One or more columns (fields) in a relational database that can uniquely identify a row in the table. If there are two or more candidate keys, only one is selected as the "primary." See primary key.

Everyone knows what a simple database is: Telephone directories, mail-order catalogs and dictionaries are all databases of sorts. Databases can be structured or organized in several different ways: as ...

One of the principles within relational theory is that each entity’s row or tuple be uniquely identifiable. This means the defined structure includes some combination of attributes whose populated ...

Excel possesses formidable database powers. Creating a relational database starts with a Master table that links it to subordinates, called (awkwardly) Slave, Child, or Detail tables. Before we dive ...