What are the steps for setting up foreign keys in a database?

The steps to set up foreign keys in a database are as follows:

1. Identify the tables where foreign keys need to be created and the tables they reference.
2. Ensure that the table referenced by the foreign key has a primary key or unique constraint.
3. To establish a foreign key constraint in the table, you can use either the ALTER TABLE or CREATE TABLE statement.
4. Specify the relationship between foreign key column and reference column when adding foreign key constraints, ensuring that the data type and length of the reference column match those of the foreign key column.
5. Ensure that the data types and lengths of the foreign key column and the referenced column match.
6. Ensure that there are no existing data violating foreign key constraints when adding a foreign key constraint, otherwise it will result in a failed addition of the foreign key.
7. After creating a foreign key, test that the foreign key constraint is functioning properly to ensure data consistency.