The screenshot you show comes from WWW SQL DesignerWWW SQL Designer:
- free and open source (New BSD License)
- online demo
- retrieve (import) schema from existing database.
- cross-platform (web application)
Description from the website:
This tool allows you to draw and create database schemas (E-R diagrams) directly in browser, without the need for any external programs (flash). You only need JavaScript enabled. The Designer works perfectly in Mozillas (Firefox, Seamonkey), Internet Explorers (6, 7, 8), Safari and Operas. Konqueror works, but the experience is limited.
Many database features are supported, such as keys, foreign key constraints, comments and indexes. You can either save your design (for further loading & modifications), print it or export as SQL script. It is possible to retrieve (import) schema from existing database.