如何只更新修改的值（EntityFramework 5.0）？ [英] How to update only modified values (EntityFramework 5.0)?

问题描述

我有这个实体，想要使用entityframework更新

I have this entity, want to update using entityframework

 EmployeeModel employee = new EmployeeModel
    {
        Id = 1000, //This one must 
        FirstName = modifiedValue,
        Email = modifiedValue, 
        LastName = originalValue,
        Phone = originalValue
    };

要更新的代码

_db.ObjectStateManager.ChangeObjectState(employee, EntityState.Modified);  
_db.SaveChanges();

这是一次更新的SQL语句

This is the SQL statement got once updated

Update Employee set Id=1138,FirstName='modifiedValue',Email='modifiedValue',LastName= 'OriginalValue',phone='originalValue' where Id=1138

但我期待这个

Update Employee set FirstName='modifiedValue', Email='modifiedValue' where Id=1138.

我不知道我在这里失踪了。请告诉我。

I dont know what I am missing here. Please let me know.

推荐答案

这是我得到的解决方案

 var entity = _db.CreateObjectSet<Employee>();
 entity.Detach(employee);
 entity.Attach(employee);

 foreach (string modifiedPro in employeeModel.ModifiedProperties){
  _db.ObjectStateManager.GetObjectStateEntry(employee).SetModifiedProperty(modifiedPro);}

  _db.SaveChanges();

仅在sql update语句中修改的值

Only modified values in the sql update statement

Update Employee set FirstName='modifiedValue', Email='modifiedValue' where Id=1138.

如果任何人都知道更好的答案，请张贴你的建议

If anybody knows better answer than this, Please post your suggestions

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