[fdo-users] Is there a Feature class naming convention

[Orest Halustchak]

There are two scenarios.

If the provider is accessing an existing schema, e.g. not created by fdo, then the provider decides how to map the table / file to a class and schema. The main thing is that the mapping is unique and unambiguous as Traian said.

The other scenario is if a new class is defined via fdo. In this case, the caller is specifying an explicit schema name and class name. A describe of that class then should come back with the same names as long as the input names were valid (FdoISchemaCapabilities has methods to get information about valid names such as name size limits and valid characters).

Thanks,
Orest.

-----Original Message-----
From: fdo-users-bounces at lists.osgeo.org [mailto:fdo-users-bounces at lists.osgeo.org] On Behalf Of Traian Stanev
Sent: Tuesday, January 22, 2008 12:11 PM
To: fdo-users at lists.osgeo.org
Subject: RE: [fdo-users] Is there a Feature class naming convention


>From what I vaguely remember (and I wrote that code in the OGR provider), some OGRLayers (which correspond to FDO feature classes in the OGR provider) came back with a . in the name. Basically the OGR Layer name was of the form "TABLE.CLASS" or something like that, and that whole string corresponds to one feature class. Since "." was not a valid character for FDO, I replaced it by ~ in such cases.

Note that all of these feature classes are expressed as belonging to a single OGR connection schema called OGRSchema. So you can access the feature class "TABLE.LAYER" using:

OGRSchema:TABLE~LAYER

The OGR provider takes care of this transparently when going back to the database and will convert that back to TABLE.LAYER.

As long as you are using the FDO API to do all this, it will work fine and complies with the FDO naming conventions. The class name is not ambiguous and the provider knows exactly what to do as long as you use that class name.


What you are really questioning here is that the feature class name as reported by the FDO provider does not match the native table name in the database. Why is this a bug?


Traian




> -----Original Message-----
> From: fdo-users-bounces at lists.osgeo.org [mailto:fdo-users-
> bounces at lists.osgeo.org] On Behalf Of Bruno Scott
> Sent: Tuesday, January 22, 2008 11:55 AM
> To: fdo-users at lists.osgeo.org
> Subject: Re: [fdo-users] Is there a Feature class naming convention
>
>
> When i query the className against the OGR PostGIS
> it returns : MySchema~MyTable
>
> When i query the className against the King.Oracle
> it returns : MySchema~MyTable~myGeometryColumn
>
> So if classname should be "MyTable" and fully qualified name
> "MySchema:MyTable"
> Can we consider this as a bug in these 2 providers?
>
>
>
>
> Orest Halustchak wrote:
> >
> > I'm not sure why these providers would change the class names this
> way.
> >
> > From FDO you can ask for class name and fully qualified class name
> > separately so there should be no need to change the class name this
> way.
> > Class name should come back as "MyFeatureClass" and fully qualified
> class
> > name should come back as "MySchema:MyFeatureClass".
> >
> > Thanks,
> > Orest.
> >
> > ------Original Message------
> > From: Bruno Scott
> > To: fdo-users at lists.osgeo.org
> > ReplyTo: FDO Users Mail List
> > Sent: Jan 22, 2008 10:33 AM
> > Subject: [fdo-users] Is there a Feature class naming convention
> >
> >
> > When we create a feature class, let say using the MySQL provider we
> give a
> > feature class name example: "MyFeatureClass"
> > and when we query it we use the same "MyFeatureClass"
> > This is fine...
> >
> > With the PostGIS provider, we create the feature with a name like
> > "MyFeatureClass"
> > but we query with a different name example "MySchema.MyFeatureClass"
> >
> > We have this same problem with the King.Oracle provider
> >
> > When you have an application that uses any FDO RDBMS provider, it
> makes
> > things very difficult to handle.
> > We need to hardcode
> > "if provider == PostGis" then
> > "if provider == KingOracle then
> > ...
> >
> > And it is a bit against the FDO philosophy, a single language to
> address
> > the
> > same way any spatial database,file
> >
> >
> > It there a reason for that different naming?
> >
> > Bruno Scott
> >
> >
> >
> >
> > --
> > View this message in context:
> > http://www.nabble.com/Is-there-a-Feature-class-naming-convention-
> tp15021175s18162p15021175.html
> > Sent from the fdo-users mailing list archive at Nabble.com.
> >
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> class-naming-convention-tp15021175s18162p15023058.html
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