Hi,
Sorry for my unclear info.

I have 3 type of item, normal, serialno and matrix.

Normal Item: Item such as cann food, has a default barcode, but will has more than one barcode since the barcode from manufacturer may changed batchly. However, all transactions will be based on the default, meant even user may use different barcode to sell the same item, but user only wan to know it's qty as lumpsum.

SerialNo: Item such as handphone. Each phone has different serialno even though it is in same model. The availablity of the handphone (particular serialno) should be tracable. However, stock qty will be as lumpsum and only has ONE barcode.

Matrix: Item such as fashion/shoes. It can be differentiate with different colour/size. It has one default barcode, and each combination of colour/size will has it's own unique barcode. Stock qty for each combination must be tracable -
T-Shirt Red XL - 10
T-Shirt Red L - 05

So, howto design the tables?
Please don't hestitate to inform me if you need more info.

Thank you for your time.