Error in Entity Framework 6.0.2 using "Migration"

Question

I have a project in ASP.NET MVC 4 and I'm using Entity Framework 6.0.2 for data persistence. After creating all the entities ("Model"), using the Data Annotation, I used "Migration" to create the Pack, but after the database is not criano in SQL Server 2012, the Nuget message "Sequence contains no matching element" is displayed The "connection string" is configured, and the SQL Server 2012 is active. I used the command: ``` PM> Enable-Migrations PM>Checking if the context targets an existing database... System.InvalidOperationException: Sequence contains no matching element at System.Linq.Enumerable.Single[TSource](IEnumerable`1 source, Func`2 predicate) at System.Data.Entity.Utilities.DbProviderManifestExtensions.GetStoreTypeFromName(DbProviderManifest providerManifest, String name) at System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.PrimitivePropertyConfiguration.Configure(EdmProperty column, EntityType table, DbProviderManifest providerManifest, Boolean allo…

Accepted Answer

First thought it was bug in Visual Studio, or even in classes or references to the Entity Framework installation. The only problem was, "DOUBLE" attributes. Was using the wrong notation. ex: Instead of using:

```
        [Required(ErrorMessage = "Informe a Nota do Aluno")]
        [Column("NotaAluno", TypeName = "Decimal(3,2)")]
        [DisplayName("Nota do Aluno:*")]
        public Double dNotaAluno { get; set; }
```

Use this:

```
        [DisplayFormat(DataFormatString = "{0:n2}",
            ApplyFormatInEditMode = true,
            NullDisplayText = "Sem Nota")]
        [Range(0, 100, ErrorMessage = "A nota deverá ser entre 0 a 100.")]
        [Required(ErrorMessage = "Informe a Nota do Aluno")]
        [Column("NotaAluno", TypeName = "decimal")]
        [DisplayName("Nota do Aluno:*")]
        public decimal dNota { get; set; }
```

Small problem, lack of attention in the creation of class and respect the primitive types of SQL Server. Thanks.

Error in Entity Framework 6.0.2 using "Migration"

Solution

Problem