Tag: Entity Framework Core

Unit testing code using Entity Framework Core

https://docs.microsoft.com/en-us/ef/core/miscellaneous/testing/

I tried to use Moq to mock the DbContext and IQueryable<>, but it seems to be really complicated. It’s also not recommended by Microsoft.

For unit testing, it’s recommended to use a real database, perhaps using an in-memory database or a temporary sqlite database. Whatever the type of database you use, install the required NuGet package.

EF Core Update-Database failed with MySQL

When trying to use the code first approach of Entity Framework Core to generate database and tables using MySQL. When running Update-Database in the package console manager, it shows an error saying table __efmigrationhistory doesn’t exists.

After digging in Stackoverflow, it seems that it’s a bug with the official MySQL connector. And at the time of this writing with this version 8.0.20 and .NET Core 3.1, this bug hasn’t been fixed. The connector is supposed to create this table for migration.

https://stackoverflow.com/a/46090571/9191495

In order to solve this problem there are two solutions

-Don’t use the official connector, use Pomelo.EntityFramework.MySql

https://www.nuget.org/packages/Pomelo.EntityFrameworkCore.MySql

-Alternatively create, the table yourself

CREATE TABLE `__EFMigrationsHistory` 
( 
    `MigrationId` nvarchar(150) NOT NULL, 
    `ProductVersion` nvarchar(32) NOT NULL, 
     PRIMARY KEY (`MigrationId`) 
);

It’s a waste of time, but what can one do.