Database operation 56 design database (railway ticketing system)
1. Grading standard
Two. The result of evaluation
Three. A summary of this assignment
In the course of this evaluation, we have designed our own database and compiled corresponding code, which is very serious.
The advantages (Fluttering):
In design, everyone consciously uses the Chen method or the crow’s foot method to draw a E-R (Entity Relationship Diagram) diagram, an entity connection diagram, and an orderly and rigorous representation of the relationships among the entities, as well as the genus in the entity.In addition, we can also follow the database paradigm in order to optimize the database and minimize redundancy.
In syntax, the code is provided.Although there are minor mistakes, most code can correspond to entities.
Problems and deficiencies:
The main problem in design is the problem of the third paradigm, such as the stop time like a train in the stop station. It is suggested that people do not appear in the table because the stop time can be calculated with the arrival time and the departure time, although the station time seat field appears in the table and is correct, but to optimize the structure of the database,In order to improve storage efficiency, it is necessary to follow the third paradigm; in addition, for a train stop, a train may have more than one stop, so it is better to use the train stop information separately as an entity without violating the first paradigm (no repeating column).
Most of the problems (small mistakes) appear in grammar, when writing code, symbols must be written with half corners, quotes, and parentheses are particularly attentive; in addition, the main key is unique and cannot insert duplicate keys into the table, otherwise it violates the uniqueness of the primary key. In addition, it should be noted that the code needs to correspond with the entity.There must be no corresponding relationship between the designed database and the code.
You can modify your own database according to your own design and code problems, come on!