Systems analysis and design

ID # Candi Keys “ A candi key is a column or multiple columns, which can describe the database record in unique form. A single relation can have multiple candidate keys” (Janssen). In this project the candidate that can be used to uniquely identify the records of the database are stock number, vehicle number and model. With these candidate keys, a user can uniquely identify the records of the database:
Serial Number
Candidate Keys
01
Stock Number
02
Vehicle Number
03
Model
Primary Keys
“ A primary key is the key through which users can uniquely identify the each record of the relation. In one relation there is only one primary key” (Chapple). In this project the primary key that can be used for the uniquely identification of whole record is stock number for stock relation, vehicle number for vehicle relation.
Serial Number
Primary Keys
01
Stock Number
02
Vehicle Number
Foreign Keys
Foreign key is also a primary key but it can be used in other relation for collecting information. This is known as primary key (sybase). In this project the foreign keys that can be used are stock number, vehicle number and model:
Serial Number
Primary Keys
01
Stock Number
02
Vehicle Number
03
Model
Secondary keys
In a relation there are several options for the selection of primary keys. In this scenario, the keys that are selected is known as primary key, and other keys are secondary keys and both of the these collectively known as secondary keys (programmerinterview. com). In this project following can be selected as the secondary keys.
Serial Number
Secondary Keys
01
Stock Number
02
Vehicle Number
03
Model

Works Cited
Chapple, Mike. DATABASES CATEGORIES. 13 02 2015. .
Janssen, Cory. Candidate Key. 13 02 2015. .
programmerinterview. com. What is the definition of a secondary key? 13 2 2015. .
sybase. Foreign Key Example. 13 02 2015. .