Conceptual structure design of computer room toll system database

The general process of designing a database must be known to everyone. Do not know can be very easy to find relevant information on the Internet, usually, we will be divided into 6 stages of database design. Requirements analysis stage, conceptual structure design phase, logical structure design phase, physical structure design phase, implementation stage, implementation and maintenance stage.

This time we do not talk about the theoretical knowledge of database design, mainly based on the database design of the computer room charge system as the background to explain how the conceptual structure of the database design is generated, of course, contains the most difficult requirements of database design analysis, otherwise there is no database concept structure design.

Since we have done it all over again, and from the beginning we are doing it according to the system prototype, there is no process from scratch, so we can not understand what the real demand analysis is, and will not think about how the various functions of the development system are abstracted. I will start with my own understanding of the database design of the computer room charge system.

Computer room charge system is for the staff of the machine room and management personnel use. Therefore, the user of the system will be an entity, in order to meet customer needs, but also to the user to set permissions.

The information that the system wants to manage is the information of the student itself and the data record of the student because of the machine, so the student is also an indispensable entity.

Very many people because of the three-paradigm principle, the original student information on the card information in the part of the extraction, formed a body, namely the card entity. This improves the flexibility of the database. After a student's card is lost, it is possible to delete the lost card information from the database and update the card number in the student information. However, in the actual use of the system, this design does not have much advantage. Instead, the query efficiency is reduced, as two tables are involved.

Some people say that using a view can be done, but relative to a table. That's a bit of a hassle.

We continue to analyze, the system user operation will generate work records, students in the computer room on the opportunity to generate on-machine record, the system users have the card registration, logout and recharge permissions. Therefore, the corresponding data information will be generated, so that a system execution of the basic data set, the data information needs a table to store. So the main database entity diagram can be drawn out.

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The diagram above is an extremely simple one. There may be a lot of errors, after all, without the ability to skillfully and accurately handle the abstract analysis of the development system. Of course, the above diagram does not give the properties of the individual entities, the following I use Power Designer software to draw a conceptual structure of the system, of course, this figure is not a standard CDM, the main purpose is to show you the attributes of each entity.

In short, the design of the most difficult database is the initial phase of demand analysis, may require developers and customers after a very long period of repeated discussions and exchanges, can produce the results finally, and in the course of the development may also continue to improve and intact. Of course, strictly speaking, I said here is not really a database design, because the system Blueprint and database blueprint exists, will interfere with our thinking and analysis. But this is learning. To go through this process, hand to do a database, will have a profound experience, because standing on the shore will never learn to swim.

Conceptual structure design of computer room toll system database