调试实体框架SQL语句

问题描述

这是来自我的网页主机 -

这是从我的本地服务器 -

如果您尝试获取在上下文中调用SaveChanges（）时运行的SQL，那不是那么容易。你可以看看EFTracingProvider：

或者，假设您使用SQL服务器，您可以直接访问SQL Profiler并捕获T-SQL语句（这是我的首选方法）。

I am having a weird pattern of response time when using the Entity Framework for SQL communication.

This is from my web host - http://i55.tinypic.com/263uiag.png

This is from my local server - http://i53.tinypic.com/102t4xe.png

It's the increase in response time I am worried about.I have narrowed the problem down to one single line in codeNop.Data > EfRepository.cs > public void Insert(T entity) > _entities.Add(entity);Yes I know this very specific for the NopCommerce, but the point is really that I am looking her for help on how to debug this.

Are there some events I can catch that display the SQL being executed?Or what other things can I do to find out more what is actually happening in the Entity Framework in that above command.

解决方案

For debugging EF queries, the easiest thing is to cast the query to ObjectQuery and use ToTraceString:

var query = myContext.MyTable
    .Where(r => r.Id == searchId)
    .Select(r => r);

Console.WriteLine(((ObjectQuery)query).ToTraceString());

This will show the underlying SQL for the query, and you can run the queries manually to debug why they are slow. Here is the MSDN link:

http://msdn.microsoft.com/en-us/library/system.data.objects.objectquery.totracestring.aspx

If you're trying to get the SQL which is run when you call SaveChanges() on your context, it's not as easy. You could take a look at EFTracingProvider:

http://blogs.msdn.com/b/jkowalski/archive/2009/06/11/tracing-and-caching-in-entity-framework-available-on-msdn-code-gallery.aspx

Or, assuming you use SQL Server, you can go directly to SQL Profiler and capture the T-SQL statements (this is my preferred approach).

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