Entity-Relationship Diagram (ERD)

This ERD sample was redesigned from the Wikimedia Commons file: WordPress file-reference ERD.svg. [commons.wikimedia.org/ wiki/ File:WordPress_ file-reference_ ERD.svg]
"WordPress is a MySQL-backed blogging platform in which uploaded files are saved to a user-configurable uploads directory. Files in this directory can be organised into a number of different subdirectory structures (by default, named by year and month) under wp-content/ uploads/ in the installation directory. Files are accessed directly by the web server (and not read/ written via the application). Each uploaded file has a single row in the posts table (which may or may not be linked to an actual post row via the post_ parent key). The post_ type column of this row has a value of 'attachment'. Rows in the postmeta table are linked to this row. Where the meta_ key column of postmeta is '_ wp_ attached_ file', the meta_ value column is a filename, relative to the WP upload directory." [Web application file-reference methods. Wikiversity]
The ERD example "WordPress file-reference ERD" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Entity-Relationship Diagram (ERD) solution from the Software Development area of ConceptDraw Solution Park.