generating unique identifiers and dynamic webpage

I have a few questions on a webpage and I want to store the responses to those questions in a database.

But I should be able to retrieve those responses later so I am thinking of generating an identifier(unique for each set of responses) and store that with the responses into the database. And then when I pass that identifier in the URL, a new webpage is dynamically created(from a template) using the responses associated with that identifier.

QUESTIONS

• What algorithm should I use to generate those unique identifiers?(security isn't a very big concern for this application)
• How can I dynamically create a webpage using responses from the DB associated with the identifier?
• I want that link(the URL with the identifier) to be active for few days only(say 7) and after that, it should not work. How to implement this too?