实体框架核心5:配置多对多关系，如何指定外键名称

Question

我有一个现有的SQL Server数据库，具有多对多关系Books&lt-&gt；通过联接表Publications:实现的Authors

CREATE TABLE [dbo].[Books]
(
[BookId] INT IDENTITY,
[Title] NVARCHAR(160) NOT NULL,
...
)
CREATE TABLE [dbo].[Authors]
(
[AuthorId] INT IDENTITY,
...
)
CREATE TABLE [dbo].[Publications]
(
[BookId] INT NOT NULL,
[AuthorId] INT NOT NULL,
CONSTRAINT [PK_Publication] PRIMARY KEY ([BookId], [AuthorId])
)

我需要在实体框架核心5中配置多对多关系。

对于EF 6，它相当简单：

protected override void OnModelCreating(DbModelBuilder mb)
{
mb.Entity<Author>() // an Author
.HasMany(a => a.Books) // has many Books
.WithMany(b => b.Authors) // with many Authors
.Map(mc =>
{
mc.ToTable("Publications"); // Join table: Publications
mc.MapLeftKey("AuthorId"); // FK Author: AuthorId
mc.MapRightKey("BookId"); // FK Book : BookId
});
}

但我对实体框架核心5有问题：

protected override void OnModelCreating(ModelBuilder mb)
{
mb.Entity<Author>() // an Author
.HasMany(a => a.Books) // has many Books
.WithMany(b => b.Authors) // with many Authors
.UsingEntity(j => j.ToTable("Publications")); // join table: Publications
// how to define foreign key columns?
}

我不知道如何映射外键列。EF核心5使用模式CCD_ 4和CCD_。

如何更改此命名约定？

谢谢

Answer 1

如果多对多表在C#代码中不相关，您可以尝试这样做：

public class Author
{
public int AuthorId { get; set; }
public ICollection<Book> Books { get; set; }
}
public class Book
{
public int BookId { get; set; }
public ICollection<Author> Authors { get; set; }
}
public class Db : DbContext
{
protected override void OnModelCreating(ModelBuilder mb)
{
mb.Entity<Author>() // an Author
.HasMany(a => a.Books) // has many Books
.WithMany(b => b.Authors) // with many Authors
.UsingEntity<Dictionary<string, object>>("Publications",
x => x.HasOne<Book>().WithMany().HasForeignKey(nameof(Book.BookId)),
y => y.HasOne<Author>().WithMany().HasForeignKey(nameof(Author.AuthorId)),
z => z.ToTable("Publications"));
}
}