3.级联删除

Posted 2022-10-11 nocanstillbb

authors表是主表

books表是子表

默认情况下,当使用datacontext.dbset.remove 删除authors时,  与之相关的books也会一起删除掉.

using (var context = new BookStore())
    
    var author = context.Authors
        .FirstOrDefault();
    
    context.Authors.Remove(author);
    context.SaveChanges();

 

 

不过可以使用WillCascadeOnDelete(false)来关闭级联删除

protected override void OnModelCreating(DbModelBuilder modelBuilder)

    modelBuilder.Entity<Book>()
        .HasOptional<Author>(b => b.Author)
        .WithMany()
        .WillCascadeOnDelete(false);

这样再执行本随笔第一个代码段就不会删除与之相关的books了.