What can be established by setting up a foreign key constraint?

Setting up a foreign key constraint establishes a relationship between tables in a database. A foreign key in one table points to the primary key in another table, which helps maintain referential integrity. This relationship ensures that the data in the tables is consistent; for instance, a record in a child table cannot reference a non-existent record in the parent table. This linkage is crucial in relational databases for logically connecting related data and enforcing data integrity.

In contrast, other choices do not reflect the primary function of a foreign key constraint. Data duplication pertains to the unnecessary repetition of data within a database, which foreign key constraints are designed to mitigate by ensuring proper relationships. Field validation involves checking that the data entered into a field meets specific rules or constraints, but this is usually managed by other types of constraints, such as check constraints. User permissions define access controls and are managed by security settings rather than through foreign key relationships.