There are many times where you would probably want to extract database from web. Through websites a lot of data can be gathered about the people that fill out online forms on the site contact pages. Unfortunately, once that information is submitted, you cannot have access to that information. The information is the private property of the site administrator. You cannot have access to this information unless you are the site administrator. If you are the site administrator your form tool should compile the information for you into a file for later use. The only data that you can extract database form web is information that is publicly displayed on the website. You can use a website scraper to do this.