JSON创建中的问题。 [英] Problem in JSON Creation.

问题描述

我正在使用EF开发Web API控制器。当我像下面的代码一样使用单个表时正确获取JSON对象。

静态IEnumerable <   ProductIdAndName  >  SelectTop5ProductsIdAndName（）
 {
 NorthwindEntities northwindEntities = new NorthwindEntities（）; 
 string nativeSQLQuery = 
SELECT TOP 5 ProductID as ID，ProductName as Name+ 
FROM dbo.Products+ 
ORDER BY ProductID; 
 ObjectResult <   ProductIdAndName  >  products = 
 northwindEntities.ExecuteStoreQuery <   ProductIdAndName  > （nativeSQLQuery）; 
退货产品; 
} 

当我使用两个表时，我写了如下，因为我从多个表中获取值。

静态IEnumerable <  对象 >  SelectTop5ProductsIdAndName（）
 {
 NorthwindEntities northwindEntities = new NorthwindEntities（）; 
 string nativeSQLQuery = 
SELECT TOP 5 * FROM dbo.Products，dbo.ProductsPrice ORDER BY ProductID; 
 ObjectResult <  对象 >  products = 
 northwindEntities.ExecuteStoreQuery <   Object  > （nativeSQLQuery）; 
退货产品; 
} 

在这种情况下，我无法获得JSON，因为返回类型是对象。请给出建议来解决这个问题。

注意：我对创建视图模型不感兴趣。

解决方案

很少我注意到的事情



1.使用EF并在线编写SQL查询很糟糕。您不必显式编写SQL查询

2.以下查询可能对您有用，但这不是一个好习惯。假如你真的想要使用多个表的sql查询，用户内/外连接

 SELECT TOP 5 * FROM dbo.Products，dbo.ProductsPrice ORDER BY ProductID 

来到解决方案。构建一个视图模型或类来保存两个表的结果。您应该获取并返回视图模型。



如果您有任何疑问，请告诉我。



谢谢，

I am working on Web API controllers with EF. When i use a single table like following code am getting the JSON object correctly.

static IEnumerable<ProductIdAndName> SelectTop5ProductsIdAndName()
  {
    NorthwindEntities northwindEntities = new NorthwindEntities();
    string nativeSQLQuery =
      "SELECT TOP 5 ProductID as ID, ProductName as Name " +
      "FROM dbo.Products " +
      "ORDER BY ProductID";
    ObjectResult<ProductIdAndName> products =
      northwindEntities.ExecuteStoreQuery<ProductIdAndName>(nativeSQLQuery);
    return products;
  }

When i use two tables i wrote like following because i am getting values from multiple tables.

static IEnumerable<Object> SelectTop5ProductsIdAndName()
  {
    NorthwindEntities northwindEntities = new NorthwindEntities();
    string nativeSQLQuery =
      "SELECT TOP 5 * FROM dbo.Products, dbo.ProductsPrice ORDER BY ProductID";
    ObjectResult<Object> products =
      northwindEntities.ExecuteStoreQuery<Object>(nativeSQLQuery);
    return products;
  }

In this case am not able to get the JSON, as the return type is of object. Please give suggestios to solve this.
Note: I am not interested in creating viewmodels.

解决方案

Few things I noticed

1. Using EF and writing a SQL query inline is bad. You don't have to explicitly write sql queries
2. The following query might work for you but it's not a good practice. Say if you really want to use sql queries with multiple tables, user inner/outer joins

SELECT TOP 5 * FROM dbo.Products, dbo.ProductsPrice ORDER BY ProductID

Coming to the solution. Build a viewmodel or a class to hold the results of both tables. You should fetch and return the viewmodel.

Let me know if you have any doubts.

Thanks,

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