c# - Lucene.net - 无法进行多词搜索

Question

我在我的 lucene 索引中存储了以下文档:

{
"id" : 1,
"name": "John Smith"
"description": "worker"
"additionalData": "faster data"
"attributes": "is_hired=not"
},
{
"id" : 2,
"name": "Alan Smith"
"description": "hired"
"additionalData": "faster drive"
"attributes": "is_hired=not"
},
{
"id" : 3,
"name": "Mike Std"
"description": "hired"
"additionalData": "faster check"
"attributes": "is_hired=not"
}

现在我想搜索所有字段以检查给定值是否存在:

search term: "John data check"

这会让我返回带有 ID 1 和 3 的文档。但它没有，为什么？

var analyzer = new StandardAnalyzer(Lucene.Net.Util.Version.LUCENE_30);

BooleanQuery mainQuery = new BooleanQuery();
mainQuery.MinimumNumberShouldMatch = 1;

var cols = new string[] {
                         "name",
                         "additionalData"
                        };

 string[] words = searchData.text.Split(new string[] { " " }, StringSplitOptions.RemoveEmptyEntries);

 var queryParser = new MultiFieldQueryParser(Lucene.Net.Util.Version.LUCENE_30, cols, analyzer);

 foreach (var word in words)
 {
    BooleanQuery innerQuery = new BooleanQuery();
    innerQuery.MinimumNumberShouldMatch = 1;

    innerQuery.Add(queryParser.Parse(word), Occur.SHOULD);

    mainQuery.Add(innerQuery, Occur.MUST);
 }

 TopDocs hits = searcher.Search(mainQuery, null, int.MaxValue, Sort.RELEVANCE);

 //hits.TotalHits is 0 !!

Answer 1

您构造的查询基本上要求所有三个词都匹配。

您将每个单词包装在 BooleanQuery 中用SHOULD条款。这相当于直接使用内部查询(您只是添加了一个不改变查询行为的间接查询)。 bool 查询只有一个子句，它应该与 bool 查询匹配。

然后，您将这些中的每一个包装在另一个 bool 查询中，这次使用 MUST每个条款。这意味着每个子句都必须匹配才能匹配查询。

对于 BooleanQuery匹配，所有 MUST必须满足子句，如果没有，则至少为 MinimumNumberShouldMatch SHOULD条款必须得到满足。将该属性保留为默认值，因为记录的行为是:

By default no optional clauses are necessary for a match (unless there are no required clauses).

实际上，您的查询是(为简单起见，假设没有 MultiFieldQueryParser):

+(john) +(data) +(check)

或者，以树的形式:

BooleanQuery
    MUST: BooleanQuery
        SHOULD: TermQuery: john
    MUST: BooleanQuery
        SHOULD: TermQuery: data
    MUST: BooleanQuery
        SHOULD: TermQuery: check

可以简化为:

BooleanQuery
    MUST: TermQuery: john
    MUST: TermQuery: data
    MUST: TermQuery: check

但是你想要的查询是:

BooleanQuery
    SHOULD: TermQuery: john
    SHOULD: TermQuery: data
    SHOULD: TermQuery: check

因此，删除 mainQuery.MinimumNumberShouldMatch = 1;行，然后替换你的 foreach正文包含以下内容，它应该可以完成工作:

mainQuery.Add(queryParser.Parse(word), Occur.SHOULD);

---

好的，这是一个完整的例子，对我有用:

var analyzer = new StandardAnalyzer(Lucene.Net.Util.Version.LUCENE_30);

var directory = new RAMDirectory();

using (var writer = new IndexWriter(directory, analyzer, true, IndexWriter.MaxFieldLength.UNLIMITED))
{
    var doc = new Document();
    doc.Add(new Field("id", "1", Field.Store.YES, Field.Index.NOT_ANALYZED));
    doc.Add(new Field("name", "John Smith", Field.Store.NO, Field.Index.ANALYZED));
    doc.Add(new Field("additionalData", "faster data", Field.Store.NO, Field.Index.ANALYZED));
    writer.AddDocument(doc);

    doc = new Document();
    doc.Add(new Field("id", "2", Field.Store.YES, Field.Index.NOT_ANALYZED));
    doc.Add(new Field("name", "Alan Smith", Field.Store.NO, Field.Index.ANALYZED));
    doc.Add(new Field("additionalData", "faster drive", Field.Store.NO, Field.Index.ANALYZED));
    writer.AddDocument(doc);

    doc = new Document();
    doc.Add(new Field("id", "3", Field.Store.YES, Field.Index.NOT_ANALYZED));
    doc.Add(new Field("name", "Mike Std", Field.Store.NO, Field.Index.ANALYZED));
    doc.Add(new Field("additionalData", "faster check", Field.Store.NO, Field.Index.ANALYZED));
    writer.AddDocument(doc);
}

var words = new[] {"John", "data", "check"};
var parser = new MultiFieldQueryParser(Lucene.Net.Util.Version.LUCENE_30, new[] {"name", "additionalData"}, analyzer);


var mainQuery = new BooleanQuery();
foreach (var word in words)
    mainQuery.Add(parser.Parse(word), Occur.SHOULD); // Should probably use parser.Parse(QueryParser.Escape(word)) instead

using (var searcher = new IndexSearcher(directory))
{
    var results = searcher.Search(mainQuery, null, int.MaxValue, Sort.RELEVANCE);
    var idFieldSelector = new MapFieldSelector("id");

    foreach (var scoreDoc in results.ScoreDocs)
    {
        var doc = searcher.Doc(scoreDoc.Doc, idFieldSelector);
        Console.WriteLine("Found: {0}", doc.Get("id"));
    }
}