This is an online Entity Relationship diagram. An entity relationship (ER) diagram is a form of flowchart that shows how "entities" such as people, things, or concepts interact inside a system. ER Diagrams are most used in the disciplines of software engineering, education, and research to build or troubleshoot relational databases. They employ a predetermined collection of symbols such as rectangles, diamonds, ovals, and connecting lines to illustrate the interconnectivity of entities, relationships, and their qualities. They are also known as ERDs or ER Models. They reflect linguistic structure, with items acting as nouns and connections acting as verbs. To modify this diagram, communicate with others, and export results to different image formats, use EdrawMax's simple online diagram editor.