I can see in all forms.apl.php files the variables $old_value_fieldname,
$old_value_fecha = $this->fecha;
$old_value_numero = $this->numero;
$old_value_fvence_aut = $this->fvence_aut;
$old_value_b_base0 = $this->b_base0;
Can I use these variables for take the old value of any form field in form event code ?
In MsAccess these old values are very useful when the user cancel the input or the validation of a new value fail, then I can reasign the old_value again.
Or to log any change, "old value = " . $old_value_… . "new value = " . {field}
or when update stock tables with sql :
update stock set onstok = (onstock - old_value), onstock = (onstock + new_value)
Aquiles