[fdo-internals] RE: [mapguide-internals] FDO RFC 43 - Standard
FDO Class Naming Conventions
Zac Spitzer
zac.spitzer at gmail.com
Wed Oct 28 21:21:05 EDT 2009
sounds like another RFC ?
On Thu, Oct 29, 2009 at 1:04 AM, Orest Halustchak <
orest.halustchak at autodesk.com> wrote:
> Hi,
>
>
>
> I’d also like to add a comment about something that Haris said in a
> separate reply.
>
>
>
> Ø Perhaps, providers could return additional info about names of newly
> created classes.
>
>
>
> I think that’s a good idea, maybe a way for ApplySchema to return
> information about anything that was changed from the user’s input.
>
>
>
> Thanks,
>
> Orest.
>
>
>
> *From:* fdo-internals-bounces at lists.osgeo.org [mailto:
> fdo-internals-bounces at lists.osgeo.org] *On Behalf Of *Orest Halustchak
> *Sent:* Wednesday, October 28, 2009 9:39 AM
>
> *To:* FDO Internals Mail List
> *Subject:* RE: [fdo-internals] RE: [mapguide-internals] FDO RFC 43 -
> Standard FDO Class Naming Conventions
>
>
>
> Hi Zac,
>
>
>
> FDO does have a concept of datastore. There are FDO commands to create,
> destroy, and list datastores. A datastore is also what you open with the
> connection command. It plays a role. My example is meant to show a case of
> two separate FDO datastores that for an rdbms are managed by one rdbms
> server.
>
>
>
> Thanks,
>
> Orest.
>
>
>
> *From:* fdo-internals-bounces at lists.osgeo.org [mailto:
> fdo-internals-bounces at lists.osgeo.org] *On Behalf Of *Zac Spitzer
> *Sent:* Wednesday, October 28, 2009 9:15 AM
> *To:* FDO Internals Mail List
> *Subject:* Re: [fdo-internals] RE: [mapguide-internals] FDO RFC 43 -
> Standard FDO Class Naming Conventions
>
>
>
> inline
>
> On Wed, Oct 28, 2009 at 11:56 PM, Orest Halustchak <
> orest.halustchak at autodesk.com> wrote:
>
> Hi,
>
> Note that there is another qualifier that should be taken into account in
> these discussions and that is the datastore name. There are really three
> levels of qualification: datastore name, schema name, class name. So, cases
> where it is suggested to use the file name as the schema name, if the file
> name is already used for the datastore name, it doesn't have to be used
> again for the schema name.
>
>
> My understanding is that FDO has no concept of datastore, it starts with
> schema's
>
> datastore is defined at the FDO connection level, why squeeze three levels
> into
> a two tier structure?
>
>
>
> An issue with rdbms is that some such as SQL Server include the three
> levels of database, schema, and table. Others such as Oracle do not. So in
> the Oracle case if we map the datastore name to the Oracle user/schema, then
> we should not also use Oracle user/schema for FDO schema.
>
> Consider this example.
> FDO Datastore = CityOfNewYork
> FDO Schema = LandBase
> Class = Parcel
> Class = Road
> FDO Schema = Water
> Class = Pipe
> Class = Valve
> FDO Schema = Gas
> Class = Pipe
>
> FDO Datastore = CityOfAlbany
> Same schemas and classes
>
> We don't want to mix up the parcels from CityOfNewYork with the parcles
> from CityOfAlbany, those should be in separate tables. Having the Oracle
> schema name as LandBase, Water, and Gas doesn't handle this.
>
>
> but that is a problem already solved when you follow the other way other
> database access layers work????
>
> based on the connection details, either by specifying a datastore, or not
> Pipe would only be accessible if it was the default for the user or the for
>
> specified datastore. There is a implied concept of the default schema?
>
> if there's no default and two schemas means there are no schema less tables
>
> to enumerate
>
> This is how databases normally work in my experience which is all I'm
> trying
> to suggest with this RFC.
>
> Also, about the ~ColumnName convention being used for geometry columns,
> note that FDO does allow more than one geometry column per class with one
> flagged as the main geometry. I wouldn't want to require that these have to
> be exposed as separate feature classes.
>
>
>
>
>
>
> Thanks,
> Orest.
>
>
> -----Original Message-----
> From: fdo-internals-bounces at lists.osgeo.org [mailto:
> fdo-internals-bounces at lists.osgeo.org] On Behalf Of Haris Kurtagic
> Sent: Wednesday, October 28, 2009 6:07 AM
> To: 'FDO Internals Mail List'
> Subject: [fdo-internals] RE: [mapguide-internals] FDO RFC 43 - Standard FDO
> Class Naming Conventions
>
> there is another important case which is not covered in RFC.
> Same table name in multiple schemas. Also, how to not mess up when users
> logs using different credentials.
>
> One way to solve that could be to always use rdbms schema name as fdo
> schema
> name.
>
> I believe it is absolutely necessary that application using FDO to access
> rdbms can be sure exactly which table and column it is accessing.
> Because what FDO provider sees when connects to rdbms can change regarding
> which credentials are used to connect to rdbms. That menas that on same
> database it can see only one table, or two tables (same name) in two
> schemas
> or even one or more geometry columns in table.
>
> I am not keen on current naming in King.Oracle with this ~ sign, but I am
> very pleased that when using King.Oracle and FDO class trough it, I know
> every time exactly which Oracle schema, table and column I am hitting.
>
>
>
>
> Just when wanted to finish something else from RFC:
> "Class names for databases are normally tablename, unless qualified which
> then has ~COLUMN_NAME appended. (if the are multiple geometries, FDO
> requires to know which one is the identifier)"
>
> In King.Oracle ~COLUMN_NAME is appened to make sure resulting name would be
> unique. Which actuall oracle column is used is not parsed from name of
> class
> but it is kept inside provider. ~COLUMN_NAME could be anything.
>
>
> Haris
>
> -----Original Message-----
> From: mapguide-internals-bounces at lists.osgeo.org
> [mailto:mapguide-internals-bounces at lists.osgeo.org] On Behalf Of Zac
> Spitzer
> Sent: Wednesday, October 28, 2009 9:45 AM
> To: FDO Internals Mail List; MapGuide Internals Mail List
> Subject: [mapguide-internals] FDO RFC 43 - Standard FDO Class Naming
> Conventions
>
> I have posted RFC 43 for review
>
> http://trac.osgeo.org/fdo/wiki/FDORfc43
>
> --
> Zac Spitzer -
> http://zacster.blogspot.com
> +61 405 847 168
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>
>
> --
> Zac Spitzer -
> http://zacster.blogspot.com
> +61 405 847 168
>
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--
Zac Spitzer -
http://zacster.blogspot.com
+61 405 847 168
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