MySQL with EF Core 9 in ABP: Avoiding Translation Issues

#abp #abpframework #mysql #entityframework

Entity Framework Core 9 introduces several improvements, but if you are using MySQL with EF Core 9 (and using the Pomelo.EntityFrameworkCore.MySql), you need to be aware of a critical issue related to query translation.

The Problem

ABP Framework's MySQL provider (Volo.Abp.EntityFrameworkCore.MySQL) relies on Pomelo.EntityFrameworkCore.MySql NuGet package. However, as of now, the stable 9.0.0 version of this package has not been released. (You can follow the upgrade status from https://github.com/PomeloFoundation/Pomelo.EntityFrameworkCore.MySql/issues/1841, if you want).

When using EF Core 9 with MySQL in ABP-based projects, you may encounter SQL translation issues. One of the key problems is that certain queries involving parameterized collections fail to translate correctly.

The Solution

To workaround this issue, you must explicitly enable the TranslateParameterizedCollectionsToConstants() option in your EF Core configuration. Without this setting, the provider may not correctly translate certain SQL commands.

How to Apply the Fix

Open the module class of the *.EntityFrameworkCore project and configure the AbpDbContextOptions as follows:

//...

public class MyProjectEntityFrameworkCoreModule : AbpModule
{
    public override void ConfigureServices(ServiceConfigurationContext context)
    {

        //...

        Configure<AbpDbContextOptions>(options =>
        {
            options.UseMySQL(builder =>
            {
                //add the following line 👇
                builder.TranslateParameterizedCollectionsToConstants();
            });
        });

    }
}

Using the TranslateParameterizedCollectionsToConstants option ensures that parameterized collections are translated into constants, preventing SQL translation errors.

Future Updates

The good news is that once Pomelo.EntityFrameworkCore.MySql 9.0.0 is officially released, this setting will become the default. Actually, it's going to be the default starting from v9.0.0-preview.3.efcore.9.0.0 as announced here.

Until then, applying this temporary solution should allow you to use MySQL with EF Core 9 smoothly.