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 .
CREATE TABLE [dbo].[Document]( [Doc_Num] [numeric](18, 0) IDENTITY(1,1) NOT NULL, [Extension] [varchar](50) NULL, [FileName] [varchar](200) NULL, [Doc_Content] [varbinary](max) NULL ) 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
INSERT [dbo].[Document] ([Extension] ,[FileName] , [Doc_Content] )
SELECT 'pdf', 'Salesforce Lightning.pdf',[Doc_Data].*
FROM OPENROWSET
(BULK 'C:\G2\My POC\Blog\SQL Server\Source\lightning.pdf', SINGLE_BLOB) [Doc_Data]
INSERT [dbo].[Document] ([Extension] ,[FileName] , [Doc_Content] )
SELECT 'html', 'Progress.html',[Doc_Data].*
FROM OPENROWSET
(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
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.
USE [POC] DECLARE @outPutPath varchar(50) = 'C:\G2\My POC\Blog\SQL Server\Extract Blob' , @i bigint , @init int , @data varbinary(max) , @fPath varchar(max) , @folderPath varchar(max) --Get Data into temp Table variable so that we can iterate over it DECLARE @Doctable TABLE (id int identity(1,1), [Doc_Num] varchar(100) , [FileName] varchar(100), [Doc_Content] varBinary(max) ) INSERT INTO @Doctable([Doc_Num] , [FileName],[Doc_Content]) Select [Doc_Num] , [FileName],[Doc_Content] FROM [dbo].[Document] --SELECT * FROM @table SELECT @i = COUNT(1) FROM @Doctable WHILE @i >= 1 BEGIN SELECT @data = [Doc_Content], @fPath = @outPutPath + '\'+ [Doc_Num] + '\' +[FileName], @folderPath = @outPutPath + '\'+ [Doc_Num] FROM @Doctable WHERE id = @i --Create folder first EXEC [dbo].[CreateFolder] @folderPath EXEC sp_OACreate 'ADODB.Stream', @init OUTPUT; -- An instace created EXEC sp_OASetProperty @init, 'Type', 1; EXEC sp_OAMethod @init, 'Open'; -- Calling a method EXEC sp_OAMethod @init, 'Write', NULL, @data; -- Calling a method EXEC sp_OAMethod @init, 'SaveToFile', NULL, @fPath, 2; -- Calling a method EXEC sp_OAMethod @init, 'Close'; -- Calling a method EXEC sp_OADestroy @init; -- Closed the resources print 'Document Generated at - '+ @fPath --Reset the variables for next use SELECT @data = NULL , @init = NULL , @fPath = NULL , @folderPath = NULL SET @i -= 1 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 :
Hi,
I am trying to use your code to export varbinary from the database to file, but I am not seeing any folders being created or files been exported. No errors.
So, will the files get created on the database server or on the machine on which we run this T-sql ?.
Thanks for your help.
It would be created in local machine. In above code, line 2, you need to make sure that path exists already. Any sub folder needed would be handled by above code
Thanks for the response. Yes, the path does exists. And now when I uncommented the raiserror stmt from the [dbo].[CreateFolder] procedure ( I used your code for this too), I am getting below error-
Msg 50000, Level 16, State 1, Procedure CreateFolder, Line 36
On printing values for @init ,OLEfolder as seen in the below code –
— check if folder exists
EXEC @init=sp_OAMethod @OLEfilesytemobject, ‘FolderExists’, @OLEfolder OUT, @newfolder
print @OLEfolder
print @init
—-Results—-
0
0
Msg 50000, Level 16, State 1, Procedure CreateFolder, Line 36
This tell me, that the sp_OAMethod is not able to find the folder .
Please advise. Thanks again !
Oh found out that the files are being exported on the database server.
Thanks again for posting this code.
Hi, I am experiencing the same problem. How did you manage to solve it?
Hi,
I tried to get this working and everything seems to process fine without no errors, I get Documents generated at – but when i navigate to the folder; the folder structure has been created e.g. there is 4 attachments so folder 1,2,3,4 have been created but there is nothing in the folders.
Please help!!!!
Thank you Jitendra, exactly what I was looking for.
Just applied it to create a demo about “Compressed” data using the Compress functionality.
Saving a columns value as a file (extension = .zip). 7-zip flawlessly extracts the data within to it’s original uncompressed value.
Hi Jitendra,
For me above query got executed and stored the attachments in my given path also but attachment size is showing 0 Bytes
Good Heavens – this is truly great. I really appreciate google (and obviously this kind of results and your efforts). THANK YOU!
How is it possible to create folders and export the files to a shared network drive instead of the local machine? thanks in advance!
Hi,
I can run the scripts successfully but when i go into the folders the scripts have created there is nothing in the folders. The contents are not being exported.
Please help!
Hi,
I can run the script successful and it creates the folder structures but it does not have any contents in the folder. I am using a local SQL database for testing purposes.
Please help!
Thank you Jitendra, it really helped me creating files from BLOB data.
I am able to create file on specified path but the I am not able to open the file. Below is the message appears when double click on the file,
We’re sorry. We can’t open “File_Name” because we found a problem with its contents.
Details,
The file is corrupt and cannot be opened.
Thanks,
Shardul Pathak
Hi Jitendra,
I am creating file from BLOB data using SQL, file created successfully but not able to open the file. Below is the message appears when trying to open the file,
We’re sorry. We can’t open “file_name” because we found a problem with its contents.
Details, The file is corrupt and cannot be opened.
It’s seem work with role system admin. If I just want to export by normal SQL admin. How can I do that?
Because I don’t want to grant full permission for some guys want to export file.