I'd need to index my website on Google and other search engines, though my website is a database of IP addresses and the webpage is dynamically generated like
example.com/show.php?&ip=ipvalue
Would it be possible to index on Google and other search engines every IP address I have on the database by linking directly the direct URL as showed above?
I know how to set up a proper sitemap file to index static content though I cannot understand how I could tell a search engine to index a URL that doesn't physically exist unless the user passes a value which is in the database.
No one (neither human visitors nor search engine bots) knows if a document is created dynamically or if it exists as a static file.
A search engine would have no reason to handle a link to http://example.com/show.php?ip=127.0.0.1 differently from a link to http://example.com/ip/127.0.0.1. By using URL rewriting (e.g., mod_rewrite for Apache), you could rewrite your URLs in such a way.
So: Just link to these pages from a place that search engine crawlers can access.