Database Design
Donald Green
What is database design?
Database design is a set of processes that facilitate the design, development, implementation, and maintenance of enterprise data management systems. A properly designed database is easy to maintain, improves data consistency, and is economical in terms of disk space. The database designer decides how the data elements are related and what data should be stored.
The main tasks of database design are the creation of logical and physical models for designing the proposed database system.
The logical model concentrates on the data requirements and data that must be stored regardless of physical considerations. It does not address how the data will be stored or where it will be physically stored.
The physical data design model involves translating the logical design of a database onto a physical medium using hardware resources and software systems such as database management systems (DBMS).
Why is database design important?
It helps produce database systems
- It meets the requirements of users
- Have high performance.
Database design is critical to a high performance database system.
Note that the genius of a database lies in its design. Data operations using SQL are relatively easy
Database Development Life Cycle
The database development life cycle consists of several phases that are performed during the development of database systems.
The steps in the development life cycle need not be followed in a religiously consistent manner.
In small database systems, the database system development life cycle is usually very simple and does not include many steps.
To fully appreciate the diagram above, let's take a look at the individual components listed in each step.
Requirements analysis
- Planning − This stage concerns the planning of the entire database development lifecycle. Takes into account the organization's information systems strategy.
- System Definition − This phase defines the scope and boundaries of the proposed database system.
Database design
- logical model. This phase is concerned with developing the database model based on the requirements. The whole project is on paper without any physical implementations or special DBMS considerations.
- Physical model - at this stage, the logical model of the database is implemented, taking into account the DBMS and physical implementation factors
Implementation
- Data Conversion and Loading − This stage is concerned with importing and converting data from the old system to the new database.
- Testing - this stage is associated with identifying errors in the newly implemented system. It checks the database against requirements specifications.
Two types of database technology
- normalization
- ER Modeling
Let's study them one by one
