E-r diagram design of reconstruction of charge system in computer room

Introduction to the learning process :
the days were too busy to be designed for nearly one weeks. In this period of time, I met the difficulties, actively find Brother Siang to guide the maze, now how much is finally some to take the results of the shot. Learning Outcomes: Entity Relationship Diagram
realational Schemas

Student (Studentid,studentname,department,grade,class,type)

Card (cardid,cash,studentid,type,isusing)

Basicdata (Fixedrate,temprate,uptime,leasttime,perpartime,limitcash,thedate,thetime,username)

SystemUser (Username,psw,level,realname,creator)

Systemuserloginrecords (Username,thedate,thetime,computername)

Register (Cardid,studentid,username,thedate,thetime,initialmoney)

Recharge (Cardid,username,addmoney,thedate,thetime)

Backcard (Cardid,username,refundment,thedate,thetime)

Studentonlinerecords (Cardid,username,thedate,thetime,computername)

Studentonlinelog (Cardid,username,onlinedate,onlinetime,offlinedate,offlinetime,statu,consumetime,consumecash, ComputerName)

Systemuserworklog (Username,ondate,ontime,offdate,offtime,computername)

Daybill (Allcardcash,rechargecash,onlinecash,backcardcash,allgetcash,username,thedate)

Thinking in the study:1, register need not be associated student entity. 2. Whether the association between SystemUser and card entities is 1:n or N. 3, Systemuserlog can be considered an entity exists. Thinking Harvest:1, in the process of this design, began to like the design. Always thought the code is full of infinite fun, now can coordinate the overall, from the macro design. This process is not about the gain and loss of a city and a pool, but the pros and cons of thinking. 2, in the process of practice, constantly know what they do not know, and then to learn to master it. 3, in the IT industry mix, always need to have a certain English words. My teacher gave me the advice is: as far as possible to see English help manual, this time of the attempt, I feel that English is not very difficult, besides, there is no powerword these painting words translation. Read English manual, so easy!

E-r diagram design of reconstruction of charge system in computer room