You should Use these tables to help you category. (catNo, catogery Name), Items(itemNo, ItemName, Price, total _quantity, catNo), By using PL/SQL : Create procedure to add new item(ItemName,Price,total_quantity, category name) which use validation method checkExistingitem using exception to validate item name if its not exists before, then add this category and generate the item number automatically using database trigger, Note create method getCatgeoryNo(category name) to return category number to be used when item is added, this method will return 1 if category name not exists, and the procedure addltem will display message that one item record has been added or this category not exists or this item is exists before