I am building a website. I have created the database in MySQL. I need to build the web pages really fast! Is there a PHP CMS with which I can easily create the webpages with forms that can modify my database tables? The point is that I don't want to code it using plain PHP or MVC frameworks either. I looked at other CMSs' like Drupal and Joomla but it looks like its difficult to make them use custom tables.
You can go for:
Have a look at this for manipulating your database really fast:
In the end, if you have good knowledge of php, you can go for:
Kohana (Improved alternative of CodeIgniter)
You should take a second look at Drupal, the CCK module might just do exactly what you want. With CCK you can define custom fields for your content types and create essentially any kind of web form you want. You can then use the Views module to display your data in various ways. There are a variety of very useful predefined fields (for Files, Images, Dates with Datepicker, References to other content, email adresses ...).
If you are not restricted to PHP I would recommend Django (written in Python) which makes creating web forms really, really easy.
With both it is also possible to import existing data, although that might take a bit of work.