Originally Posted by kihrer
In database terms the team would be the primary key and the members of the team would be the secondary key. Your primary key must be unique. A primary may have any number of associated secondary keys.
Not to be jerky, but this is not correct. In database terms, a team and a member would each be an entity or table. The table would then have attributes defined in it. One such attribute would be a unique, non-null value, the primary key. Other attributes could be the name of each. Each non-key attribute should depend on the primary key to be normalized at a certain level (3NF). Each entry in the table is called a tuple, and each tuple must have a primary key. Over the years, tuple/attribute have been displaced by record/field, and then again by row/column. Each entity can be associated to another through the use of relations. Relations are generally either defined by a foreign key reference (1:∞) or by a seperate table with foreign keys to each of the related ones (∞:∞).