination.