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Hello,
The reason why fundamental data implemented in AB are current only are as follows:
a)
Yahoo nor any other free source of fundamental data does not provide historical values
for majority of fields. The idea behind new fundamental data functionality in AB
was to couple it with a method to actually RETRIEVE this data automatically.
Since only current values are available from Yahoo, so there was no point in bumping
database size for functionality that would be left unused for most people
b)
The idea was to help scanning (stock picks) based on fundamentals only.
Backtesting systems based on fundamentals requires 20+ years of data to make any sense
(because they change so infrequently - otherwise you would have too small data sample to make results resonable).
Since AB target user base is not really that long-term investors, and there are no
free data (see a)) it made even less sense
c)
The idea was to add functionality without growing database - AB database format was prepared
for fundamentals since day 1 (May 1995) but there were no method to access these fields.
As to SQL advantages: using external database
a) you have unlimited number of custom fields of any type
b) you can store less frequent data effectively (if you have quarterly data using external database
you would store just 4 records per year)
c) you can access these data from external ODBC-aware programs
Overall the general idea of AmiBroker is as follows:
a) core functionality is provided internally + means to easy update from FREE sources
b) extra functionality is provided by means of plugins / external sources / scripts
This design ensures that
a) AmiBroker is not bloated with stuff that almost no one is using
b) AmiBroker delivers flexibility allowing individuals to extend its functionality. And here you are limited only by your
imagination.
Best regards,
Tomasz Janeczko
amibroker.com
----- Original Message -----
From: "treliff" <treliff@xxxxxxxxx>
To: <amibroker@xxxxxxxxxxxxxxx>
Sent: Sunday, July 23, 2006 9:41 AM
Subject: [amibroker] Re: On Fundamental data import
> Being a long-time artificial ticker-er myself (and an absolute non-
> programmer) I think one disadvantage of this method is that, assuming
> a daily data base, we are creating arrays with many, many duplicate
> values. For example an array containing EPS (in one of the OHLCVI
> fields) would only change about 4 times a year; during 3 consecutive
> months we are stuffing this array with the same value.
>
> I can imagine this simply puts a lot of strain on the AB database.
> And for example 30 fundamentals divided among 5 arti-tickers for each
> stock increases a 2,000 stock database to 10,000 "stocks".
>
> I am just assuming this because if not, then why would TJ not have
> implemented the new fundamentals as arrays, in this case not with 6
> OHLCVI datafields but with one single datafield, so indeed daily (or
> bulk ASCII) imported (funda) values would build a historical database
> completely within AB similar to price data.
>
> I remember though having read requests for "custom arrays" in deep
> historical depths of the message board archives, so there must be a
> good reason why these were never implemented.
>
> But just as dbirru I'd be very interested to know if SQL will have a
> serious advantage over artificial tickers. I am absolutely ignorant
> about SQL so will this be worth digging into?
>
> Thanks very much for advice from TJ or other experts.
>
> -treliff
>
> --- In amibroker@xxxxxxxxxxxxxxx, "Michael.S.G." <OzFalconAB@xxx>
> wrote:
>>
>> If you import your fundamental data into artificial tickers (eg
>> Code-FndData) to create a historical database of Fnd Data,
>> Then it appears as though these new additions have little benefit
> to us.
>> I do the same thing, And reference with Foreign.
>>
>> I find it quite convenient to access historical fundamental data
>> "within" amibroker, As opposed to accessing some external DB.
>> I mean, AmiBroker itself is a DB. So why make things more
> complicated
>> by accessing external db's. (Just my thoughts).
>> Im not sure it would be any quicker using external database as
> opposed
>> to AB inbuilt Foreign function.
>>
>> The only gripe I have, And I dare say it would be the same if the
> data
>> was stored in an external DB - Is the inability of the
>> shiftx or ref() functions to access Future Foreign data (As in
> reference
>> to the Selected ticker).
>>
>> Here is example of charting historical fundamental data accesed via
> an
>> artificial (foriegn) ticker.
>>
>>
>> dbirru wrote:
>> >
>> > Is the new fundamental import faster compared to doing it via the
> old
>> > way of the ascii importer?
>> >
>> > I used to import fundamental data using artifical ticker and the
> ascii
>> > importer (using the 9 or so available fields). In AFL, this
> requires
>> > using the foreign function. I find that this method slows down
>> > exploration considerably since for every ticker a corresponding
>> > ticker need to be read. The values are also stored in an array.
>> >
>> > The latest ascii importer contains additional fields to ease
> improting
>> > of fundamental data. Does this new way of improting fundamental
> data
>> > make exploration considerably faster? If the dat astructure is
>> > different, then I expect it may be faster. But, I don't know the
> data
>> > structure. Thus, I asked before I try it and 'corrupt' my
> database if
>> > it does not offer an advantage.
>> >
>> > Thanks.
>> >
>> > __
>>
>
>
>
>
>
>
>
> Please note that this group is for discussion between users only.
>
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