Basically, I am to create a point_of_sale simple GUI. I have to JOIN the POS_SALE_LINE table with ITEM_ODBC_IMPORT table.
The shop assistant, using a bar code scanner, will EITHER scan the internal company's barcode (not an EAN or any ISO standard, simply the conversion of a textline into a barcode) OR the international EAN13 code onto the product.
PROBLEM_1: the products not always have an EAN13. Therefor there are ITEM_COD without any EAN
PROBLEM_2: sometimes the products have more than one EAN13 associated. Therefor there are more EAN for each ITEM_COD
PROBLEM_3: how to enable the shop assistant to pick the right line with one single scanning? Either on the internal code OR on the EAN13 when available.
Ideally, how to make a field that will get the text string from the bar code scanner, and will thereafter JOIN_UNION of EAN (any available for the each ITEM_COD) or ITEM_COD.