Announcing support for composite primary & unique keys, as well as composite indexes comprising of multiple columns.
We're really excited for this one! To be honest, this took much longer than we'd like. What you're seeing is actually our 3rd-rebuild of the feature since we really wanted to nail the UX, by providing this additional functionality without compromising the minimal uncluttered feel of both the editor and canvas.
Also, the specified composite key/index supports ordering of the columns within. In most cases order won't matter, but in those few instances where it does for your app, it's good to know that your covered.
Let us know what you think, if you see anyway this can be improved further.