How to retrieve the fields and respective values from a single document search using dotnet lucene? - lucene.net

Question

I have a | delimited txt document in which i have fields like ScenarioId, Input value, database value
I am indexing these values.
doc.Add(new Field("Database value", List.Databasevalue, Field.Store.YES, Field.Index.ANALYZED));
var parser = new QueryParser(Lucene.Net.Util.Version.LUCENE_30, "Database value", analyzer);
Console.WriteLine("Text found: {0}" + Environment.NewLine, document.Get("Database value"));
Scenario Id|Input value|Database value
1|Akshay|Akshay Kumar
2|Akshath|Akshath T
3|Paul|John paul
4|Abraham|Abraham Joseph
5|Morris|Morris Johnson
Since my input is only one document. I dont care about the doc number. If there is any match i need to retrieve the respective database value from the input file and respective score. How do I achieve it ? There is a Get function in Document I don't know how does it work! Can someone help me out as there is limited resources available for dotnet lucene

Answer 1

I'm still a bit unclear about what you need, but here is some sample code (in the form of an xUnit test) for indexing docs, performing a search and then reading a document back in Lucene.NET 4.8.
[Fact]
public void StandardAnalyzerExample() {
Directory indexDir = new RAMDirectory();
Analyzer standardAnalyzer = new StandardAnalyzer(LuceneVersion.LUCENE_48);
IndexWriterConfig indexConfig = new IndexWriterConfig(LuceneVersion.LUCENE_48, standardAnalyzer);
indexConfig.UseCompoundFile = true;
IndexWriter writer = new IndexWriter(indexDir, indexConfig);
SearcherManager searcherManager = new SearcherManager(writer, applyAllDeletes: true, new SearchWarmer());
Document doc = new Document();
doc.Add(new StringField("examplePrimaryKey", "001", Field.Store.YES));
doc.Add(new TextField("exampleField", "Unique gifts are great gifts.", Field.Store.YES));
writer.AddDocument(doc);
doc = new Document();
doc.Add(new StringField("examplePrimaryKey", "002", Field.Store.YES));
doc.Add(new TextField("exampleField", "Everyone is gifted.", Field.Store.YES));
writer.AddDocument(doc);
doc = new Document();
doc.Add(new StringField("examplePrimaryKey", "003", Field.Store.YES));
doc.Add(new TextField("exampleField", "Gifts are meant to be shared.", Field.Store.YES));
writer.AddDocument(doc);
writer.Commit();
searcherManager.MaybeRefreshBlocking();
IndexSearcher indexSearcher = searcherManager.Acquire();
try {
QueryParser parser = new QueryParser(LuceneVersion.LUCENE_48, "exampleField", standardAnalyzer);
Query query = parser.Parse("everyone");
TopDocs topDocs = indexSearcher.Search(query, int.MaxValue);
int numMatchingDocs = topDocs.ScoreDocs.Length;
Assert.Equal(1, numMatchingDocs);
Document docRead = indexSearcher.Doc(topDocs.ScoreDocs[0].Doc); //this is how you read back a doc
string primaryKey = docRead.Get("examplePrimaryKey");
Assert.Equal("002", primaryKey);
} finally {
searcherManager.Release(indexSearcher);
}
}
}