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At first I wanted to use EF Core code-first to generate my model in a PostgreSQL database. This failed because I got an exception:

No mapping to a relational type can be found for property 'Webservice.Models.Db.Order.High' with the CLR type 'bool'

So I changed my model and removed the bool but I still get the same exception. I could not find a solution for this problem.

This is my old model class:

public class Order : IEquatable<Order>, ICloneable
{
        public long Id { get; set; }
        public long? DeviceId { get; set; }

        [Required]
        [DataType(DataType.Text)]
        public Device Device { get; set; }

        public long? OriginOrderId { get; set; }

        [Required]
        [DataType(DataType.Date)]
        public DateTime RoutineStart { get; set; }

        [Required]
        [EnumDataType(typeof(Routine))]
        public Routine Routine { get; set; }

        [Required]
        [DataType(DataType.Text)]
        public int Pin { get; set; }

        [Required]
        public bool High { get; set; }


        [Required]
        [DataType(DataType.Text)]
        public int TimeInMilliseconds { get; set; }
        public string Description { get; set; }

        [NotMapped]
        public bool Ready { get; set; }

        public OrderState State { get; set; } = OrderState.Idle;
}

I started with add-migration init which resulted in this Exception:

Microsoft.EntityFrameworkCore.Infrastructure[10403]
Entity Framework Core 3.0.0 initialized 'ApplicationDbContext' using provider 'Npgsql.EntityFrameworkCore.PostgreSQL' with options: None System.InvalidOperationException: No mapping to a relational type can be found for property 'Webservice.Models.Db.Order.High' with the CLR type 'bool'.

at Microsoft.EntityFrameworkCore.Storage.RelationalTypeMappingSourceExtensions.GetMapping(IRelationalTypeMappingSource typeMappingSource, IProperty property)
at Microsoft.EntityFrameworkCore.Migrations.Internal.MigrationsModelDiffer.Add(IProperty target, DiffContext diffContext, Boolean inline)+MoveNext()
at Microsoft.EntityFrameworkCore.Migrations.Internal.MigrationsModelDiffer.DiffCollection[T](IEnumerable1 sources, IEnumerable1 targets, DiffContext diffContext, Func4 diff, Func3 add, Func3 remove, Func4[] predicates)+MoveNext()
at System.Linq.Enumerable.ConcatIterator1.MoveNext() at Microsoft.EntityFrameworkCore.Migrations.Internal.MigrationsModelDiffer.Diff(TableMapping source, TableMapping target, DiffContext diffContext)+MoveNext() at Microsoft.EntityFrameworkCore.Migrations.Internal.MigrationsModelDiffer.DiffCollection[T](IEnumerable1 sources, IEnumerable1 targets, DiffContext diffContext, Func4 diff, Func3 add, Func3 remove, Func4[] predicates)+MoveNext() at System.Linq.Enumerable.ConcatIterator1.MoveNext()
at Microsoft.EntityFrameworkCore.Migrations.Internal.MigrationsModelDiffer.Sort(IEnumerable1 operations, DiffContext diffContext) at Microsoft.EntityFrameworkCore.Migrations.Internal.MigrationsModelDiffer.GetDifferences(IModel source, IModel target) at Microsoft.EntityFrameworkCore.Migrations.Design.MigrationsScaffolder.ScaffoldMigration(String migrationName, String rootNamespace, String subNamespace, String language) at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.AddMigration(String name, String outputDir, String contextType) at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigrationImpl(String name, String outputDir, String contextType) at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigration.<>c__DisplayClass0_0.<.ctor>b__0() at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.<>c__DisplayClass3_01.b__0()
at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)
No mapping to a relational type can be found for property 'Webservice.Models.Db.Order.High' with the CLR type 'bool'.

Then I updated my Model:

public enum PinState
{
    Low,
    High
}

public class Order : IEquatable<Order>, ICloneable
{
        public long Id { get; set; }
        public long? DeviceId { get; set; }

        [Required]
        [DataType(DataType.Text)]
        public Device Device { get; set; }

        public long? OriginOrderId { get; set; }

        [Required]
        [DataType(DataType.Date)]
        public DateTime RoutineStart { get; set; }

        [Required]
        [EnumDataType(typeof(Routine))]
        public Routine Routine { get; set; }

        [Required]
        [DataType(DataType.Text)]
        public int Pin { get; set; }

        [Required]
        public PinState PinState { get; set; }

        [Required]
        [DataType(DataType.Text)]
        public int TimeInMilliseconds { get; set; }
        public string Description { get; set; }

        [NotMapped]
        public bool Ready { get; set; }

        public OrderState State { get; set; } = OrderState.Idle;
}

Then I tried add-migration inittest which resulted in exact the same exception.

My context runs as a scoped service:

services.AddDbContext<ApplicationDbContext>(options =>
                  options.UseNpgsql(Configuration.GetConnectionString("postgres")), ServiceLifetime.Scoped);

On the database side migration history is empty.

I would really appreciate if someone could explain me why this exception occurs.

Answers

I had this problem, when at first I had migrations which had been done for Sql Server database, and then I tried to add new migration for PostgreSQL

So, solution for me was to completely delete all migrations and recreate them all for PostgreSQL.