Really nice piece of work.
Your module looks quite promising.
There are few things you may wish to fix for your module. There are some glithes that make this module unusable on postgreSQL. First, you should mark table field as reference only if it refences to a key (apps_cartesi_prod2ord -> quantity) and you should also avoid data duplication.
Secondly, char ` is used only in mySQL (like in Cartesi_0.php, line 43).
Last thing that causes problem is LIMIT clause. PostgreSQL uses LIMIT x OFFSET y. To create universal query use DB::SelectLimit($sql, $numrows, $offset);
Also, you may want to add some more navigation buttons, like back buttons.
Oh, and one more thing: you can place this image, Apps_Cartesi.png in folder Apps/Cartesi/theme as default.png and add this line to installation method:
and this line to uninstallation method:
With this, your image will be automatically placed in data/Base/Theme/templates/ folder as Apps_Cartesi__default.png
Thank you for this contribution, we really appreciate it! Keep up the good work.