There are two categories of integrity constraints: General constraints, which allow you to restrict the data values that are accepted for the variables in a single data file, such as requiring that ...

A primary key is a field used to uniquely identify every record in the database. Sometime primary keys are obvious, for example a car license plate could be used to uniquely identify cars. Often, ...

I have a foreign key constraint that I created to reference the primary key of another table:<BR><BR><pre class="ip-ubbcode-code-pre">constraint geneassay_fk foreign ...