@tunde
Actually I didn't use server side scripts to filter data, I just thought of a temporary solution for this problem. I understand that using server side scripts to filter data maybe a wrong use of Dreamfactory features. I'd sugest you to try the solution pointed by @drewpearce.
But if you're feeling adventurous, you can try something like the "Modify query results after database GET" example in this link: https://github.com/dreamfactorysoftware/dsp-core/wiki/Server-Side-Scripting.