Databases: Their Role and Components

The relationships between information systems and their respective databases are very important. Information systems serve as the root for all management of data as well as using the data to create manageable and usable information. Ultimately, the design of the information system will in turn help with the design of the database. The database design should reflect the needs of the information system. In order to be successful the design must recognize itself as part of a larger system.

Both the Systems Development Life Cycle and the Database Life cycle function similarly. Both cycles involve some level of planning, design, implementation and maintenance. The purpose of the SDLC is to create the information system that will serve as the outline for data and information needs. By developing the SDLC, the DBLC can be mapped out more accurately.

As one life cycle is a part of another, both systems must accommodate each other. It is the responsibility of the SDLC in the analysis and design phases to identify the necessary databases that will be designed using the DBLC. It must also be able to accommodate changes/additions/removals to possible data management systems. The initial study for the DBLC is where the designer identifies the scope in relation to the SDLC. A good DBLC always keeps the bigger picture in mind.

There are two important design strategies.

Top-down design begins with identifying the data sets then defines the elements for each data set.

Bottom-up design begins by identifying the required data elements then creates the necessary data sets.

What does the acronym SDLC mean, and what does an SDLC portray?

Systems Development Life Cycle (SDLC) - the life cycle of the information system. The purpose of the SDLC is to create the information system that will serve as the outline for data and information needs.

What does the acronym DBLC mean, and what does a DBLC portray?

Database Life Cycle (DBLC) - the life cycle of a database system. The purpose of the DBLC is to take a database from initial study phase all the way to full operation. The DBLC should recognize the scope of the SDLC and adjust design accordingly.

Discuss the distinction between centralized and decentralized conceptual database design.

Centralized and decentralized database designs are based on the scope of the planned database. Centralized design is geared towards a simpler environment. When the needs of an organization are confined to a smaller scope or fewer problems to address, this approach can be successful. When a database requires a much more complex environment, a decentralized design approach is appropriate. Decentralized design is useful for complex operations to address numerous problems that may span many areas of an organization.

Discuss the distinction between top-down and bottom-up approaches to database design.

As seen in the previous question in regards to these two approaches, the difference lies in the order of identification of the data sets and their elements. The selection of either approach can very based on scope or personal preference (Rob & Coronel, 2007, p. 387). If a designer's focus was one a small database with few entities and attributes, the bottom-up approach may be more logical. In the case of complex databases, it is often the top-down method that is most advantageous.