What are the objectives of database design

Only small organizations can summarize information in one integrated database. Usually an administrator or a group of people is almost unable to cover and satisfy all information requirements coming from employees of the organization. That is why in large organizations, information systems consist of dozens of databases, which are often distributed between several conjugate personal computers in different divisions.

Some databases can contain all the information required to solve one or a set of applications, such databases are called application databases. If it contains information about a particular domain, then it will be referred to as the subject domain. It is difficult to overestimate the usefulness of object databases, as they allow you to supplement the information system without overwriting any already created applications.

What is the design of databases?

Speaking about the information system as a whole, it is necessary to reveal important questions. If you base the design of databases on current applications and those that are only foreseen, then the creation of an information system with a high degree of efficiency can be significantly accelerated. In this case, a highly effective means such a system, the structure of which will take into account the most common ways of access to information. It is the application design of databases that now attracts a growing number of developers. As the number of applications in such information systems increases, the number of application databases is rapidly growing, which causes a sharp increase in data duplication and an increase in the cost of their subsequent maintenance.

It turns out that each of the above approaches to design affects the design results in different directions. The desire to obtain flexibility and efficiency at the same time led to the fact that the logical design of databases is carried out using a methodology that applies applied and subject approaches at once. The subject approach is generally used to construct the original data structure, and the applied approach is used to improve it, focused on improving the efficiency of information processing.

Designing databases is only part of the work aimed at creating an information system. When it comes to the formation of an integrated information system, then it is necessary to identify the requirements for it specific users. The data collection operation starts with the fact that the essence of processes and organization is being studied. All entities after this necessarily group by some kind of similarity, as well as the number of links that arise between them. Those entities that have the greatest similarity or maximum frequency of associative connections are usually combined into subject databases.

The main goal of database design is to reduce the redundancy of the data being saved, that is, to save the amount of memory that is used, to reduce the cost of multiple updates of redundant copies, and to eliminate the potential for inconsistencies associated with storing information about a single object in different places.

Stages of database design

The design procedure has features at each of the stages and stages of design. There are a number of works related to the pre-project stage, after which it is possible to form a feasibility study and directly a technical task. After that, they pass to the stage of technical design, which is connected with the preparation of a refined model, logical and physical design, as well as the design and presentation of data for applications. The last is considered the stage of working design, the result of which is to obtain a working database, the system itself and related documentation.