The relational database is the primary method for organizing and maintaining data today in information systems. it organizes data in two-dimensional tables with rows and columns called relations. in a database, is used to uniquely identify each record for retrieval or manipulation.

A key field is used to uniquely identify each record for retrieval or manipulation.

Explanation:

In a database there are many, having similar entities. So in order to differentiate each entity from other we need to set a key field among all the field which is always unique for each entity.

For example:

In a database of a company having data about its employees, the key field might be their ID. As some employees can have same names, addresses, phone numbers but cannot have the same ID.

answer6-9 screws;