Another way to design an information system is known as staged database design approach. It is a top-down approach. It begins by analyzing the general requirements of the organization: As the process continues, these problems are analyzed in more details. The steps in this approach are as follows:
Analyze User Environment:
The first step in designing a database is to understand and analyze the current user environment. The designer should closely study the current system and its outputs. He should also interview different users to know their current and future requirements.
Develop Logical Data Model:
After analyzing the user environment, the designer develops a logical data model for the organization. This data model consists of all entities, attributes and relationships. The designer also determines the following things:
• Types of applications and transactions
• Types of databases access
• Volume of transactions
• Volume of data
• Frequency of databases access
• Budgetary restrictions
• Performance requirements
Choose a DBMS:
The designer chooses a particular database management system on the basis of logical data model. The selected DBMS should satisfy all requirements and constrains identified in the logical data model.
Map Logical Model to DBMS:
The designer maps the logical data model to available data structure of the selected database management system.
Develop Physical Model:
The designer creates the exact layout of data according the facilities of selected DBMS and available resource of software and hardware.
Evaluate Physical Model:
The designer evaluates the physical model by checking the performance of applications and transactions. The designer may implement a particular portion of the database to validate the user views and to validate the performance effectively.
Perform Tuning:
Tuning is performed to improve the performance of database. Different modifications are made to the physical model if required.
Implement Physical Model:
If evaluation is satisfying then the designer implements the physical model and the database becomes functional.
Staged Database Design
The above figure shows that different steps can be repeated at different stages of the development process. For example, the database designer can review the user environment during the development logical model. While mapping the logical model to physical model, he can change his selection of DBMS. Similarly, if an error occurs and he has to tune the system, he may need to change the DBMS or remap the logical model. Even at the last step, he may review all steps from the very beginning.
comment closed