与EF4 Code First相同的表如何做到很多 [英] how to do many to many with the same table with EF4 Code First

问题描述

我有这个架构：

create table Person
(
id int identity primary key,
name nvarchar(30)
)

create table PersonPersons
(
PersonId references Person(id),
ChildPersonId references Person(id)
)

如何使用EF4创建类映射他们的代码第一个CTP5？ / p>

how to create the classes to map them using EF4 Code First CTP5 ?

推荐答案

对于POCO ...

For the POCO...

class Person
{
    public Guid PersonId { get; set; }
    public virtual Person Parent { get; set; }
    public virtual ICollection<Person> Children { get; set; }
}

...在DbContext ...中设置映射...

...set up the mapping in the DbContext...

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Person>()
        .HasOptional(entity => entity.Parent)
            .WithMany(parent => parent.Children)
            .HasForeignKey(parent => parent.PersonId);
}

...将给你一个默认的实现。如果您需要明确重命名表（并且需要多对多关系），请添加这样的内容...

...will give you a default implementation. If you need to rename the table explicitly (and want a many-to-many relationship), add in something like this...

class Person
{
    public Guid PersonId { get; set; }
    public virtual ICollection<Person> Parent { get; set; }
    public virtual ICollection<Person> Children { get; set; }
}

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    ConfigureProducts(modelBuilder);
    ConfigureMembership(modelBuilder);

    modelBuilder.Entity<Person>()
        .HasMany(entity => entity.Children)
        .WithMany(child => child.Parent)
        .Map(map =>
        {
            map.ToTable("PersonPersons");
            map.MapLeftKey(left => left.PersonId, "PersonId"); 
            map.MapRightKey(right => right.PersonId, "ChildPersonId");
            // For EF5, comment the two above lines and uncomment the two below lines.
            // map.MapLeftKey("PersonId");
            // map.MapRightKey("ChildPersonId");
        }); 
}

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