如何在实体框架中更新具有父级的子级

// 更新父级实体
var parentEntity = dbContext.ParentEntities.Find(parentId);
if (parentEntity == null)
{
    parentEntity = new ParentEntity { Id = parentId, Name = "Parent Entity" };
    dbContext.ParentEntities.Add(parentEntity);
}

// 更新子级实体
var childEntity = dbContext.ChildEntities.Find(childId);
if (childEntity == null)
{
    childEntity = new ChildEntity { Id = childId, Name = "Child Entity", ParentId = parentId };
    dbContext.ChildEntities.Add(childEntity);
}
else
{
    childEntity.ParentId = parentId;
}

// 保存更改
dbContext.SaveChanges();