One of my friends asked me to do a site using WordPress for his travel agency.
There should be ability to him, to add tour packages and update them, and also web site visitors should have a chance to register as a member on site and upload their photos, write reviews and rate each tour packages. I made a content management system for this, simply with php and SQL, but I don’t know how to attach that system to WordPress. I don’t know if there is a way to do so.
Please tell me, then I can inform to my friend that it is impossible.
You can do this through the WordPress APIs without writing any MySQL.
Use custom post types for your different content types and WordPress already handles subscriber registration, plugins like BuddyPress extend that.
If you want more specific help please include some code.