Migration After scaffold

[ruirodrigues1971]

Steps to reproduce

This problem happened last week, but now I making some documentation the error happened again.

using normal scaffold, for example

dotnet ef dbcontext scaffold "SERVER=localhost; DATABASE=zaccsemel; user ID=XXX; PASSWORD=XXXX; port=3306" "Pomelo.EntityFrameworkCore.MySql" --startup-project ../WebServerAPI -o Models

The issue

The generate context it appear fine

public partial class zaccsemelContext : DbContext
    {
        public zaccsemelContext()
        {
        }

        public zaccsemelContext(DbContextOptions<zaccsemelContext> options)
            : base(options)
        {
        }
...
}

When I make migration (to be used latter to create Test Database)

dotnet ef migrations add InitialMigration --startup-project ../WebServerAPI -o Models

I have this error

PM> dotnet ef migrations add InitialMigration --startup-project ../WebServerAPI -o Models
Build started...
Build succeeded.
System.InvalidOperationException: The DbContext of type 'zaccsemelContext' cannot be pooled because it does not have a public constructor accepting a single parameter of type DbContextOptions or has more than one constructor.
   at Microsoft.EntityFrameworkCore.Internal.DbContextPool`1..ctor(DbContextOptions`1 options)
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor, Boolean wrapExceptions)
   at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitRootCache(ServiceCallSite singletonCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite singletonCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.DynamicServiceProviderEngine.<>c__DisplayClass1_0.<RealizeService>b__0(ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.GetService(Type serviceType, ServiceProviderEngineScope serviceProviderEngineScope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.EntityFrameworkServiceCollectionExtensions.<>c__5`2.<AddDbContextPool>b__5_0(IServiceProvider sp)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitFactory(FactoryCallSite factoryCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSiteMain(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite callSite, RuntimeResolverContext context, ServiceProviderEngineScope serviceProviderEngine, RuntimeResolverLock lockType)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite singletonCallSite, RuntimeResolverContext context)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(ServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite callSite, ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.DynamicServiceProviderEngine.<>c__DisplayClass1_0.<RealizeService>b__0(ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.GetService(Type serviceType, ServiceProviderEngineScope serviceProviderEngineScope)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ActivatorUtilities.GetServiceOrCreateInstance(IServiceProvider provider, Type type)
   at Microsoft.EntityFrameworkCore.Design.Internal.DbContextOperations.<>c__DisplayClass13_3.<FindContextTypes>b__11()
   at Microsoft.EntityFrameworkCore.Design.Internal.DbContextOperations.CreateContext(Func`1 factory)
   at Microsoft.EntityFrameworkCore.Design.Internal.DbContextOperations.CreateContext(String contextType)
   at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.AddMigration(String name, String outputDir, String contextType, String namespace)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigrationImpl(String name, String outputDir, String contextType, String namespace)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigration.<>c__DisplayClass0_0.<.ctor>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.<>c__DisplayClass3_0`1.<Execute>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)
The DbContext of type 'zaccsemelContext' cannot be pooled because it does not have a public constructor accepting a single parameter of type DbContextOptions or has more than one constructor.

The "solution" was to delete the default constructor heheheh

and the migration worked fine...

The same problem in the update comand dotnet ef database update --startup-project ../WebServerMVC --no-build

Of course the remaining project now don't work hehehe... In the final I add again the default constructor hehehe But of course this is not a good solution.

Further technical details

MySQL version: 8.0.22 Operating system: windows 10 Pro Pomelo.EntityFrameworkCore.MySql version: 5.0.0-alpha.2 Microsoft.AspNetCore.App version: .NET 5.0 (run application), the model/context in .NET standard 2.1

[lauxjpn]

The DbContext of type 'zaccsemelContext' cannot be pooled because it does not have a public constructor accepting a single parameter of type DbContextOptions or has more than one constructor.

@ruirodrigues1971 Your context class has more than one constructor. You could remove the pooling (and just the normal AddDbContext() method) or remove the default constructor, and try again.

[ruirodrigues1971]

The DbContext of type 'zaccsemelContext' cannot be pooled because it does not have a public constructor accepting a single parameter of type DbContextOptions or has more than one constructor.

@ruirodrigues1971 Your context class has more than one constructor. You could remove the pooling (and just the normal AddDbContext() method) or remove the default constructor, and try again.

Like I said

The "solution" was to delete the default constructor

But this this solution is to allow migration and update database. After I have done this steps (migration and updates) I add again the default constructor because I need this constructor in the remaining of my application.

I know that maybe I'm not using a normal scenario [I'm new in entity framework]

Database First ---(migration ---->Code base first) --- (Update ---> Generate the Test database)

Of course if this is not solved I will clone the database (whiteout data) outside of Entity Framework using scripts.

[lauxjpn]

In case this is still an issue for you, I can think of two possible solutions out of my head:

• Implement IDesignTimeDbContextFactory<TContext> (see Design-time DbContext Creation)
• Remove the default constructor and change the remaining one like this:

public zaccsemelContext(DbContextOptions<zaccsemelContext> options = null)
    : base(options ?? new DbContextOptions<zaccsemelContext>())
{
}