A localized Review:
1. The change is expected to expectations: connect to the database code, the code Dao layer, front page design code, etc. be written separately, to maximize the impact of changes to a minimum
2. maintain semantic consistency
Reduce dependency module, no or little use inheritance, and more excuses to restrict the use of special modifications related services
3. Pan-module
Database connection statement
4. limited to select parameters
The software system is limited to the specific operating system, avoid changing: as the default application in the Apple store in Andrews can not download
Second, to prevent a chain reaction
1. Information Hiding
Database code module isolation, without affecting the other modules
2. Maintenance of existing interfaces
More use of specific interface to implement corresponding work: official website as teaching system, teachers and students call system interface is inconsistent
3. restrict communication path
4. Use arbiter
Using data stored in an external database
Third, late binding time
1. Registration runtime
In the use of the vast majority of the site, we have joined the operation to be a key indication registered users
2. Profiles
When start setting parameters