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I am running EF Core on Windows and Linux and have same issue on both.

public string DbPath { get; }

string DbPath = $ "{Environment.GetFolderPath(Environment.SpecialFolder.Personal)}{Path.DirectorySeparatorChar}smart_contracts.db";

This prints the path on Linux and on Windows 10. When I try to run Add-Migration and Update-Database I get the SQLite error

Error 1: 'no such table: __EFMigrationsHistory'. error.

Code:

protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
    optionsBuilder.UseSqlite($"Data Source={DbPath}");
}

If I change it to Data Source=smart_contracts.db, it works perfectly on both platforms.

Can anyone help me get a path into the data source string?

marc_s
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Patrick
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2 Answers2

4

It seems to me that the problem is that you want to perform a migration on a database that is already structured and not generated by the Entity Framework. This would explain the lack of the migration table. To use this database you should reverse engineer the database structure. In case you do not want to change the structure either on the database side or on the application side (because, let's say you implemented the entities yourself), all you need to do is to specify the localization of the database file when configuring DbContext (as it is shown in your post) and that's it.

Here a example of Scaffolding a SQLite database:

Scaffold-DbContext "DataSource=file.sqlite3 "Microsoft.EntityFrameworkCore.Sqlite -OutputDir Models

Edit: The problem apparently stems from the fact of how you combine the path to the database file. The better practice is to use the Path.Combine() method instead of string concatenation.

Krzysztofz01
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  • Sorry I should have made clear. This is a fresh start. The error arises on Add-Migration InitialCreate. – Patrick Aug 27 '22 at 13:20
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    Now looking at the DbPath variable, I noticed how the path is joined. The use of Path.Combine is a better practice than the use of string contact. Try to migrate after refactoring this line of code or put the path as string directly into the UseSqlite() method for test purposes, to see if the error is due to path merging – Krzysztofz01 Aug 27 '22 at 13:37
  • Interesting. Path.Combine can't handle the special folder. string[] paths = {Environment.GetFolderPath(Environment.SpecialFolder.Personal), Path.DirectorySeparatorChar.ToString(), "smart_contracts.db"}; string DbPath = Path.Combine(paths); This produces DbPath = "\\smart_contracts.db" I guess that is why sqlite refuses to use it and works fine with an absolute path. Sad as I have to do different paths for Linux and Windows. Many thanks. How can I get you marked as having the correct answer? – Patrick Aug 27 '22 at 14:52
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    Just my answer above, I will make corrections to the answer informing that the problem was path combining related. – Krzysztofz01 Aug 27 '22 at 15:12
  • I received the same, somewhat deceiving, error message of the missing `__EFMigrationsHistory` table. The wrong path comment put me on the right track here. In my case it turned out I goofed-up on my "DbContext" creation, where I forgot that running a migration from the command line was not reading the connection string I configured in the `Program.Main()` method. So I implemented `IDesignTimeDbContextFactory` for running migrations from the command line, which solved it for me. For those interested what I'm talking about here refer to this post: https://stackoverflow.com/a/73673604/1816032 – gvdvenis Jan 24 '23 at 15:41
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In my case it was the debug launch profile values that I had changed while debugging from Development to Production. I had not specified the connection string setting on the production app settings file. I just changed ASPNETCORE_ENVIRONMENT from Production to Development.

Leaving this here just in case it helps.

M. Arnold
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