C# Web API INNER JOIN 和 RETURN 查询值

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我计划从数据库读取数据，然后使用内部联接 in C# WebApi控制器如下图所示。

以下查询适用于内部联接参考：

Select FirstName, LastName, Gender, Salary, E.Department_id, Department_Name 
from Employee E
INNER JOIN Department D on D.department_id = E.department_id

UPDATE

答案已通过以下代码确认通过连接数据的解决方案DTO法

    public class JoinController: ApiController
    {
    DepartmentServicesEntities DSE = new DepartmentServicesEntities();
    [Route("Api")]

        [HttpGet]
        public object JoinStatement()
        {
            using (DSE)
            {
                var result = (from e in DSE.employee join d 
                in DSE.department on e.department_id equals d.department_id 
                select new {
                FirstName = e.FirstName, 
                LastName = e.LastName, 
                Gender = e.Gender, 
                Salary = Salary, 
                Department_id = e.department_id, 
                Department_Name = d.department_name
                }).ToList();
            // TODO utilize the above result
            return result;
            }
        }
    }
}

至于加盟多表，解决方案在这里：

namespace WebApiJoinData.Controllers
{
    [RoutePrefix("Api")]
    public class JoinController : ApiController
    {
        DepartmentServicesEntities DSE = new DepartmentServicesEntities();
        [Route("Api")]

        [HttpGet]
        public object JoinStatement()
        {
            using (DSE)
            {
                var result = (from e in DSE.employees
                              join d in DSE.departments on e.department_id equals d.department_id
                              join ws in DSE.workingshifts on e.shift_id equals ws.shift_id
                              select new
                              {
                                  FirstName = e.FirstName,
                                  LastName = e.LastName,
                                  Gender = e.Gender,
                                  Salary = e.Salary,
                                  Department_id = e.department_id,
                                  Department_Name = d.department_name,
                                  Shift_id = ws.shift_id,
                                  Duration = ws.duration,
                              }).ToList();
                // TODO utilize the above result

                string json = Newtonsoft.Json.JsonConvert.SerializeObject(result, Newtonsoft.Json.Formatting.Indented);
                return result;
            }
        }
    }
}

输出结果如下所示here:

根据上面给出的模型，您应该将查询更改为：

public class JoinController: ApiController
{
DepartmentServicesEntities DSE = new DepartmentServicesEntities();
[Route("Api")]

    [HttpGet]
    public object JoinStatement()
    {
        using (DSE)
        {
            var result = (from e in DSE.employee join d 
            in DSE.department on e.department_id equals d.department_id 
            select new {
            FirstName = e.FirstName, 
            LastName = e.LastName, 
            Gender = e.Gender, 
            Salary = Salary, 
            Department_id = e.Department_id, 
            Department_Name = d.Department_Name
            }).ToList();
        // TODO utilize the above result
        }
    }
}

上面的代码只有一个问题，因为结果总是一个匿名类型目的。因此，建议使用Data Transfer Object(DTO）每当您遇到多实体连接结果以进行正确映射时。