Skip to main content

Full-Text Search with PDF in Microsoft SQL Server

Last week I get interesting task to develop. The task was to search input text in PDF file stored in database as FileStream. The task implementation took me some time so I decided to share it with other developers.

Here we are going to use SQL Server 2008 R2 (x64 Developers Edition), external driver from Adobe, Full-Text Search technology and FileStream technology.Because this sems a little bit comlicated let`s make this topic clear and do it step by step.

1) Enable FileStream - this part is pretty easy, just check wheter You already have enabled filestream on Your SQL Server instance - if no simply enable it as in the picture below.

Picture 1. Enable filestream in SQL Server instance.

2) Create SQL table to store files - mainly ther will be PDF file stored but some others is also be allright. Out table DocumentFile will be created in dbo schema and contain one column primary key with default value as sequential GUID. Important this is out table contains FileStream_Id and FileSource columns which are required do FileStream. Additionaly don`t miss the Extension column because we going need it for Full-Text Search.

Code Snippet
  1. CREATE TABLE dbo.DocumentFiles
  2.     (
  3.     DocumentId uniqueidentifier Primary KEY DEFAULT newsequentialid(),
  4.     AddDate datetime NOT NULL,
  5.     Name nvarchar(50) NOT NULL,
  6.     Extension nvarchar(10) NOT NULL,
  7.     Description nvarchar(1000) NULL,
  8.     FileStream_Id uniqueidentifier NOT NULL,
  9.     FileSource varbinary(MAX) NOT NULL DEFAULT (0x)
  10.     )  ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
  11. --Add default add date for document    
  12. ALTER TABLE dbo.DocumentFiles ADD CONSTRAINT
  13.     DF_DocumentFiles_AddDate DEFAULT sysdatetime() FOR AddDate

3) Installing additional component for PDF file support - by default PDF  files is not supported in SQL Server. To check PDF support installed status just execute following T-SQL command:

Code Snippet
  1. SELECT document_type, path FROM sys.fulltext_document_types WHERE document_type = '.pdf'

If after query execution You have no rows returned, this means You have to install PDF support for SQL Server from here (version for x64). When installation complete, to see PDF file support  is int the sys.fulltext_document_types You must restart You SQL Server instance and then validate extension is in the supported type list.

Picture 2. Properly installed PDF extension.
4) Creating Full-Text Search (FTS) index on DocumentFiles table.

T-SQL query below, enable FTS on databse and then create full-text catalog named Document_Catalog which is required for creating any FTS index on any table in database.

Code Snippet
  1. EXEC sp_fulltext_database 'enable'
  2. GO
  3. IF NOT EXISTS (SELECT TOP 1 1 FROM sys.fulltext_catalogs WHERE name = 'Ducuments_Catalog')
  4. BEGIN
  5.     EXEC sp_fulltext_catalog 'Ducuments_Catalog', 'create';
  6. END

Now it`s time for creating full-text index. But before this, its time for a small inclusion because when You are using Entity Framework Code-First name of You primary key in any table vary between each time table is created. The problem is when creating FTS index on table we have to specified primary key index name. Query presented below retrieves primary key name from  system tables and pass it further queries. Other important thing, as I write above, is Extension column. Here stored file extension have to be stored in the following format '.pdf'. This is required because SQL Server uses it to determine which Full-Text Search driver should be use. Out newly created index has change tracking set to auto so each time new document is added to index it`s automatically added to it. If you want to decide by You own when documents are updated in index set change tracking mode to manually.


Code Snippet
  1. DECLARE @indexName nvarchar(255) = (SELECT Top 1 i.Name from sys.indexes i
  2.                                     Join sys.tables t on  i.object_id = t.object_id
  3.                                     WHERE t.Name = 'DocumentFiles' AND i.type_desc = 'CLUSTERED')
  4.                                     
  5.                                     PRINT @indexName
  6.  
  7. EXEC sp_fulltext_table 'DocumentFiles', 'create', 'Ducuments_Catalog',  @indexName
  8. EXEC sp_fulltext_column 'DocumentFiles', 'FileSource', 'add', 0, 'Extension'
  9. EXEC sp_fulltext_table 'DocumentFiles', 'activate'
  10. EXEC sp_fulltext_catalog 'Ducuments_Catalog', 'start_full'
  11.  
  12. ALTER FULLTEXT INDEX ON [dbo].[DocumentFiles] ENABLE
  13. ALTER FULLTEXT INDEX ON [dbo].[DocumentFiles] SET CHANGE_TRACKING = AUTO


After section four completed its time for our solution testing. For insert file to DocumentFiles table first insert simple data  (Insert Into....) except FileStream_Id and  FileSource. After it next upload file to FileStream directly from SQL Server as presented here or from C# code.

When You have data inserted You are able to query it as simple Full-Text data by using query as in example below.


Code Snippet
  1. SELECT d.* FROM dbo.DocumentFiles d
  2. WHERE Contains(d.FileSource, '%Word%')


Thank you.

Read more...




Popular posts from this blog

Autocomplete control with ASP.NET MVC 4 and jQuery

Almost in each modern website project one of the feature is suggesting user possible items to select when he start typing one of them. Such functionality is done by using control named autocomplete . Under the hood  it consists of at least three elements: UI control which allow user to type some text - mainly this in HTML input of text type Server-side function which serves data to be auto-completed Client-side logic (written in JavaScript) which , by using AJAX, send request to the server asynchronously and then process the results. When we think about creating autocomplete control in ASP.NET MVC 4 we definitely should take a look at  jQueryUI framework. One of the feature of this framework is autocomplete control which enables users to quickly find and select from a pre-populated list of values as they type, leveraging searching and filtering. That sounds very good and is excellently what we are looking for. First step in autocomplete control  creation is creating a

Multithread processing of the SqlDataReader - Producer/Consumer design pattern

In today post I want to describe how to optimize usage of a ADO.NET SqlDataReader class by using multi-threading. To present that lets me introduce a problem that I will try to solve.  Scenario : In a project we decided to move all data from a multiple databases to one data warehouse. It will be a good few terabytes of data or even more. Data transfer will be done by using a custom importer program. Problem : After implementing a database agnostic logic of generating and executing a query I realized that I can retrieve data from source databases faster that I can upload them to big data store through HTTP client -importer program. In other words, data reader is capable of reading data faster then I can process it an upload to my big data lake. Solution : As a solution for solving this problem I would like to propose one of a multi-thread design pattern called Producer/Consumer . In general this pattern consists of a two main classes where: Producer class is respons