[GNC] Import CSV Multi-currency

Sat Nov 24 23:46:57 EST 2018

On Sun, 2018-11-25 at 00:14 -0300, GTI .H wrote:
> Em sáb, 24 de nov de 2018 às 19:47, David Cousens <davidcousens at bigpond.com>
> escreveu:
> 
> > GTI,
> > 
> > David Carlson's description is actually more correct in accounting terms
> > and
> > the way GnuCash actually works. This is a double entry accounting system
> > which means that all transactions have at least two splits.
> > 
> > In the case of a currency conversion transaction, the transfer of asset
> > value is between the account in the initial currency and a separate account
> > in the final currency, so there is at least a split for each account. (If
> > there are currency conversion fees involved that are not incorporated in
> > the
> > price/currency conversion information for example you could have additional
> > splits to account for this.)
> > 
> 
> heheheh!
> Without an official definition of "split", it seems that each of us has
> created its own definition!

There is an official definition of what a split is. See 
https://www.gnucash.org/docs/v3/C/gnucash-guide/txns-register-oview.html and the following section 
https://www.gnucash.org/docs/v3/C/gnucash-guide/txns-registers-txntypes.html and also 
https://www.gnucash.org/docs/v3/C/gnucash-guide/basics-accounting1.html. I am not creating my understanding of splits in
transactions out of thin air. I have a Masters degree in accounting and my description is in accordance with accounting
practice world wide as well as the implementation within GnuCash.

> 
> According to your definition, there is no single line transaction in
> GnuCash.
> 
> For me what you described was not a split but a balancing act.
> For me, you can balance by creating splits or without creating splits.

You may need to look far more deeply at the underlying principles behind double entry accounting which is implemented in
GnuCash if you think this is the case.
> 
> 
> > Each of the two (or more)  "splits" which constitutes the transaction only
> > affects the account to which it refers. The data structures internal to
> > GnuCash maintain a separate data structure for each component of the split
> > which has a pointer to the transaction it belongs to and the transaction
> > data structure maintain pointers to all the splits which constitute that
> > transaction.
> > 
> 
> I know the data structure a bit, it is prepared to receive transactions
> with splits, but not every transaction has splits (in my definition).

Every transaction has splits and affects at least two accounts at least internally within GnuCash. Data to be imported
depending on the source may or may not have information about the second split however. In the case of a transaction
involving a currency converion that data either has to contain information about the second split or at least sufficient
information to reconstruct it. I am in the process of preparing a more detailed analysis of what is exported from a
currency conversion transaction and whether it can be reimported successfully. This will take some time, but I will post
the results in this thread when complete. 

Results so far indicate a transaction exported from an account in the main currency your books are kept in in single
line format does not contain enough information to recreate the original transaction. If the transaction is exported
from the account in the second currency to or from which conversion took place, the single line record does contain
sufficient data to reproduce the transactions, however there may be rounding errors depending on how the conversion
ratio/price was stored.
> 
> 
> > For convenience and compactness, in the register display, this is normally
> > (depending on optional choices in the preferences for the register display)
> > compacted to a single line display which can be expanded to show the full
> > structure of the transaction. That expanded structure is  more
> > representative of the way a transaction is represented internally inside
> > GnuCash.
> > 
> 
> Why do you think what you see (expanded to show the full structure of the
> transaction) is the real structure of the transaction, splitted or
> simple-line? Do you count the lines you see?
> We can create for our registers as many  views/display formats as our
> imagination allows without altering the real structure of the transaction
> and this does not necessarily show the real structure of the transaction
> only shows the data fields arranged in a standard view.

True only relevant information from the complete data structure is displayed in the register. However internally within
GnuCash there is no such thing as a single line transaction. 
> 
> As you noted GnuCash's default export format is multiline but it can also
> > export in single line format if you check the SImple Layout box in the
> > first
> > page of the wizard but this can cause a loss of information compared to the
> > multiline format.
> > 
> 
> True! This had escaped me and it seems that Price is always lost on
> single-line export.
> It seems we have bugs here too.

When you export in single line format from an account in the main currency your books are kept in there is no currency
conversion information in the record. It is however in a record exported from the "foreign currency" account that the
transaction was targeting with its second split. In principle this could be imported to recreate the record. I am still
checking out whether it can in fact be imported successfully
> 
> 
> > There is currently a problem with importing data with a currency exchange
> > even with the multilline format, which I will be reporting as a separate
> > bug. In essence for importing a currency exchange between an AUD and a USD
> > account for $100AUD to $110 USD, the importer creates the trnsaction
> > correctly in the AUD asset account and the USD asset account but it also
> > creates an Imbalance account transaction for $1000, which it should not. To
> > correct this requires deletion of the Imbalance account transaction which
> > is
> > incorrectly created on import,
> > 
> 
> Bugs, bugs, and more bugs.
> Something similar occurs in my bug report of this thread, try reproduce it
> to see.
The CSV importer was originally written primarily for importing data from sources such as banks from a single account
and probably did not envisage dealing with multicurrency transactions. The export capability is a comparatively recent
development and the whole importer is really still a work in progress as Geert pointed out. I have an interest in this
problem as I import Paypal account data with CSV and if I have purchases in a foreign currency Paypal insist on
including the currency conversion details. I currently pre-edit the file to delete this but it would be more convenient
to be able to setup a proper import of the conversion detail so i retain it.
> 
> The single line format data cannot be imported correctly at all at the
> > moment as Geert indicated in his reply. The single line exported data has a
> > separate column for the base account for the transaction and a separate
> > column for the transfer account but in the importer as it is coded at the
> > moment there is no facility to associate a transfer account to this column.
> > 
> 
> "Transfer account" is available only for single line import which only
> works for one currency, in mult-split this is replaced by "Account Name".
> 
> Geert also indicated that the main developer effort is currently directed to
> > other areas. I have had a little bit of experience with some parts of the
> > importer code although not that associated with currency/commodities to
> > data
> > so far. I will try have a look at the code area to see if I can isolate at
> > least the above problem with the multiline import which is in the
> > import-matcher I have previously looked at and fix that. I may learn enogh
> > to start looking at the single line import problems, but that will
> > certainly
> > take longer.
> > 
> 
> This will be really very good!
> If it does not start it will never end.
> 
> 
> --
> Regards
> GTI

Cheers

David Cousens
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