Laboratory equipment borrowed applet database design experience
I. Project Description
Project name our project team developed a project for the campus borrowed equipment, the system is mainly to borrow campus laboratory equipment to facilitate teachers and students online, but also easy to manage device administrator line equipment. In real life, storage and management of laboratory equipment is the responsibility of the administrator of storage space, teachers and students can not know whether the state and in need within their campus facilities and other equipment, procedures and other borrowing will be relatively trouble . The information in this system will be integrated laboratory equipment online, user-based applet on the micro-channel view will borrow, easy to operate, the procedure is simple, for administrators may be concerned about the line situation and its equipment management.
Second, the design process
On database design, our group is designed by one person, and then put our heads back and forth to modify the 5,6 times, the following is the general process we designed the database:
1, the first point first, before the database design needs to figure out, it is important, if the demand for the software to be designed not understand, then designed the database is absolutely wrong, after the clear demand, it is necessary our analysis of this product to its users / roles which.
2. After determining entity, we need to determine what attributes of each entity, at this stage do not need to think entirely clear, probably came up with it.
3, after determining the good properties, we have to consider the relationship between entities is one to one or one to many or many to many relationship is stored in a field or another entity table a new table, this process is very long and complex, requiring repeated scrutiny.
4, repeatedly revised, thinking what to do to be able to take into account the structure of the database, integrity, redundancy, including whether the database developers call easy, but after determining the relationship between the entity we'll turn to consider each field is reasonable is there anything missing field, where best practice is against the demand list, think about this process, the database should be some changes.
5. After doing the above things, the database should be repeated testing, the first is whether the three paradigms, then this design is reasonable (if you have special needs, contrary to the three major paradigms is also acceptable, as long as reasonable).
Third, the design ideas
In designing the database, we have a lot of harvest and experience:
1, created on the table
About creating part of the table, including field names, data types and primary key design, you must first clear the table column's data type is char, varchar, int, date type, and so on, there are a few characters in length. And whether its value can be empty, which is to be considered. In this process needs to be noted that the table column names are not repeated, it is unique - nature. Set Primary Key relatively easier, my greatest experience in the analysis for each column of the table data type must be careful careful, it will be very easy to make mistakes.
2, ER FIG.
ER is the key point of the whole database design, ER diagram design error if it can not be the next design, and therefore require special careful when designing the ER diagram. ER model can easily simulate static process research object. That entity ER - Contact, ER is provided a method represented in FIG visual entity type, attributes and links. FIG ER painting process, it must be clearly recognizable entities, attributes and links, out of the box corresponding to rectangular, elliptical and diamond shaped. Database design behind this picture shows the painting to lay the foundation, through this database design, I learned a lot of knowledge, theory and practical application.
3, table diagram
Table construction diagram is also relatively easy and requires only a definite relationship between the tables, the table of contents with the same column are connected with a line. When you create a table diagram, the teacher talked about the content together, it is more relaxed. Through this design team, division of labor, I learned a lot of things can not be learned in books, feel the increased knowledge of the database, after all, he personally designed a database, is no longer a theory on the books, empty talk, still feel rewarding.
Fourth, test summary
The project design is a process for us to try and innovation, can be said to be a challenging process. While learning the database so long, but we still lack experience. Now we use the knowledge he learned in the design and production of a library management system, which itself is a process of converting knowledge into a productive, so we are very excited to have invested a high degree of enthusiasm and effort different.
In the specific design and implementation, we see and feel the process of a management system from scratch, the specific design steps, ideas, methods, techniques have a better understanding, and feel deeply. The curriculum designed to deepen our understanding of design-related knowledge as well as related functions MySQL database system. For example, in the establishment of basic tables, views, indexes, stored procedures, triggers, etc., more familiar than previously, and solve the problems of the process learned a lot of new knowledge.
We basically follow a disciplined approach and steps in the design of the first to investigate the existing system, and access to such information, to finalize the design, and then design and production, the implementation process, we deeply recognize that seriously implement the management system the importance of software standards, because we do not understand management system software-related standards and norms, the lack of operating guidelines for behavior, so in the design relatively more stiff, and twice failed to master a good grasp of these aspects through this we should strengthen understanding.
During the course design, we are assigned in groups to borrow to complete the campus lab equipment design and production of the project, so the division of labor and coordination within the group is very important, we can avoid weaknesses in the division of labor, and a director, so may well improve everyone's enthusiasm, and sense of cooperation, and effectively shorten the development time, but we are doing in this area is not enough, the lack of personnel management and communication, resulting in waste of human resources, can be said shortcomings and urgent the need to think and improvements, this must be indicated. It will be very important in future work and learning.