A key is a
column or combination of columns that identifies a row of data as unique in a
relational database table. Business rules can impact the assignment of table
keys.
For example, because Shear Style has no customers with
the same exact name, the key field
for the Customer Table is
Owner Name. However, if this were not the case, the combination
of Owner Name and Phone
may be needed to uniquely identify a row of data in the Customer Table.
