May 2020
Beginner
564 pages
14h 9m
English
Content preview from Learn SQL Database Programming
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Referential integrity
Referential integrity refers to the consistency and accuracy between tables that can be linked together. By having a primary key on the parent table and a foreign key on the child table, you achieve referential integrity. A foreign key on the child table creates a link between one or more columns in the child table and the primary key on the parent table. When a foreign key is present, it must reference a valid, existing primary key in the parent table. This way, the data in both tables can maintain a proper relationship. You will learn more about this in the following example.
If you don't set up referential integrity, you wind up with orphaned records. For example, let's say that you delete a player from the first ...
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