durusmail: durus-users: Re: OODB vs SQL
OODB basics
2005-10-08
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Re: OODB basics
2005-10-11
OODB vs SQL
2005-10-09
2005-10-09
2005-10-09
Re: OODB vs SQL
2005-10-10
Re: OODB vs SQL
2005-10-10
OT: Durus
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Re: OODB vs SQL
2005-10-11
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Demo application [was: Re: [Durus-users] Re: OODB vs SQL]
2005-10-13
Re: OODB vs SQL
2005-10-11
Durus basics
2005-10-09
2005-10-09
2005-10-10
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2005-10-10
2005-10-13
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2005-10-13
Re: OODB basics
2005-10-13
Re: OODB vs SQL
Michael Watkins
2005-10-12
* mario ruggier wrote [2005-10-12 08:40:43 +0200]:
> So, seeing your mail now, it seems you have already moved the files. I
> would also be interested to make a little test application with that
> data sample... If you do not mind, can you send me the links again,
> either here or privately?

I've put the files back Mario - have at them!

My import is still running... hours later and a 3GB durus file so far. I
rather hoped it would be done by 2GB, but my memory remembers a 20GB
number... It may be that the resulting ZODB was 20GB, after creating objects
based on  600mb of fairly simple raw data.

Unfortunately I put a commit in the wrong part of my loop, so every 500
records (of 13 million) a commit is being done... silly me.

> Patrick, could this be the basis of a comparison between various
> implementation scenarios? It is rather relational in nature though...  if
> we define what the test application should do, then whoever wants can
> implement the test to those speces.

This example as described so far is really so simple and trivial, except for
the volume of data. However it could be made somewhat more complex:

Symbols trade on Exchanges, Exchanges are frequently in different Countries
with different Currencies. Symbols have different Aliases depending on who
the data provider is (i.e. Reuters, Bloomberg, Yahoo, eSignal, DTN, etc all
may have a different symbol for the "Dow 30 Industrials Index").

Symbols belong to Indexes - collections of similar securities, arranged
either by Sector or by Style (large cap, mid cap, small cap etc) or by
Geography (emerging markets, US and other country indexes).

Some Symbols might be "calculated" symbols, in that their end of day values
are as a result of some computation; indexes are a simple example of this -
all symbols from the NYSE exchange could be summed in such a way to create a
composite index. Another example of a calculated index would be to determine
how many symbols hit new 52 week highs for the trading session being
examined, and store that data as "quotes" such that it can be plotted and
analysed. Or calculate how many symbols are trending up, trending down, and
not trending at all.

Quote records are an indication of what price was at the end of the trading
session; but specific events such as Splits change what the meaning of past
data is, particularly if one needs a continuous split-adjusted set of data.

etc...

eeep, its time for sleep, but I think I'll first interrupt this durus import
and see how it behaves...

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