I wonder the database structure behind airtable-like flexible data apps. I suppose they would create databases and tables on the fly to increase performance - or maybe they just use unstructured (or flexibly structured) databases like mongodb?
"First off, we're huge fans of both Meteor and Asana. I spoke with Geoff @ Meteor a couple years ago when we were first starting to build out the Airtable product and was very impressed by their approach and vision.
We've closely followed the developer blogs of both those projects (and in Meteor's case, their source code). With those learnings, we built our own realtime database engine that supports relational data (which Meteor doesn't yet support) and also some other major features like the ability to undo any user action out of order (like git revert), which is necessary to support undo in a multi-user context (because the last thing that you did may not be the last change globally if other people are concurrently making changes). Undo is a particularly challenging feature to implement in a structured relational database context, because it can't be reduced to a set of simplistic character insertion operations as is the case for a google word doc, or a spreadsheet (which is a simple 2d array of values without type constraints, foreign key relations, etc)."
