递归删除SQLite的项目 [英] Recursive delete of SQLite items

问题描述

SQLite的分贝例如：

SQLite db example:

**我没有创建数据库，这是Android的书签分贝，这是我访问使用contentproviders。

** I don't create the db, it's Android Bookmarks db, which I access using contentproviders.

**从我一些搜索后了解到，SQLite不支持外键约束，但触发器是可能的 - 的 http://www.sqlite.org/cvstrac/wiki?p=ForeignKeyTriggers

** from what I understand after some searches, SQLite doesn't support foreign key constraints but triggers are possible - http://www.sqlite.org/cvstrac/wiki?p=ForeignKeyTriggers

文件夹栏 - > 0 =不是一个文件夹（假），1 =一个文件夹（真）

FOLDER column -> 0 = not a folder (false), 1 = a folder (true)

父栏 - >持有其夹在 ID

PARENT column -> holds the ID of its folder

ID  TITLE     FOLDER   PARENT
1   folder1      1        0
2   item1        0        1
3   item2        0        1
4   folder2      1        1
5   item1        0        4
6   item2        0        4
7   folder3      1        4
8   item1        0        7
9   item2        0        7

...等

在我的Andr​​oid应用程序，我试图递归删除一个SQLite数据库项目。
我的第一个文件夹的ID，我想循环查找所有它的内部项目（更多的文件夹和项目）。

On my Android app, I'm trying to recursively delete items from a SQLite db. I have the ID of the first folder and I want to loop to find all it's inner items (more folders and items).

例如 - 我有ID = 1，这样我就可以很容易地通过要求所有项目的查询，他们的父母是ID = 1删除ID的2和3，得到物品ID，然后删除

For example - I have ID=1, so I can easily delete IDs 2 and 3 by requesting a query of all items their parent is ID=1, get items IDs and then delete.

问题是我无法弄清楚如何删除ID = 4，其内部项目（项目1，项目2，和folder3），然后folder3内的物品。

The problem is I can't figure out how to delete ID=4 and its inner items (item1, item2, and folder3) and then folder3 inner items.

很想一些帮助这个！一直试图小时：\\

Would love some help with this! been trying for hours :\

谢谢！

推荐答案

如果在Java中则是这样的，我认为，我认为像 findNextChildId 不应该是一个问题的功能

If in java then something like this I think, I think functions like findNextChildId should not be a problem:

 deleteFolderAndSub(int id){
        int childId = findNextChildId(id);
         //Let -1 be that there are no more children
        while (childId!=-1){
        if (checkIfFolder(childId)){
            deleteFolderAndSub(childId);
    //on exiting from above function folder should be empty so it can be deleted without problem
            deleteEmptyFolder(id);
        } else {
            deleteitem(id);
        }
//it should be while loop and we have to find another child inside the loop
        childId = findNextChildId(id)
      }
    }

findNextChildId(int parentId){
   Coursor yourCoursor;
  while(yourCoursor.moveToNext()){
    if (parentId==yourCoursor.getInt("PARENT")){
        yourCoursor.getInt("ID");
    }
  }
}

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