Disclosure: I build Schemity , a desktop ERD tool - this post is from our blog and uses it for the examples. TL;DR: The database has a built-in place to document a column - COMMENT ON COLUMN in PostgreSQL, the COMMENT attribute in MySQL - and almost nobody fills it in, because a sentence of prose has to travel the same path as a schema change: a migration file, a review, a deploy. Schemity keeps field descriptions in the diagram instead, where editing one generates no SQL, reads existin...