Question

我正在尝试从SQL查询中检索Dataset。我正在使用Edmx进行数据访问。如果我使用一个简单的存储过程来检索dataTable，那么该函数工作正常，当我尝试检索数据集时，我无法将SQL结果转换为数据集。

这是我的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

如何在C＃中检索SQl结果中的数据集？

Answer 1

给定sql查询，将结果填充到数据集中的最简单方法是使用SqlDataAdapter类，它完成所有工作（您只需要提供查询和打开的连接，并填充数据集）。

在你的情况下，它将是：

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

实体框架返回实体而不是数据表或数据集。你可以使用ADO.net（SqlCommand，SqlAdapter，....）或者通过使用.AsEnumerable（）手动完成并将其填入新的数据表或数据集中！

如何从C＃中的SQL查询中检索数据集？

2 个答案: