Consider the followings in choose the primary key: The primary key shall be simple and familiar, e. The specification is a formal representation of what a system should do, expressed in terms that are independent of how it may be realized.
They also created easy to use forms for inputting data and a user-friendly switchboard for easy navigation.
For an implementation with a relational DBMS, this will probably involve the use of SQL to create tables and constraints that satisfy the logical schema description and the choice of appropriate storage schema if the DBMS permits that level of control.
Each OrderDetails item specified one product.
So it is important that the designer has prioritized these properties usually using information from the requirements specification ; for example, to decide if integrity is more important than efficiency and whether usability is more important than flexibility in a given development.
This kind of relationship is known as many-to-many. It is during this design activity that choices are made as to which tables are most appropriate for representing the data in a database.
The types of relationship include: one-to-many one-to-one One-to-Many In a "class roster" database, a teacher may teach zero or more classes, while a class is taught by one and only one teacher.