c# – 实体框架4.1代码优先和一对多映射问题

我有映射现有数据库的问题.

2桌(简化)

"SomeEntity"
Id int
Name nvarchar

和

"EntityProperty"
EntityId int
Name nvarchar

并且从实体到实体属性具有一对多的关系.

我如何使用EF 4.1 Code First进行映射？

Thx提前.

编辑1：

好的)这是我的代码

class Program
    {
        static void Main(string[] args)
        {
            var context = new DataContext();

            var result = context.SomeEntity.Include(p => p.EntityProperties);

            foreach (var entity in result)
            {
                Console.WriteLine(entity);
            }

        }
    }

    public class SomeEntity
    {
        public int EntityId { get; set; }
        public string Name { get; set; }
        public virtual ICollection<EntityProperty> EntityProperties { get; set; }

        public override string ToString()
        {
            return string.Format("Id: {0}, Name: {1}", EntityId, Name);
        }
    }

    public class EntityProperty
    {
        public int EntityId { get; set; }
        public string Name { get; set; }
    }

    public class DataContext : DbContext
    {
        public DbSet<SomeEntity> SomeEntity { get { return this.Set<SomeEntity>(); } }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Entity<SomeEntity>().ToTable("SomeEntity");
            modelBuilder.Entity<SomeEntity>().HasKey(k => k.EntityId);

            modelBuilder.Entity<EntityProperty>().ToTable("EntityProperty");
            modelBuilder.Entity<EntityProperty>().HasKey(k => k.EntityId);
        }
    }

在查询获取属性时使用Include时出现问题：

列名称“SomeEntity_EntityId”无效.
列名称“SomeEntity_EntityId”无效.

解决方法:

public class SomeEntity
{
    public int SomeEntityId {get;set;}
    public string Name {get;set;}
    public ICollection<EntityProperty> EntityProperties {get;set;}
}

public class EntityProperty
{
    public int EntityPropertyId {get;set;}
    public string Name {get;set;}
}

创建ICollection(在关系的“1”侧)应足以设置1：N关系.它将在EntityProperty表中创建SomeEntity_Id(或SomeEntityId)列.

编辑：顺便说一句：如果要启用延迟加载,可以将该集合设置为虚拟.

public virtual ICollection<EntityProperty> EntityProperties {get;set}

编辑：

public class SomeEntity
{
    [Key]
    public int Id {get;set;}
    public string Name {get;set;}
}

public class EntityProperty
{
    // What is PK here? Something like:
    [Key]
    public int Id {get;set;}

    // EntityId is FK
    public int EntityId {get;set;}

    // Navigation property
    [ForeignKey("EntityId")]
    public SomeEntity LinkedEntity {get;set;}

    public string Name {get;set;}
}

首先尝试这个…然后你可以再次添加ICollection,这次我没有包含它以保持简单(你还是一个查询属性..但是：context.EntityProperties.Where(x => x.EntityId == X);)

标签：c,entity-framework,entity-framework-4,ef-code-first,code-first
来源： https://codeday.me/bug/20190626/1296345.html