这样的类别树:
root_1
sub_1
sub_2
... to sub_20
每个文档都有一个子类别(如 sub_2).现在，我只在lucene索引中写了sub_2:
Every document has a sub category(like sub_2). Now, I only wrote sub_2 in lucene index:
new NumericField("category",...).setIntValue(sub_2.getID());
我想获取所有 root_1 的文档，使用 BooleanQuery(将 sub_1 合并到 sub_20)在每个条目文档中搜索或写入其他类别:
I want to get all root_1's documents, using BooleanQuery (merge the sub_1 to sub_20) to search or write an other category in every entry document:
new NumericField("category",...).setIntValue(sub_2.getID());
new NumericField("category",...).setIntValue(root_1.getID());//sub_2's ancestor category
哪个是更好的选择?
我将使用类别层次结构的路径枚举/'Dewey Decimal' 表示.也就是说，不是只为第一个根的第二个孩子存储sub_2"，而是存储类似001.002"的东西.
I would use a path enumeration/'Dewey Decimal' representation of the category hierarchy. That is, instead of just storing 'sub_2' for the second child of the first root, store instead something like '001.002'.
要查找根及其所有子项，您可以搜索category:001*".
To find the root and all of its children, you would search on "category:001*".
要仅查找根的子项，您可以搜索category:001.*".
To find only the children of the root, you would search on "category:001.*".
(另请参阅 如何将树数据存储在 Lucene/Solr/Elasticsearch 索引或 NoSQL 数据库中?.)
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