To use the Azure Library for Lucene.NET and Lucene.NET from a Visual Studio project, you must add a reference to both the AzureDirectory project or assembly, and the Lucerne.NET project or assembly. You must also add the following using statements to your
Lucene.NET is a .NET implementation of Lucene (http://lucene.apache.org/) and provides full-text indexing and search of documents. Documents are composed of multiple fields and do not have a predefined schema. When
performing a query against the index, you can search across multiple fields within a document. Lucene.NET doesn't directly integrate with SQL Database; instead you must perform a query against a database and construct a Document from the results, which is
then cataloged by Lucene.Net. For more information on Lucene.NET, see
This library allows you to expose blob storage as a Lucene.NET.Store.Directory object, which Lucene.NET uses as persistent storage for its catalog. More information on the Azure Library for Lucene.NET, as well as the latest version, can be found on the project
homepage at http://code.msdn.microsoft.com/AzureDirectory.
The current version of the Azure Library (as of 3/9/2011) may require modification before using it in your solution. Specifically:
The following code creates an AzureDirectory object and uses it as a parameter when creating the IndexWriter:
AzureDirectory azureDirectory =
IndexWriter indexWriter =
As mentioned previously, Lucene.NET is not integrated directly with SQL Database and is based on indexing 'documents' that contain multiple fields. In order to index data from SQL Database, you must query the database and create a new Document object for
each row. Individual columns can then be added to the Document. The following code illustrates querying a SQL Database that contains information on individual bloggers, and then adding the ID and Bio column information to the Lucene index using an IndexWriter
// Create the AzureDirectory against blob storage and create a catalog named 'Catalog'
// Create a DataSet and fill it from SQL Database
DataSet ds =
(SqlConnection sqlCon =
SqlCommand sqlCmd =
sqlCmd.Connection = sqlCon;
sqlCmd.CommandType = CommandType.Text;
// Only get the minimum fields we need; Bio to index, Id so search results
// can look up the record in SQL Database
"select Id, Bio from bloggers"
SqlDataAdapter sqlAdap =
DataTable dt = ds.Tables;
(dt.Rows.Count > 0)
// Create the Document object
Document doc =
// Populate the document with the column name and value from our query
// Write the Document to the catalog
// Close the writer
Note: The above sample returns all rows and adds them to the catalog. In a production application you will most likely only want to add new or updated rows.
After you have added documents to the catalog, you can perform a search against them using the IndexSearcher. The following example illustrates how to create perform a search against the catalog for a term contained in the 'Bio' field and return the Id of
// Create the AzureDirectory for blob storage
// Create the IndexSearcher
IndexSearcher indexSearcher =
// Create the QueryParser, setting the default search field to 'Bio'
QueryParser parser =
// Create a query from the Parser
Query query = parser.Parse(searchString);
// Retrieve matching hits
Hits hits = indexSearcher.Search(query);
// Loop through the matching hits, retrieving the document
i = 0; i < hits.Length(); i++)
//Retrieve the string value of the 'Id' field from the
Based on the Id, you can perform a query against SQL Database to return additional fields from the matching record.
I'm new to Lucene.net and azure both of whcih I'm learning. This article is interesting but I also need to know how to handle full-text search after an update, delete or insert of new table rows. Can you also give examples?