如何通过oracle表格验证前四位数作为字符，最后三位数作为容器编号字段中的数字
我试过以下
begin
if container_number is null then
error message;
else
for i in 1..length(:xxms_xp_shippingout_line.container_number)
v_length:=substr(:xxms_xp_shippingout_line.container_number,i,4);
v_length1:=substr(:xxms_xp_shippingout_line.container_number,i,5);
loop
if v_length is not between 'A' and 'Z' then
error message;
if v_length1 is not between '0' and '9'
error message;
end if;
end if;
end if;
end;