Planning, Design and Administration

The software has now exceeded hardware as the key to the success of many computer-based systems. Unfortunately, the track record of software development is not particularly remarkable. The last few decades have seen the rise in software applications ranging from small, relatively simple applications consisting of a few lines of code, to large, complex applications consisting of millions of lines of code. Many of these applications have required stable maintenance which involved correcting faults that had been detected, implementing new user requirements, and modifying the software to run on new or upgraded platforms.

The effort spent on upholding the design and quality began to absorb resources at an alarming rate. Software developers also require the database to be properly maintained by planning them and designing their way of existence and administering them after deployment. In this chapter, you will learn about how these three terms proved useful in database management system.

Database System Development Life Cycle

As a database system is a primary element of the larger organization-wide information system, the database system development life cycle is inherently connected with the life cycle of the information system. The stages of the database system development lifecycle are shown in the figure below:

Database System Development Life Cycle

What is Database Planning in DBMS?

It is the management activities that permit the stages of the database system development life cycle to be realized as efficiently and effectively as possible.

Database planning must be integrated with the overall IS strategy of the organization.

There are three main issues involved in formulating an IS strategies which are:

  • Identification of enterprise plans and goals with the subsequent purpose of information systems requirements
  • Evaluation of current information systems to find out existing strengths and weaknesses
  • Appraisal of IT opportunities that might yield aggressive advantage

An important first step in database planning is to define the mission statement for the database system. The mission statement describes the major aims of the database system. Those driving the database project within the organization that normally define the mission statement. A mission statement helps to simplify the purpose of the database system and provide a clearer path towards the efficient and effective creation of the required database system.

Database Design

This is the process of creating a design that will support the enterprise's mission statement and mission objectives for the required database system. Two main approaches to the design of a database are followed. These are:

  • bottom-up and
  • top-down

The bottom-up approach starts at the fundamental level of attributes (i.e., properties of entities and relationships) which through analysis of the associations between attributes are clustered into relations that signifies types of entities and relationships between entities.

A more appropriate strategy for the design of complex databases is to use the top-down approach which starts with the development of data models that holds few high-level entities and relationships and then applies consecutive top-down refinements to identify lower-level entities, relationships, and the associated attributes. The top-down approach can be understood better using the concepts of the Entity-Relationship (ER) model, beginning with the identification of entities and relationships between the entities, which are of interest to the organization.

Database Administration

A DBMS normally provides various utilities for aiding database administration that includes utilities for loading data into their respective database and finally monitoring the system. The utilities allow system monitoring give information on and query execution strategy. The Database Administrator (DBA) is the one who can use this information to tune the system to give better performance result to the database, by generating additional indexes to speed up queries, by altering storage structures, or by combining or splitting tables.

The monitoring process continues throughout the life of a database system and in time may lead to the restructuring of the database for satisfying the changing requirements. These changes ultimately provide information on the likely evolution of the system and the future resources that may be needed. This, together with knowledge of the proposed new applications, enables the DBA to connect in capacity planning and to notify or alert senior staff(s) for adjusting plans consequently. If the DBMS lacks certain utilities, the DBA can either develop the required utilities in-house or purchase additional vendor tools based on the requirement.

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