More Constraints
Let’s learn about a few more types of constraints.
We'll cover the following...
Referential integrity constraints
A referential integrity constraint requires that the values of a reference property refer to an object that exists in the population of the property’s range class. Since we don’t deal with reference properties in this chapter, we’ll postpone the discussion of referential integrity constraints to the chapter on Associations](https://www.educative.io/collection/page/10370001/5397377793392640/5022490478247936).
Frozen and read-only value constraints
A frozen value constraint defined for a property requires that the value of this property must not be changed after it has been assigned. This ...