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``Integrity constraints'' are things like:
- ``primary key''
- It is a value of a column in a row in a table
- It is a unique identifier of a row in a table
- A primary-key constraint implies the values
of that column of that table are unique
- ``foreign key''
- It is a value of a column in a row in a table
- It is a unique identifier of a row in a second table
- A foreign-key constraint implies the existence of
that row in the second table
What are the primary keys and foreign keys
in our ``genpepts'' and ``features'' tables?
Wong Lim Soon
4/9/2000