sql - 如何在实体框架中执行原始 sql 查询？

Question

我正在使用带有实体框架 5 的 asp.net mvc 3。我有我的 .edmx 文件并能够使用 linq 或 SP 与我的数据库进行交互，但我想运行一些原始 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();
}

可以这样执行sql查询吗？谢谢。

Answer 1

您可以执行以下类型的查询：

1. 返回特定类型实体的实体类型的 SQL 查询。

   using (var ctx = new SchoolDBEntities())
    {
   
        var studentList = ctx.Students.SqlQuery("Select * from Student").ToList<Student>();
   
   }
   

2. 返回原始数据类型的非实体类型的 SQL 查询。

   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>();
     }
   

3. 对数据库的原始 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");
   
          }
   

你也可以参考这个

Answer 2

这已经奏效了！！

using (var ctx = new HR())
        {

            ctx.Database.ExecuteSqlCommand("insert into Employees values (9, 'Beverage')");

            ctx.SaveChanges();
        }