I agree with the people that stated that storing the pdf file in the database is probable not the best idea. When I workd for a online newspaper I was given an assinment of comming up with a way to store, large in my case, PDF files. I oped out of storing them into the database due to the size of the files and the amount of request there would be for the file. So this is what I did.

1. I created a unique filename for the PDF file.
2. Zip up the PDF file and stored it an a secure location on the server under the new unique filename.
3. Entered the name of the zipped file into the database alonge with all the file characteristics for easy searching.

When someone needed the file, the retrival program woulud unzip it in a tmp directory and upload it to the user then delete the temp file. This saved me space in the db and on the server itself. All I had to due was makesure that the directory with the ziped files where backedup at the same time as the database and all was good in life.