We need to have contacts with just a name: we need to assign
freelancer’s quote as expense linked the government, but of course we
do not have a phone or email for that “contact”, much less a VATIN or
other tax details.
It is also interesting for other expenses-only contacts to not have to
input all tax details, as we may not need to invoice then, thus are
useless for us, but sometimes it might be interesting to have them,
“just in case”.
Of course, i did not want to make nullable any of the tax details
required to generate an invoice, otherwise we could allow illegal
invoices. Therefore, that data had to go in a different relation,
and invoice’s foreign key update to point to that relation, not just
customer, or we would again be able to create invalid invoices.
We replaced the contact’s trade name with just name, because we do not
need _three_ names for a contact, but we _do_ need two: the one we use
to refer to them and the business name for tax purposes.
The new contact_phone, contact_web, and contact_email relations could be
simply a nullable field, but i did not see the point, since there are
not that many instances where i need any of this data.
Now company.taxDetailsForm is no longer “the same as contactForm with
some extra fields”, because i have to add a check whether the user needs
to invoice the contact, to check that the required values are there.
I have an additional problem with the contact form when not using
JavaScript: i must set the required field to all tax details fields to
avoid the “(optional)” suffix, and because they _are_ required when
that checkbox is enabled, but i can not set them optional when the check
is unchecked. My solution for now is to ignore the form validation,
and later i will add some JavaScript that adds the validation again,
so it will work in all cases.
We are going to allow invoices with products that are not (yet) inserted
into the products table.
We always allowed to have products in invoices with a totally different
name, description, price, and whatnot, but until now we had the product
id in these invoice lines for statistics purposes.
However, Oriol raised the concern that this requires for the products
to be inserted before we can create an invoice with them, and we do not
plan to have a “create product while invoicing” feature, thus it would
mean that people would need to cancel the new invoice, create the new
product, and then start the invoice again from scratch.
The compromise is to allow products in the invoice that do not have a
product_id, meaning that at the time the invoice was created they were
not (yet) in the products table. Oriol sees this stop-invoice-create-
product issue more important than the accurate statistics of product
sales, as it will probably be only one or two units off, anyway.
I did not want to allow NULL values to the invoice product’s product_id
field, because NULL means “dunno” instead of “no product”, so i had to
split that field to a separate table that relates an invoice product
with a registered product.
It all started when i wanted to try to filter invoices by multiple tags
using an “AND”, instead of “OR” as it was doing until now. But
something felt off and seemed to me that i was doing thing much more
complex than needed, all to be able to list the tags as a suggestion
in the input field—which i am not doing yet.
I found this article series[0] exploring different approaches for
tagging, which includes the one i was using, and comparing their
performance. I have not actually tested it, but it seems that i have
chosen the worst option, in both query time and storage.
I attempted to try using an array attribute to each table, which is more
or less the same they did in the articles but without using a separate
relation for tags, and i found out that all the queries were way easier
to write, and needed two joins less, so it was a no-brainer.
[0]: http://www.databasesoup.com/2015/01/tag-all-things.html
Initially, this field was meant to be left almost always blank, except
for when we deleted invoiced and had to “replace” its number with a new
invoice; using the automatic numbering in this cas would not “fill in”
the missing number in the sequence.
However, we decide to not allow removing invoicer not edit their
numbers, therefore, if everything goes as planned, there should not be
any gap in the sequence, and that field is rendered useless.
Oriol suggested making it a read-only field, both for new and edit
forms, but i do not think it makes sense to have a field if you can not
edit it at all, specially in the new invoice dialog, where it would
always be blank. In the edit form we already show the number in the
title and breadcrumbs, thus no need for the read-only field as
reference.
I still keep a Number member to the form struct, but is now a string
(kind of “a read-only field”, in a way) and just to be written in the
title or breadcrumbs. I did not like the idea of adding a new SQL
query just for that value.
I had to use a deferrable foreign key because the payment methods have
a reference to the company, and the company now a circular reference to
payment method.
We want to show the percentage of the tax as columns in the invoice,
but until now it was not possible to have a single VAT column when
products have different VAT (e.g., 4 % and 10 %), because, as far
as the application is concerned, these where ”different taxes”. We
also think it would be hard later on to compute the tax due to the
government.
So, tax classes is just a taxonomy to be able to have different names
and rates for the same type of tax, mostly VAT and retention in our
case.
jordi fita mas