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

In a relational database, keys ensure that any record in a table can be uniquely identified by one field or a combination of fields in the table. Keys also link tables in the database together and ...

Our team tests, rates, and reviews more than 1,500 products each year to help you make better buying decisions and get more from technology. Databases don't have to be complicated. Our guide to these ...