设置什么 <TEntity> 在IDbSet接口中做什么？

Question

I read an article about UOW in Entity Framework , it has some code like this:

public interface IUnitOfWork
{
    IDbSet<TEntity> Set<TEntity>() where TEntity : class;
    int SaveChanges();
}

i really dont understand what does Set<TEntity>() do ?

Answer 1

All entities are stored in a context with different flags (for example DELETED, CHANGED) in front of your database. If SaveChanges will be called a synchronization with the database will be triggered. The Set contains all deleted and modified marked entities/database records inside a transaction. If the transaction commit was successful the changes in all entities contained in the set will be visible; if not a rollback will be started. It acts like a cache tracking all changes inside the target transaction. In this article a description of the UOW design pattern can be found ( http://www.codeproject.com/Articles/581487/Unit-of-Work-Design-Pattern ).