DATA PROCESSING SSS2 FIRST TERM           

WEEK 9

NORMAL FORM III

Contents

KEY

A key is an attribute or field that can be used to identify a record in a database table or file.

The Primary Key is a unique attribute that can be used to identify a record in a database table. For Example, in the student database table above, the attribute that is unique to identify each record is the Student ID or Reg No.

CONCEPTS OF FOREIGN KEY

A foreign key is a field in a relational table that matches a candidate key of another table. A foreign key (FK) is a column or combination of columns that are used to establish and enforce a link between the data in two tables. You can create a foreign key by defining a FOREIGN KEY constraint when you create or modify a table. The foreign key can be used to cross-reference the table. The.... View More