Export Documents saved as Blob / Binary from SQL Server

 https://www.jitendrazaa.com/blog/sql/sqlserver/export-documents-saved-as-blob-binary-from-sql-server/

Export Documents saved as Blob / Binary from SQL Server

T-SQL Scripts to Export Blob or Binary data stored in SQL Server

I tried many ways to export files or documents saved as binary (Blob) datatypes in SQL Server. However, finally came up with below solution which worked very well. Below script was used to export around 25GB of files stored in SQL Server.

To understand this, lets create a table in Database which will store files from local system into SQL Server as binary / Blob .

1	CREATE TABLE [dbo].[Document](

2	[Doc_Num] [numeric](18, 0) IDENTITY(1,1) NOT NULL,

3	[Extension] [varchar](50) NULL,

4	[FileName] [varchar](200) NULL,

5	[Doc_Content] [varbinary](max) NULL

6	) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

How to Insert Blob into Database

For demo purpose, we will save two files in our table using below queries

1	INSERT [dbo].[Document] ([Extension] ,[FileName] , [Doc_Content] )

2	SELECT 'pdf', 'Salesforce Lightning.pdf',[Doc_Data].*

3	FROM OPENROWSET

4	(BULK 'C:\G2\My POC\Blog\SQL Server\Source\lightning.pdf', SINGLE_BLOB)  [Doc_Data]

5

6	INSERT [dbo].[Document] ([Extension] ,[FileName] , [Doc_Content] )

7	SELECT 'html', 'Progress.html',[Doc_Data].*

8	FROM OPENROWSET

9	(BULK 'C:\G2\My POC\Blog\SQL Server\Source\Progress.html', SINGLE_BLOB)  [Doc_Data]

If we try to see content in actual table, it will look like

Insert Blob into Database

Export Blob From SQL Server and save it as a file

For demo purpose, we want to save documents on local disc. We will use Doc_Num to be created as folder and document will be saved in that folder. To create folders using SQL Server, we will use stored procedure CreateFolder created in this post.
Note : We will create only one folder per document. If multiple nested folder needs to be created then we need to iterate through each folder and call CreateFolder stored procedure for each folder. Its explained in this blog post.

Now time to see actual T-SQL which will iterate through all documents, create folder and save Blob as a file on local disc.

1

USE [POC]

2	DECLARE @outPutPath varchar(50) = 'C:\G2\My POC\Blog\SQL Server\Extract Blob'

3	, @i bigint

4	, @init int

5	, @data varbinary(max)

6	, @fPath varchar(max)

7	, @folderPath  varchar(max)

8

9	--Get Data into temp Table variable so that we can iterate over it

10	DECLARE @Doctable TABLE (id int identity(1,1), [Doc_Num]  varchar(100) , [FileName]  varchar(100), [Doc_Content] varBinary(max) )

11

12	INSERT INTO @Doctable([Doc_Num] , [FileName],[Doc_Content])

13	Select [Doc_Num] , [FileName],[Doc_Content] FROM  [dbo].[Document]

14

15	--SELECT * FROM @table

16

17	SELECT @i = COUNT(1) FROM @Doctable

18

19	WHILE @i >= 1

20

BEGIN

21

22

SELECT

23	@data = [Doc_Content],

24	@fPath = @outPutPath + '\'+ [Doc_Num] + '\' +[FileName],

25	@folderPath = @outPutPath + '\'+ [Doc_Num]

26	FROM @Doctable WHERE id = @i

27

28	--Create folder first

29	EXEC  [dbo].[CreateFolder]  @folderPath

30

31	EXEC sp_OACreate 'ADODB.Stream', @init OUTPUT; -- An instace created

32	EXEC sp_OASetProperty @init, 'Type', 1;

33	EXEC sp_OAMethod @init, 'Open'; -- Calling a method

34	EXEC sp_OAMethod @init, 'Write', NULL, @data; -- Calling a method

35	EXEC sp_OAMethod @init, 'SaveToFile', NULL, @fPath, 2; -- Calling a method

36	EXEC sp_OAMethod @init, 'Close'; -- Calling a method

37	EXEC sp_OADestroy @init; -- Closed the resources

38

39	print 'Document Generated at - '+  @fPath

40

41	--Reset the variables for next use

42	SELECT @data = NULL

43	, @init = NULL

44	, @fPath = NULL

45	, @folderPath = NULL

46	SET @i -= 1

47

END

Variable @outPutPath stores root folder path, where folders will be created and Blob content would be exported into it as a file.

Below image shows output in action :

SQL Server Export Blob as File