Labels:book | chat room | hakham | monitor | reckoner | sky OCR: 634 SECTION CHAPTER 11 What makes each record unique? Although two people might have the same name or two paychecks might contain the same amount, com- puter must have some way to differentiate between records. A Aprimary key is a field that contains data unique to record Designers commonly desig- nate fields such as CheckNumber, SocialSecurityNumber, and PartNumber as primary keys How does database designer know what data types to use? The data that can be entered into field depends on the field's data type From technical perspective data type specifies the way data is repre- sented on the disk and in RAM From user perspective, the data type determines the way data can be manipulated When designing database each field is assigned data type Data can be broadly classified as numeric or char ...
