sql - 如何在 Entity Framework 中执行原始SQL查询？

Question

我正在使用带有 Entity Framework 5的asp.net mvc3。我有.edmx文件，并能够使用linq或SP与数据库交互，但是我想运行一些原始的sql语句。我正在尝试这样的事情:

Using(var ctx=new HREntities())
{
  ctx.Database.ExecuteSqlCommand("insert into Employees values {0}, {1}",   model.EMPLOYEEID, model.EMPLOYEENAME);
  ctx.SaveChanges();
}

是否有可能以这种方式执行sql查询？谢谢。

Answer 1

您可以执行以下类型的查询:

用于查询实体类型的SQL查询，该查询返回特定类型的实体。

using (var ctx = new SchoolDBEntities())
 {

     var studentList = ctx.Students.SqlQuery("Select * from Student").ToList<Student>();

}

用于非实体类型的SQL查询，该查询返回原始数据类型。

using (var ctx = new  SchoolDBEntities())
{

var studentName = ctx.Students.SqlQuery("Select studentid, studentname 
    from Student where studentname='New Student1'").ToList();
}


 //Error
 using (var ctx = new SchoolDBEntities())
 {                
     //this will throw an exception
     var studentName = ctx.Students.SqlQuery("Select studentid as id, studentname as name 
        from Student where studentname='New Student1'").ToList();
 }

 //SQL query for non-entity types:
  using (var ctx = new SchoolDBEntities())
  {
       //Get student name of string type
      string studentName = ctx.Database.SqlQuery<string>("Select studentname 
    from Student where studentid=1").FirstOrDefault<string>();
  }

到数据库的原始SQL命令。

      using (var ctx = new SchoolDBEntities())
      {

           //Update command
           int noOfRowUpdated = ctx.Database.ExecuteSqlCommand("Update student 
        set studentname ='changed student by command' where studentid=1");
          //Insert command
         int noOfRowInserted = ctx.Database.ExecuteSqlCommand("insert into student(studentname) 
        values('New Student')");
         //Delete command
         int noOfRowDeleted = ctx.Database.ExecuteSqlCommand("delete from student 
        where studentid=1");

       }

您也可以引用 this