[jasonwatkinspdx]

DB storage is a lot more sophisticated than what you were taught.

Most databases use Slotted Pages to organize storage. Pages are fixed size and numbered by their offset within the database file. The page header contains the number of rows, followed by an array of offsets for individual rows within the page. Rows themselves generally are stored at the end of the page filling downwards. The storage engine can move around rows in arbitrary ways to consolidate free space.

Fundamentally there's no connection between SQL schema order and how table storage is organized on disk. For example in a column store there's often no contiguous row stored anywhere, instead there's just separate indexes per column.

[lsaferite]

That would seem like an argument in favor of allowing column reordering.