在 Linq To SQL 中使用 XQuery? [英] Using XQuery in Linq To SQL?

问题描述

假设我有一个包含 XML 类型数据列的表.在 SQL 中，我可以执行以下语句:

Let's say I have a table that has a column of XML type data. Within SQL, I can execute the following statement:

select   top 10  *,
         Content.value('(/root/item/value)[1]', 'float') as Value
from     xmltabletest
where    Content.value('(/root/item/MessageType)[1]', 'int') = 1

结果集只包含符合条件的记录，它从 XML 中提取一个值到一个名为值"的列中.很好很简单.

The result set contains only the records matching the criteria, and it extracts a value from the XML into a column called 'Value'. Nice and simple.

Linq To SQL 能达到同样的效果吗?

Can the same thing be achieved with Linq To SQL?

我想让 SQL 完成繁重的工作，只返回符合我的条件的数据，而不必选择、传输和处理潜在的大量数据.据我所知，目前这是不可能的，但我想我应该问一下.

I'd like to get SQL to do the heavy lifting and only return data matching my criteria rather than having to select, transfer, and then process a potentially massive chunk of data. As far as I can tell this isn't possible at the moment, but I thought I should ask.

(如果有帮助，环境是 .NET 3.5、VS2008、SQL Server 2005)

(The environment is .NET 3.5, VS2008, SQL Server 2005 if that helps)

推荐答案

我不确定这是否已经过时，但根据 Scott Guthrie XML 数据类型是:

I'm not exactly sure if this is out of date now, but according to Scott Guthrie XML datatypes are:

在 LINQ to SQL 中表示为字符串实体.您可以使用 XLINQ 来查询在 LINQ 中的 XML 列上SQL 实体 - 但这个查询会发生在你的中间层(在ASP.NET).你不能执行远程针对数据库和过滤器的 XQuery返回的结果基于首次发布.

represented as strings in LINQ to SQL Entities. You could use XLINQ to query on an XML column within your LINQ to SQL entitiy - but this querying would happen in your middle-tier (within ASP.NET). You can't execute a remote XQuery against the database and filter returned results based on that in the first release.

所以在回答你的问题时，我会说不".

So in answer to your question, I'd say "no."

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