Castle ActiveRecord学习实践(7)级联

本章来看看Castle ActiveRecord中的级联(cascade)操作

还是以post和comment为例

post.cs 修改为

   1:  [ActiveRecord("Posts")]

   2:  public class Post : ActiveRecordBase<Post>

   3:  {

   4:      [PrimaryKey("PostId")]

   5:      public int Id { get; set; }

6:

   7:      [Property]

   8:      public string Subject { get; set; }

9:

  10:      [Property]

  11:      public string Text { get; set; }

12:

  13:      [Property]

  14:      public DateTime DateAdded { get; set; }

15:

  16:      [BelongsTo("CategoryId")]

  17:      public Category Category { get; set; }

18:

  19:      [HasMany(Lazy=true,Cascade=ManyRelationCascadeEnum.AllDeleteOrphan,Inverse = true)]

  20:      public IList<Comment> Comments { get; set; }

21:

  22:      [HasAndBelongsToMany(typeof(Tag), Table = "TagPost", ColumnKey = "PostId", ColumnRef = "TagId")]

  23:      public IList<Tag> Tag { get; set; }

24:

  25:  }

HasMany特性添加Cascade

枚举属性

枚举	值
ManyRelationCascadeEnum	None	不做级联操作
	All	增删改都做级联操作
	AllDeleteOrphan	都做级联操作，并且删除孤儿数据。即删除没有对应Post的Comment对象
	SaveUpdate	在增加和更新的时候做级联操作
	Delete	在删除的时候做级联操作

1、级联添加

创建一个post ，并添加多个comment

   1:  //创建post

   2:  Post post = new Post();

   3:  post.DateAdded = DateTime.Now;

   4:  post.Subject = "castle active record 7";

   5:  post.Text = "content";

   6:  List<int> list = new List<int>();

   7:  list.Add(1);

   8:  list.Add(2);

   9:  post.Category = Category.Find(5);

  10:  post.Tag = Tag.FindAll();

  11:  using (TransactionScope tran=new TransactionScope ())

  12:  {

  13:      try

  14:      {

  15:          post.Create();

  16:          for (int i = 0; i < 10; i++)

  17:          {

  18:              //创建comment

  19:              Comment comment = new Comment();

  20:              comment.Author = "hzd" + i;

  21:              comment.DateAdded = DateTime.Now;

  22:              comment.Text = "comment" + i + " content!";

  23:              comment.Post = post;

  24:              comment.Save();

  25:          }

  26:          tran.VoteCommit();

27:

  28:      }

  29:      catch

  30:      {

  31:          tran.VoteRollBack();

  32:      }

  33:  }

2、级联更新

为已经存在的post 添加 comment

   1:  Post post = new Post();

   2:  post = Post.Find(8);

   3:  using (TransactionScope tran=new TransactionScope ())

   4:  {

   5:      try

   6:      {

   7:          for (int i = 0; i < 5; i++)

   8:          {

   9:              //创建comment

  10:              Comment comment = new Comment();

  11:              comment.Author = "hzd-" + i;

  12:              comment.DateAdded = DateTime.Now;

  13:              comment.Text = "comment" + i + " content!";

  14:              comment.Post = post;

  15:              comment.Save();

  16:          }

  17:          post.Text = "castle active record  Cascade";

  18:          post.Update();

  19:          tran.VoteCommit();

20:

  21:      }

  22:      catch

  23:      {

  24:          tran.VoteRollBack();

  25:      }

  26:  }

27:

3、级联删除

删除一个post

   1:  Post post = new Post();

   2:  post = Post.Find(1);

   3:  post.Delete();

删除一个post的一个comment

   1:  using (new SessionScope())

   2:  {

   3:      Post post = new Post();

   4:      post = Post.Find(8);

   5:      int count = post.Comments.Count;

   6:      post.Comments.RemoveAt(0);

   7:      post.Update();

   8:  }

特别注意

   1:  [HasMany(Lazy = true, Cascade = ManyRelationCascadeEnum.AllDeleteOrphan, Inverse = true)]

   2:  public IList<Comment> Comments { get; set; }

设置One-To-Many 中 One方(本文中的post) HasManyAttribute的Inverse属性为true

Inverse属性指定了双向关联中的所有者，它的默认值为false。

Inverse 为true是，关联关系的维护者为主表(即posts表)。

为false时，关联关系的维护者为子表(即comments表)，如果子表设置了外键不为null，会出现

的错误。