Script to save varbinary data to disk

I have some varbinary data stored in a table in MS Sql Server 2005. Does anyone have SQL code that takes a query as input (lets say the query guarantees that a single column of varbinary is returned) and outputs the bytes to disk (one file per row?) I'm sure this has been asked a thousand times before, but Googling comes up with mostly .net solutions. I want an SQL solution.

Solution 1:

The BCP approach does not work for me. The bytes it writes to disk cannot be deserialized back to the .net objects I stored. This means that the bytes on disk aren't equivalent to what's stored. Perhaps BCP is writing some kind of header. I'm not sure.

I found the following code here at the bottom of the article. It works great! Although it was intended for stored BMP images, it works with any varbinary.

DECLARE @SQLIMG VARCHAR(MAX),
    @IMG_PATH VARBINARY(MAX),
    @TIMESTAMP VARCHAR(MAX),
    @ObjectToken INT

DECLARE IMGPATH CURSOR FAST_FORWARD FOR 
        SELECT csl_CompanyLogo from mlm_CSCompanySettingsLocalizations

OPEN IMGPATH 

FETCH NEXT FROM IMGPATH INTO @IMG_PATH 

WHILE @@FETCH_STATUS = 0
    BEGIN
        SET @TIMESTAMP = 'd:\' + replace(replace(replace(replace(convert(varchar,getdate(),121),'-',''),':',''),'.',''),' ','') + '.bmp'

        PRINT @TIMESTAMP
        PRINT @SQLIMG

        EXEC sp_OACreate 'ADODB.Stream', @ObjectToken OUTPUT
        EXEC sp_OASetProperty @ObjectToken, 'Type', 1
        EXEC sp_OAMethod @ObjectToken, 'Open'
        EXEC sp_OAMethod @ObjectToken, 'Write', NULL, @IMG_PATH
        EXEC sp_OAMethod @ObjectToken, 'SaveToFile', NULL, @TIMESTAMP, 2
        EXEC sp_OAMethod @ObjectToken, 'Close'
        EXEC sp_OADestroy @ObjectToken

        FETCH NEXT FROM IMGPATH INTO @IMG_PATH 
    END 

CLOSE IMGPATH
DEALLOCATE IMGPATH

Solution 2:

I am adding this to build on JohnOpincar's answer, so that others who want to use LinqPad can get a working solution faster.

/*
This LinqPad script saves data stored in a VARBINARY field to the specified folder.
1. Connect to SQL server and select the correct database in the connection dropdown (top right)
2. Change the Language to C# Program
3. Change "Attachments" to the name of your table that holds the VARBINARY data
4. Change "AttachmentBuffer" to the name of the field that holds the data
5. Change "Id" to the unique identifier field name
6. Change "1090" to the identity of the record you want to save
7. Change the path to where you want to save the file. Make sure you choose the right extension.

Notes: Windows 10 may give you "Access Denied" error when trying to save directly to C:\. Rather save to a subfolder.
*/

void Main()
{
    var context = this;
    var query = 
        from ci in context.Attachments
        where ci.Id == 1090
        select ci.AttachmentBuffer
    ;
    byte[] result = query.Single().ToArray();
    File.WriteAllBytes(@"c:\DEV\dumpfile.xlsx", result);
    Console.WriteLine("Done");
}

Solution 3:

You can use BCP, not T-SQL, but works well.

BCP "SELECT FileContent FROM table WHERE ID = 1" queryout "C:\file.txt" -T

Solution 4:

I know it's an old post, but I figured out why the following doesn't work and how to fix it:

BCP "SELECT FileContent FROM table WHERE ID = 1" queryout "C:\file.JPG" -T -N

The reason is bcp put Prefix Length at the very beginning of the file. It is either 4 bytes or 8 bytes, depends on data type of FileContent column (text, ntext, image: 4 varchar(max), varbinary(max) : 8 Refer to https://msdn.microsoft.com/en-us/library/ms190779.aspx)

Use a binary editor, like the one in Visual Studio, to remove the prefix bytes, and everything runs perfectly. :-)

Solution 5:

If you have linqpad, this works:

void Main()
{
    var context = this;
    var query = 
        from ci in context.Images
        where ci.ImageId == 10
        select ci.Image
    ;
    var result = query.Single ();
    var bytes = Convert.FromBase64String(result);
    File.WriteAllBytes(@"c:\image.bmp", bytes);
}