Final answer:
The notion that referential integrity must be enforced by the application program is false. Referential integrity constraints are enforced at the database level through foreign key constraints, which ensure consistent relationships between tables.
Step-by-step explanation:
The statement 'Referential integrity constraints must be enforced by the application program' is false. Referential integrity constraints are a fundamental concept in relational database management systems (RDBMS) and are typically enforced at the database level, not by the application program. The database system is responsible for maintaining the consistency and correctness of the data whenever insert, update, or delete operations are performed. The database does this by following the rules set by the referential integrity constraints, which ensure that relationships between tables remain consistent.
How Referential Integrity is Enforced
Referential integrity constraints are enforced through foreign key constraints within the database itself. When a foreign key exists in one table that references the primary key of another table, the database will not allow a row to be entered or modified in the child table if it contains a foreign key value that does not exist in the corresponding parent table. This ensures that there are no orphan records. For example, if you have a 'Books' table and an 'Authors' table where each book must be associated with an author, the 'Books' table will have a foreign key referencing the 'Authors' table.
While it is possible for application programs to implement additional logic for data integrity, it is more efficient, secure, and reliable to rely on the mechanisms provided by the RDBMS to enforce referential integrity. This is because the RDBMS has been designed specifically for this purpose and can enforce these rules consistently and without fail, no matter how the data is accessed or which application is used.