The distinction between tools and applications is murky. For example, developers use simple databases (such as a file containing a list of important values) all the time as tools. However a full-blown database is usually thought of as an application or software in its own right. For many years, computer-assisted software engineering (CASE) tools were sought after. Successful tools have proven elusive. In one sense, CASE tools emphasized design and architecture support, such as for UML. But the most successful of these tools are IDEs.