Integrity Constraints

Integrity constraints (also referred to as just constraints) are logical conditions on the data of an application. They may take many different forms.

Property constraints

The most important type of constraint, property constraints, define conditions on the admissible property values of an object. They are defined for an object type or class, so they apply to all objects of that type. We’ll concentrate on the most important cases of property constraints:

• String length constraints: These require that the length of a string value for an attribute is less than a certain maximum number or greater than a minimum number.
• Mandatory value constraints: These

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