Referential integrity states that:. A. Something assigned to an attribute when no other value applies (N/A) or when the applicable value is unknown;
B. Values of an attribute must be taken from a pre-defined domain;
C. No primary key attribute (or component of a primary key) can be null;
D. Each foreign key value MUST match a primary key value in another relation or the foreign key value must be null;

D. Each foreign key value MUST match a primary key value in another relation or the foreign key value must be null.

Explanation:

In Computer programming, integrity constraints can be defined as a set of standard rules that ensures quality information and database are maintained.

Basically, there are four (4) types of integrity constraints and these are;

1. Key constraints.

2. Domain constraints.

3. Entity integrity constraints.

4. Referential integrity constraints.

Referential integrity states that each foreign key value must match a primary key value in another relation or the foreign key value must be null.

For instance, when a foreign key in Table A points to the primary key of Table B, according to the referential integrity constraints, all the value of the foreign key in Table A must be null or match the primary key in Table B.

Hence, the referential Integrity constraints ensures that the relationship between the data in a table is consistent and valid.

you already know many words that you use every day as part of your writing and you probably also know that certain words fit better in certain situations. tonight she will , sit) down and , write) a cover letter to when writing, you need to choose the correct word according to its spelling and

answeroperating system;