Entity Framework Code First Simple model not working.... : The Official Microsoft ASP.NET Forums

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Re: Entity Framework Code First Simple model not working....

Feb 01, 2013 03:34 AM|LINK

anderson7777
anderson7777

You cannot create the Relationship between the Livro and Avaliacao.

That is the Problem. You database is wrong.

Best Regards
Weera

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Re: Entity Framework Code First Simple model not working....

Feb 01, 2013 03:36 AM|LINK

why not?

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Re: Entity Framework Code First Simple model not working....

Feb 01, 2013 03:41 AM|LINK

anderson7777
anderson7777

Following is new code

using System;
using System.Collections.Generic;
using System.Data.Entity;
using Biblioteca4.Models;
using System.Data.Entity.ModelConfiguration.Conventions;
using System.ComponentModel.DataAnnotations.Schema;


namespace Biblioteca4.DAL
{
    public class BibliotecaContext : DbContext
    {
        public DbSet<Autor> Autores { get; set; }
        public DbSet<Livro> Livros { get; set; }
        public DbSet<Avaliacao> Avaliacoes { get; set; }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();

            SetupAutorEntity(modelBuilder);
            SetupLivroEntity(modelBuilder);
            SetupAliacaoEntity(modelBuilder);
        }

        private static void SetupAutorEntity(DbModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Autor>().HasKey(a => a.AutorId);
            modelBuilder.Entity<Autor>().Property(a => a.AutorId)
                .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
        }

        private static void SetupAliacaoEntity(DbModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Avaliacao>().HasKey(a => a.AvaliacaoId);
            modelBuilder.Entity<Avaliacao>().Property(a => a.AvaliacaoId)
                .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
        }

        private static void SetupLivroEntity(DbModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Livro>().HasKey(l => l.LivroId);
            modelBuilder.Entity<Livro>().Property(l => l.LivroId)
                .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);

            modelBuilder.Entity<Livro>().HasRequired(l => l.Autor).WithMany(o => o.Livros).HasForeignKey(d => d.AutorID);
        }
    }
}

Best Regards
Weera

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Re: Entity Framework Code First Simple model not working....

Feb 01, 2013 03:42 AM|LINK

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.ComponentModel.DataAnnotations;
using Biblioteca4.DAL;

namespace Biblioteca4.Models
{
    public class Autor
    {

  

        //[Key]
        public int AutorId { get; set; }

        [Required]
        [MaxLength(100)]
        public string Nome { get; set; }

        [Required]
        [Display(Name = "Data de nascimento")]
        [DisplayFormat(DataFormatString = "{0:d}", ApplyFormatInEditMode = true)]
        public DateTime Data { get; set; }

         public virtual ICollection<Livro> Livros { get; set; }

        public virtual ICollection<Avaliacao> Avaliacoes { get; set; }
    }

}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace Biblioteca4.Models
{
    public class Avaliacao
    
    
    {
        
        //[Key]
        public int AvaliacaoId{ get; set; }

        [Required]
        public string Nome { get; set; }

       
        [Required]
        [DisplayFormat(DataFormatString = "{0:d}", ApplyFormatInEditMode = true)]
        public DateTime Data { get; set; }

        [Required]
        public string text { get; set; }

        [Range(0, 5, ErrorMessage = "Nota deve estar entre 0 e 5")]
        public int Nota { get; set; }

         
        //public int  LivroId { get; set; }

       
        public int  AutorId  { get; set; } 
     
         //public virtual Livro  Livro { get; set; }

      
        public virtual Autor Autor { get; set; }

    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using Biblioteca4.DAL;

namespace Biblioteca4.Models
{
    public class Livro
    {
        
        //[Key]
        public int LivroId { get; set; }
       

        [Required(ErrorMessage = "E necessario titulo")]
        [MaxLength(100, ErrorMessage = "Titulo deve ter no maximo 100 caracteres")]
        public string Titulo { get; set; }

        [Required]
        [DisplayFormat(DataFormatString = "{0:d}", ApplyFormatInEditMode = true)]
        public DateTime Data { get; set; }


        [Required]
        [Range(1, 5000, ErrorMessage = "Valor deve ser entre 1 e 5000")]
        public int Paginas { get; set; }

  
       
        public int AutorID { get; set; }

           
        
        public virtual Autor Autor { get; set; }

        public decimal Price { get; set; }
             
        //public virtual ICollection<Avaliacao> Avaliacoes { get; set; }
    }
}

Best Regards
Weera

Reply

Re: Entity Framework Code First Simple model not working....

Feb 01, 2013 03:46 AM|LINK

SQL Server does simple counting of cascade paths and, rather than trying to work out whether any cycles actually exist, it assumes the worst and refuses to create the referential actions (CASCADE): you can and should still create the constraints without the referential actions. If you can't alter your design (or doing so would compromise things) then you should consider using triggers as a last resort.

FWIW resolving cascade paths is a complex problem. Other SQL products will simply ignore the problem and allow you to create cycles, in which case it will be a race to see which will overwrite the value last, probably to the ignorance of the designer (e.g. ACE/Jet does this). I understand some SQL products will attempt to resolve simple cases. Fact remains, SQL Server doesn't even try, plays it ultra safe by disallowing more than one path and at least it tells you so.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace Biblioteca4.Models
{
    public class Avaliacao
    
    
    {
        
        //[Key]
        public int AvaliacaoId{ get; set; }

        [Required]
        public string Nome { get; set; }

       
        [Required]
        [DisplayFormat(DataFormatString = "{0:d}", ApplyFormatInEditMode = true)]
        public DateTime Data { get; set; }

        [Required]
        public string text { get; set; }

        [Range(0, 5, ErrorMessage = "Nota deve estar entre 0 e 5")]
        public int Nota { get; set; }

         
        public int LivroId { get; set; } you can use the Independeny Navigation FK, when you query the data by using funxtion such as the Join etc
       
        public int  AutorId  { get; set; }
     
         //public virtual Livro  Livro { get; set; }

      
        public virtual Autor Autor { get; set; }

    }
}

Best Regards
Weera