Sub-issue of #9, depends on #9a (shared helpers) ``` pub fn update_book(conn, id, title, author, status) -> Result(Book, AppError) ``` - `UPDATE books SET title=$1, author=$2, status=$3 WHERE id=$4 RETURNING id, title, author, status` - Empty rows → `Error(NotFound)`
Sub-issue of #9, depends on #9a (shared helpers)
UPDATE books SET title=$1, author=$2, status=$3 WHERE id=$4 RETURNING id, title, author, statusError(NotFound)