Database Design for Mere Mortals™: A Hands-On Guide to Relational Database Design, Second Edition

Table-Level Integrity

This type of integrity is a major component of overall data integrity, and it ensures the following:

• There are no duplicate records in a table.

• The primary key exclusively identifies each record in a table.

• Every primary key value is unique.

• Primary key values are not null.

You began establishing table-level integrity when you defined a primary key for each table and ensured its enforcement by making absolutely certain that each primary key fully complied with the Elements of a Primary Key. In the next chapter, you'll enhance the table's integrity further as you establish field specifications for each field within the table.