How to communicate foreign key constraints in a business application?

1. What are the constraints for foreign key?
2. How do you resolve a foreign key constraint error?
3. How can the key and foreign key constraints be enforced by the DBMS using SQL?
4. How are foreign constraints helpful?

What are the constraints for foreign key?

A foreign key is a column (or combination of columns) in a table whose values must match values of a column in some other table. FOREIGN KEY constraints enforce referential integrity, which essentially says that if column value A refers to column value B, then column value B must exist.

How do you resolve a foreign key constraint error?

The error message itself showing there is a foreign key constraint error, which means you are deleting a parent table where the child table contains the Primary table identifier as a foreign key. To avoid this error, you need to delete child table records first and after that the parent table record.

How can the key and foreign key constraints be enforced by the DBMS using SQL?

To successfully change or delete a row in a foreign key constraint, you must first either delete the foreign key data in the foreign key table or change the foreign key data in the foreign key table, which links the foreign key to different primary key data.

How are foreign constraints helpful?

The FOREIGN KEY constraint is crucial to relational database design. It lets us link the data according to our needs. As it creates some dependencies between the columns of primary and foreign tables, it also lets us decide what to do ON UPDATE and ON DELETE actions performed on the rows of the primary table.