如何從C＃中的SQL查詢檢索數據集＃

Question

我試圖從SQL查詢中檢索Dataset。我正在使用Edmx進行數據訪問。如果我使用一個簡單的存儲過程來檢索dataTable，那麼該函數可以正常工作，當我試圖檢索數據集時，我無法將SQL結果轉換爲數據集。

這裏是我的SQL

--Query For Retrieving LastUpdatedDate 
select top 3 
    YP.utblYPBusinessInstanceInfoKeys.BusinessID, 
    YP.utblYPBusinessInstanceInfoKeys.BusinessName, 
    YP.utblYPBusinessInstanceInfoKeys.LastUpdatedByDate as GeneraliseDate 
from 
    YP.utblYPBusinessInstanceInfoKeys 
order by 
    GeneraliseDate desc 

--Query For Retrieving Listing by CreatedDate 
select top 3 
    YP.utblYPBusinessInstanceInfoKeys.BusinessID, 
    YP.utblYPBusinessInstanceInfoKeys.BusinessName, 
    YP.utblYPBusinessInstanceInfoKeys.CreatedByDate as GeneraliseDate 
from 
    YP.utblYPBusinessInstanceInfoKeys 
order by 
    GeneraliseDate desc 

我如何在C＃中檢索數據集在SQL結果？任何幫助肯定是讚賞。

Answer 1

給定sql查詢，將結果填充到數據集中的最簡單方法是使用SqlDataAdapter類，它完成所有工作（只需提供查詢和打開的連接以及填充數據集）。

在你情況下，將：

string queryString1 = "select top 3 YP.utblYPBusinessInstanceInfoKeys.BusinessID, 
            YP.utblYPBusinessInstanceInfoKeys.BusinessName, 
            YP.utblYPBusinessInstanceInfoKeys.LastUpdatedByDate as GeneraliseDate 
         from YP.utblYPBusinessInstanceInfoKeys 
         order by GeneraliseDate desc" 

string queryString2 = "select top 3 YP.utblYPBusinessInstanceInfoKeys.BusinessID, 
            YP.utblYPBusinessInstanceInfoKeys.BusinessName, 
            YP.utblYPBusinessInstanceInfoKeys.CreatedByDate as GeneraliseDate 
         from YP.utblYPBusinessInstanceInfoKeys 
         order by GeneraliseDate desc" 

string queryString = queryString1 + Environment.NewLine + queryString2; 


DataSet dataSet = new DataSet(); 

var connection = new SqlConnection("TODO:put connection string here"); 
connection.Open(); 
using(connection) 
{ 
    SqlDataAdapter adapter = new SqlDataAdapter(queryString, connection); 
    adapter.Fill(dataSet); 
} 

// here you go 
foreach(DataTable table in dataSet.Tables) 
{ 
    Console.WriteLine(table.Name); 
} 

Answer 2

實體框架返回實體而不是數據表或數據集。 您可以使用ADO.net（SqlCommand，SqlAdapter，...） 或通過使用.AsEnumerable（）手動執行它並將其填充到新的數據表或數據集中！