What is the purpose of a foreign key relationship between two tables in the ABAP Dictionary?

The purpose of a foreign key relationship between two tables in the ABAP Dictionary is primarily to ensure the integrity of data in the corresponding database tables. A foreign key relationship establishes a relationship between a primary key in one table and a corresponding foreign key in another table. This serves to maintain referential integrity, meaning that any value in the foreign key field must correspond to a valid existing value in the primary key field of the related table.

This type of relationship helps to prevent orphaned records and ensures that the data remains cohesive and meaningful across the tables. It obligates the database to enforce rules that ensure that the relationships between entities remain consistent, thus safeguarding the integrity of the data stored.

While documentation may support understanding the relationship and enforcing data uniqueness can be an aspect, the primary and most critical function of foreign key relationships is data integrity across tables in relational databases.