Can you please explain the difference between PHP and RubyOnRails. I am trying to get a web-based application developed for an online personality test, and would like something secure, has database abilities, graphing abilities, backend calculation capabilities. Please advise! I was told to have the program developed as a Wordpress plugin using PHP. Is this passe, or a good idea? Thank you.
Can you please explain the difference between PHP and RubyOnRails.
PHP is a programming language; Ruby on Rails is a web application development platform using the Ruby language.
I am trying to get a web-based application developed for an online personality test, and would like something secure, has database abilities, graphing abilities, backend calculation capabilities. Please advise! I was told to have the program developed as a Wordpress plugin using PHP.
"told to" ? So I'm guessing you're not a developer yourself? In that case the most important thing is to find a developer that you trust, regardless of what language/platform s/he uses.
Is this passe, or a good idea? Thank you.
Your application sounds perfect for Rails. The idea of creating it as a plugin for Wordpress sounds like welding a basket on a submarine to wash lettuce.
But see my first point above 
Good luck!
Some basic terminology first:
PHP is a language, Ruby is a language. CakePHP or Zend Framework are examples of PHP Web frameworks, and Rails is a Ruby Web framework. There are many others, in both languages. These languages have a lot of following in the Web development community, because they are dynamic (flexible) and there are great hooks into traditional Web workflows. Other languages include Python, C#, even C itself (which is the mother language of Ruby and PHP -- they're both written at the lowest level in C).
Wordpress is a blogging application, written in PHP. It is not, strictly speaking, the same kind of thing as Cake or Zend. Instead, you could use either of those frameworks to create an application similar to Wordpress.
A good programmer could implement your "elevator pitch" requirements using nearly any Web-friendly language or toolkit, and this choice of framework or language should be made by the person who is doing the work. It's their productivity that will be impacted most by this choice, not the possibility of meeting your deliverables.
Unless you are the one who will be coding this, I recommend that you write the clearest possible explanation of your business goals, and put it out for bid. Throw out the highest and lowest bid, and use only as one tiny factor in your decision which language or framework the final product is developed in. You do have a certain responsibility to yourself to choose a popular development style, simply because your prime developer may not be the person who ends up maintaining the thing. You want to stay in one of the larger tents so you can hire someone to pick up the pieces later.
Walter