On occasion, some of Brewbean's customers mistakenly leave an item out of a basket already checked out, so they create a new basket containing the missing items. However, they request that the baskets be combined so that they are not charged extra shipping. A screen has been developed to allow an employee to modify the basket id of items in the BB_BASKETITEM table to another to another existing basket to combine the baskets. A block has been constructed to support this screen and can be found at the end of this question. However, an exception needs to be added to trap the situation in which an invalid basket id is entered for the original basket. In this case, the UPDATE affects no rows but does not raise an Oracle error. The handler should display a message stating "invalid original basket id". Use a host variable named G_OLD with a value of 30 and a host variable named G_NEW with a value of 4 to provide the values to the block. First verify that no item rows exist in the BB_BASKETITEM table with a basket id of 30.
BEGIN UPDATE bb_basketitem SET idBasket = :g_new WHERE idBasket = :g_old; END; /