Database design tools
Let's see why we need a database design tool.
Although the number of tables in your database will definitely depend on the type of product you are working on, it's highly unlikely that there will be a system doing serious work with less than 10-20 tables. By the time we add tables to manage users, roles, and privileges, we will have 4-5 tables. Add a few tables to audit user actions and we will have double digits. Then, of course, there will be tables to support the core business.
We might have a system that deals with products, customers, and warehouses. Or, we can design a system that deals with flights, routes, inventory, and fare classes. Also, we can build a Facebook-killer system with friends, connections, blog posts ...