The values appearing in given attributes of any tuple in the referencing relation must likewise occur in specified attributes of at least one tuple in the referenced relation, according to _____________________ integrity constraint.
A. Referential
B. Primary
C. Referencing
D. Specific
Answer:A
The values appearing in given attributes of any tuple in the referencing relation must likewise occur in specified attributes of at least one tuple in the referenced relation, according to _____________________ integrity constraint.
A. Referential B. Primary C. Referencing D. Specific
Explanation: Consider 2 relations r1 and r2. r1 may include among its attributes the primary key of relation r2. This attribute is called a foreign key from r1, referencing r2. The relation r1 is also called the referencing relation of the foreign key dependency, and r2 is called the referenced relation of the foreign key.