EntityFrameworkCore5知识点简要 - 删除数据

软删除： soft delete ,  标记为删除

硬删除:   hard delete，  从表里删除

DeleteBehavior:

Cascade Delete: 级联删除  默认

modelBuilder.Entity<Person>(entity =>
{
    entity.HasMany(x => x.Addresses)
    .WithOne(x => x.Person)
    .OnDelete(DeleteBehavior.Cascade);
});

上面代码也定义了一对多的关系

Client Set Null: 设为null

modelBuilder.Entity<Person>().HasMany(x => x.Addresses)
   .WithOne(x => x.Person)
   .HasForeignKey(x=>x.PersonId)
   .OnDelete(DeleteBehavior.ClientSetNull);

实现上面操作，需指定外键字段为 可空类型  ？

public int? PersonId { get; set; }

Set Null: 设为null

同上，但是不用我们设置为null

限制删除  Restrict Delete

modelBuilder.Entity<Person>(entity =>
{
    entity.HasMany(x => x.Addresses)
    .WithOne(x => x.Person)
    .HasForeignKey(x => x.PersonId)
    .OnDelete(DeleteBehavior.Restrict);
});