How do I link the File Table with my existing table in SQL server - sql

Question

I have a requirement of saving employees image in database. I have been asked to use File Tables. After googling on this I got some fine contents as to how to get started with File Tables. And I managed to create them, also inserting data to these tables is as simple as copy/paste to specified folder and the data gets inserted into the table. The problem is how do I relate each employee row set with their respective images
The overall flow will be like the employee will upload his/her image or doc through front end, which will save the image on the server. the problem is how to add reference of employee with its respective image. One option can be having a FileName column in the employee table which refers to the name column in the FileTable, but I need something more efficient such as relating the id's. Any other way of achieving this would be appreciated.

Answer 1

First of it consumed a lot of time to get things right as filetable being a new feature introduced from SQLSERVER 2012 onwards. Secondly this is the approach I took to counter my issue. I will be providing some usefull links to make life easier for other developers. Hope it helps.
File table is almost similar to normal SQL tables, but has some configurations to be made to get it started, as it resides in a separate section of your database, inside tables-->FIleTables. Since the table structure is predefined, you cannot change the table schema. So the approach I took is to refer the stream_id as the reference key to link with the table that I want to use and handle the constrains logic through stored procedure. In my scenario the Employee table will have a stream_id column which will be linked to the File table via stream_id, also to make rows in the File table unique, I inserted the Employee Id as the name of the stored image and not the actual name of the file. With this even if anyone tries to insert the file directly by copy/paste it wouldn't have any relation with the Employee table, also you can provide access right to give desired permission. Check the links for more details. And that's it, with a little bit of tweaks I was able to solve my issue.
Below SQL scripts will be helpful to activate file stream at instance level at one shot.
EXEC sp_configure filestream_access_level, 2
RECONFIGURE
GO
--For new DB
CREATE DATABASE <DATABASE name>
WITH FILESTREAM
(
NON_TRANSACTED_ACCESS = FULL,
DIRECTORY_NAME = N'<DIRECTORY name>'
);
GO
--If you have an existing DB
ALTER DATABASE <DATABASE name>
ADD FILEGROUP <File group name>
CONTAINS FILESTREAM
GO
ALTER DATABASE <DATABASE name>
ADD FILE (NAME='<File group name>', FILENAME='<DIRECTORY name>')
TO FILEGROUP <File group name>
GO
ALTER DATABASE <DATABASE name>
SET FILESTREAM ( NON_TRANSACTED_ACCESS = FULL, DIRECTORY_NAME = N'<File
group name>')
GO
use <DATABASE name>
GO
CREATE TABLE <Filetable NAME> AS FileTable;
GO
Also some links which are very helpful:
https://www.mssqltips.com/sqlservertip/2667/filetable-feature-in-sql-server-2012/
http://sql-articles.com/articles/general/working-with-filetables/
https://michaelfirsov.wordpress.com/working-with-sql-server-file-tables-part-1/
https://michaelfirsov.wordpress.com/working-with-sql-server-file-tables-part-2/
https://msdn.microsoft.com/pl-pl/library/gg492084(v=sql.110).aspx
Thanks.

Answer 2

Wouldn't just having a "joining (many-to-many) table" in between employer and the filetable be just as easy? You wouldn't have to use it as a many-to-many table. Call it EmployeeImages and add a description attribute/property i.e "Hiring photo", "Just got fired photo". with both primary keys from employee and filetable. simples!

Answer 3

You have to insert in your program the code for copying file.
File.Copy(...) Instead of just copying and pasting into file system.
So that, each instance that your File.Copy executes, you can get its respective stream_id, which then you attach on your employees table..