1. This trigger is from Figure 16.2 ofthe text. Copy and run this trigger so it is created in the apdatabase. You can run the UPDATE below to test it. Notice twothings. The error message appears as a pink screen just like asyntax error would. Also, if you then query the invoices table, theUPDATE statement did not execute. The trigger prevented theerroneous UPDATE from changing the data.
DELIMITER //
CREATE TRIGGERinvoices_before_update
BEFOREUPDATE ON invoices
FOREACH ROW
BEGIN
DECLARE sum_line_item_amount DECIMAL(9,2);
SELECTSUM(line_item_amount)
INTO sum_line_item_amount
FROMinvoice_line_items
WHEREinvoice_id = NEW.invoice_id;
OR
OR