how to insert and retrieve a 20mb pdf file from mysql database?

if this is a web app, i would personally store the pdf in a seperate folder and only the document name in the database. i am sure this would be the way without it being web based also.

is it web based?

yes this is a web app using php,mysql
but i am simply designing a database by phpadmin

andydeans's suggestion is really good.

yes this is a web app using php,mysql
but i am simply designing a database by phpadmin

Are you trying to develop a test site/database?

If it is using php/mysql then for definate you want to store the files in a seperate folder on your server. (Possible password protect this directory) then in mysql, create a docs table, store the filename in here and add a docid PK AI just in ase you get the same filename twice.

if you want to store in the database check this out:

http://www.php-mysql-tutorial.com/wikis/mysql-tutorials/uploading-files-to-mysql-database.aspx

if you do not want to store in the database then check this this other thread out:

http://www.daniweb.com/forums/thread214601.html

Thank u andy.
it's workin.