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How to Inspect the SQL Generated by Entity Framework Core using .NET Core's built in Logging

galwaycoder profile image Eamon Keane Originally published at eamonkeane.dev Updated on ・2 min read

Today I'm going to show you how to intercept and view the SQL generated by Entity Framework Core. This method takes advantage of Microsoft's built in logging for .NET core.

This is something I wish i knew about starting off. I hope it's of use to somebody else.

This method is an alternative to profiling the SQL using something like SQL Server Management Studio. This will work with an ASP.NET Core application which should cover the vast majority of use cases!

By default, .NET core outputs logs to the following locations when you call HostCreateDefaultBuilder(args) within Program.cs:

  • Console
  • Debug
  • Event Source
  • EventLog (Windows Only)

Default providers for logging is ASP.Net Core 3.1 (Microsoft Documentation)

1. Enable Sensitive Data Logging

Navigate to your startup file for your .NET Core project (Startup.cs). Now find where you've configured your application to use Entity Framework Core. This should be in the ConfigureServices method.

Alt Text

Enable sensitive data logging by calling the EnableSensitiveDataLogging method.

 services.AddDbContext<DutchContext>(
                cfg =>
                {
                    cfg.UseSqlServer(_config.GetConnectionString("DutchConnectionString")).EnableSensitiveDataLogging();
                }
                );
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Enabling Sensitive Data Logging allows you to view the parameters being passed into the SQL Queries in the logs.

2. Configure the Logging using your Configuration File

The next step is to tell your ASP.NET Core App to log Entity Framework Core commands.

For this step, go to your config file. Typically this is named 'Appsettings.json'. It's likely you configured the connection string for your application here.

This is what mine looks like:

Alt Text

Add a new line to "Logging" => "LogLevel"

 "Microsoft.EntityFrameworkCore.Database.Command": "Information"
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The logging config should now look something like this:

"Logging": {
        "LogLevel": {
            "Default": "Information",
            "Microsoft": "Warning",
            "Microsoft.EntityFrameworkCore.Database.Command": "Information"
        }
    }
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My final configuration file:

Alt Text

That's it!

You can now run your application and see the SQL generated by Entity Framework Core in any of the default providers mentioned earlier.

Here I'm using the output window in Visual Studio 2019 and showing the output from ASP.NET Core Web Server.

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If you can't see the output window just use 'Ctrl + Alt + O' to bring it up or find it in the View menu at the top of visual studio.

This article first appeared on Eamon Keane's Blog at www.eamonkeane.dev

Hope this helps someone out!

Let me know if it helps you out in the comments below

I'm also over on twitter where I tweet about software development. Call over and say hello! @eamokeane

Discussion (17)

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amsmart profile image
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Eamon Keane Author

glad it helped you!

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toastedguy2 profile image
ToastedGuy2

Thanks mate. Simple and Consice

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Eamon Keane Author

I'm glad you found it helpful!

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krasni profile image
krasni

Thank you very much, it works like a charm!

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galwaycoder profile image
Eamon Keane Author

You're very welcome

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jon001 profile image
jon001

Oh my word that is lovely. You've brightened my day, Eamon!

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galwaycoder profile image
Eamon Keane Author

Glad it helped!

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izakntun profile image
Isaac Cantún

Great tutorial!! very useful! Thank You

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galwaycoder profile image
Eamon Keane Author

welcome! Glad it helped

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vasiliyholub1 profile image
vasiliyholub1

Thanks. Work from a first time!

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galwaycoder profile image
Eamon Keane Author

great stuff! Welcome

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riccardo1993

Thx, it is what I needed!

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Offir Pe'er

This is not working for me, but I use .netcore 2.x

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galwaycoder profile image
Eamon Keane Author

hey, That might be the issue alright. Did you get it resolved in the end?