Question

我有一个首先使用代码的MVC4应用程序。我已经创建了3个模型，我希望用它来跟踪我的客户。每个模型都指定了AssociateType（分销商或零售商）每个员工也有一个被拒绝的地区（北佛罗里达州或南佛罗里达州。

我开始创建以下模型并运行update-database以在数据库中创建表。

Associate.cs

    namespace XXX.Models
    {
        public class Associate
        {
            public int AssociateID { get; set; }
            [StringLength(50), Column(TypeName = "varchar")]
            public string AssociateName { get; set; }
            public int AddressNumber { get; set; }
            [StringLength(50), Column(TypeName = "varchar")]
            public string AddressStreet { get; set; }
            [StringLength(20), Column(TypeName = "varchar")]
            public string AddressCity { get; set; }
            [StringLength(2), Column(TypeName = "varchar")]
            public string State { get; set; }
            [StringLength(10), Column(TypeName = "varchar")]
            public string Zipcode { get; set; }
            [StringLength(16), Column(TypeName = "varchar")]
            public string MainPhoneNumber { get; set; }
            [StringLength(60), Column(TypeName = "varchar")]
            public string AssociateEmail { get; set; }
            [StringLength(80), Column(TypeName = "varchar")]
            public string AssociateWebsite { get; set; }

            //See Corresponding Navigation Properties
            [Display(Name = "Region")]
            public int RegionID { get; set; }
            [Display(Name = "AssociateType")]
            public int AssociateTypeID { get; set; }

            [StringLength(35), Column(TypeName = "varchar")]
            public string ContactFirstName { get; set; }
            [StringLength(35), Column(TypeName = "varchar")]
            public string ContactLastName { get; set; }
            [StringLength(16), Column(TypeName = "varchar")]
            public string ContactPhoneNumber { get; set; }
            [StringLength(60), Column(TypeName = "varchar")]
            public string ContactEmail { get; set; }

            public virtual Region Region { get; set; }
            public virtual AssociateType AssociateType { get; set; }
        }

AssociateType.cs

    namespace XXX.Models
    {
        public class AssociateType
        {
            [ForeignKey("Associate")]
            public int AssociateTypeID { get; set; }
            [StringLength(50), Column(TypeName = "varchar")]
            public string AssociateTypeName { get; set; }

            public virtual Associate Associate { get; set; }
        }
    }

'Region.cs'

    namespace XXX.Models
    {
        public class Region
        {
            public int RegionID { get; set; }
            [StringLength(20), Column(TypeName = "varchar")]
            public string RegionName { get; set; }
            [Column(TypeName = "varchar(Max)")]
            public string RegionDescription { get; set; }

            public virtual Associate Associate { get; set; }
        }
    }

的DbContext

    namespace XXX.Models
    {
        public class XXXDb : DbContext
        {
            public XXXDb(): base("name=DefaultConnection")
            { 

            }
            public DbSet<Associate> Associates { get; set; }
            public DbSet<AssociateType> AssociateType { get; set; }
            public DbSet<Ingredient> Ingredients { get; set; }
            public DbSet<Region> Regions { get; set; }
            public DbSet<UserProfile> UserProfiles { get; set; }


            protected override void OnModelCreating(DbModelBuilder modelBuilder)
            {
            modelBuilder.Entity<Associate>().HasKey(a => a.AssociateID);
            modelBuilder.Entity<Associate>().Property(a => a.AssociateID)
                        .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
            modelBuilder.Entity<Associate>().HasRequired(at => at.AssociateType)
                        .WithRequiredDependent();
            modelBuilder.Entity<Associate>().HasRequired(r => r.Region)
                        .WithRequiredDependent();

            modelBuilder.Entity<AssociateType>().HasKey(at => at.AssociateTypeID);
            modelBuilder.Entity<AssociateType>().Property(at => at.AssociateTypeID)
                        .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);

            modelBuilder.Entity<Region>().HasKey(r => r.RegionID);
            modelBuilder.Entity<Region>().Property(r => r.RegionID)
                        .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
            }
        }
    }

我的桌子没有被创建，IDENTITY SPECIFICATION（Is Identity）被设置为Yes .....为什么？因此，我无法向表中添加任何数据，或者出现错误：

Cannot insert the value NULL into column 'RegionID', table 'XXXDb.dbo.Regions'; column does not allow nulls. INSERT FAILS.

我的目标是填充Region＆amp; AssociateType表只有几行项目。

地区:(北佛罗里达州和佛罗里达州南部） AssociateTypes（分销商和零售商）

这样当我在CRUD操作期间添加一个Associate时，我会有两个下拉列表，其中包含AssociateType和（N或S Florida）的选项（Distributors＆amp; Retailers）。

非常感谢任何帮助。我真的对MVC感到沮丧。我已经做了很多，但开始气馁。

Answer 1

我做了一些测试，这是在我的机器上运行的解决方案我只保留了你的对象的导航属性。

public class Associate
{
    public int AssociateID { get; set; }

    public int RegionID { get; set; }
    public virtual Region Region { get; set; }
    public int AssociateTypeID { get; set; }
    public virtual AssociateType AssociateType { get; set; }
}

public class Region
{
    public int RegionID { get; set; }
    [StringLength(50), Column(TypeName = "varchar")]
    public string IngredientNameEn { get; set; }
    [Column(TypeName = "varchar(Max)")]
    public string IngredientNameEs { get; set; }

    public virtual List<Associate> Associates { get; set; }
}

public class AssociateType
{
    public int AssociateTypeID { get; set; }
    [StringLength(50), Column(TypeName = "varchar")]
    public string AssociateTypeName { get; set; }

    public virtual List<Associate> Associates { get; set; }
}

然后在OnModelCreating中你必须添加以下两个命令，这应该生成你想要的数据库

modelBuilder.Entity<Region>().HasMany(a => a.Associates)
            .WithRequired(r => r.Region).HasForeignKey(r => r.RegionID);
modelBuilder.Entity<AssociateType>().HasMany(a => a.Associates)
            .WithRequired(r => r.AssociateType).HasForeignKey(r => r.AssociateTypeID);

在类构造函数中，您可以添加此代码

 public XXXDb(): base("name=DefaultConnection")
 { 
     Database.SetInitializer(new DropCreateDatabaseIfModelChanges<XXXDb>());
     Database.Initialize(force: true);
 }

Fluent API不在SQL Server中创建标识规范（Is Identity）

1 个答案: