You can add a form on the page trough form module or form field plugin, then copy values from content to form fields using SD databaser plugin. You can put fields except send button ito a hidden position so that they are invisible to user.
I want to save the IDs of the selected items / products that user selects in to a table.
I used form field plugin to add a form on the content page, but I have not figured out how to use SD databaser plugin. I've tried to use SD live CCK to retrive ID of article but it dosn't work, i retrive art_title, but NO art_id...
Can you help me on how to use SD databaser plugin?
Sd databaser is not going to help here - instructions for all SD plugins are written on the product page otherwise. With SD live you need sure you actually have field you are getting value from in the content view, you can use hidden variation or place it in hidden position.
Probably your problem is that you are trying overwrite CCK_ID and ART_ID field in the form - those values are automatically assigned and can't be changed. You need to store those values in another field (or in another words you can't store to the same article from a different form)