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Lesson 6 DBLC Design Stages
Objective Design Stages in the Database Life Cycle

(DBLC) Database Life Cycle

The database life cycle (DBLC) defines the stages involved for implementing a database, starting with requirements analysis and ending with monitoring and modification. Furthermore, the DBLC never ends because database monitoring, modification, and maintenance are part of the life cycle, and these activities continue long after a database has been implemented. Put simply, the DBLC encompasses the lifetime of the database. The five stages in the database life cycle are:

  1. Requirements analysis
  2. Logical design
  3. Physical design
  4. Implementation
  5. Monitoring, modification, and maintenance

The database lifecyle
1. Requirements analysis 2. Logical Design 3. Physical Design 4. Implementation 5. Monitoring and Modification

The first three stages (1. Requirements analysis 2. Logical Design 3. Physical Design) are database-design stages, which are listed below the diagram shown above.

I. Requirements analysis

Requirements Analysis is the first and most important stage in the Database Life Cycle.
It is the most labor-intensive for the database designer.
This stage involves assessing the informational needs of an organization so that a database can be designed to meet those needs.

II. Logical design

During the first part of Logical Design, a conceptual model is created based on the needs assessment performed in stage one. A conceptual model is typically an entity-relationship (ER) diagram that shows the tables, fields, and primary keys of the database, and how tables are related (linked) to one another.
The tables sketched in the ER diagram are then normalized. The normalization process resolves any problems associated with the database design, so that data can be accessed quickly and efficiently.

  1. conceptual model: A description of the structure of a database.
  2. entity-relationship (ER) diagram: A diagram used during the design phase of database development to illustrate the organization of and relationships between data during database design.
  3. normalization: The process of applying increasingly stringent rules to a relational database to correct any problems associated with poor design.

III. Physical Design

The Physical Design stage has only one purpose: to maximize database efficiency.
This means finding ways to speed up the performance of the RDBMS. Manipulating certain database design elements can speed up the two slowest operations in an RDBMS: retrieving data from and writing data to a database.

Developing Conceptual Model

In this course, you will complete the tasks associated with Requirements Analysis and the first part of Logical Design: developing a conceptual model. The next lesson provides an overview of the post-design stages of the DBLC.
Before moving on to the next lesson, click the link below to learn more about the stages in the DBLC.
DBLC Stages Description

Database Design for Mere Mortals