Check if CMS is already installed

[Lundager]

Hello, I'm making my own CMS, not a simple one neither a very advanced one. I just finished my installation page, where users can input their database information, and can continue on to create their admin account. My question is, I'm having a bit of a struggle figuring out, how I should check if the CMS has already been installed, and redirect the users to the login screen. I sneak peaked at wordpresses code, and saw that they check their cache and some other advanced stuff, that I couldn't really understand 100%.

So does anybody have a suggestion on how I should manage to do this, or could tell me how I can do it the same way wordpress does, or something close to that!

Thank you !

[aaarrrggh]

Well... You should know your own app and should therefore be able to check for stuff that would only be present after the application is successfully installed...