[fdo-dev] SHP provider

[Pierre Dalcourt]

Hi,

Its possible for SHP Provider to support more FDO data types.
However, you have to consider SHP/DBF limitations.  DBF only supports a
few types: numeric (stored in ascii format), string, blob, date, and
boolean.  To distinguish between int16/int32/int64 for example, you
would need to store some metadata indicating which of these types the
column represents.  There is (theoretically) no room for custom metadata
in the DBF/SHP files, although perhaps there is a way to hack around
that.  You would have to store metadata in a separate file.  There is
already code to store such information in an xml file, but it is
currently (mostly) disabled for technical reasons.  There are also other
considerations, such as the fact that since DBF stores numbers in ascii
format while FDO represents numbers in binary format, the range of
numbers you can store in FDO or DBF will never match up exactly.  Also,
you have to consider that applications outside your own will be
editing/creating SHP/DBF files which might break any artificial numeric
limits you impose since they are not aware of your metadata.

Pierre

-----Original Message-----
From: Haris Kurtagic [mailto:haris at sl-king.com] 
Sent: October 29, 2006 11:56 AM
To: dev at fdo.osgeo.org
Subject: RE: [fdo-dev] SHP provider


As a meter a fact it is very simple, basically for shp provider data
store is the folder.
Apply schema will create shp files in folder (data store).

Anyhow I agree that this command should be implemented, it is important
to try to keep consistency across providers, to have a common level of
functionality as high as possible.

Haris

-----Original Message-----
From: Mateusz Loskot [mailto:mateusz at loskot.net] 
Sent: Sunday, October 29, 2006 2:46 PM
To: dev at fdo.osgeo.org
Subject: Re: [fdo-dev] SHP provider

Haris Kurtagic wrote:
> Hi,
> 
> Shape provider is suporting very limited range of fdo data type's.
> 
> I believe it is small change to add double,single int32,int64,..
> 
> Fdo shp provider is open for contributations ?

Haris, I'd like to join your question.
I'm also wondering the reason CreateDataStore command has not been
implemented yet.
Theoretically, it seems as not a big challenge, but I suppose there are
some details which I can't see but which make it tricky.
I'd be thankful for some comments from SHP provider developer(s).

Cheers
--
Mateusz Loskot
http://mateusz.loskot.net

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