= FDO RFC 43 - Standard FDO Class Naming Conventions  =

This page contains a request for comments document (RFC) for the FDO Open Source project.  
More FDO RFCs can be found on the [wiki:FDORfcs RFCs] page.

== Status == 
 
||RFC Template Version||(1.0)|| 
||Submission Date||(Date/Time submitted)||
||Last Modified||Zac Spitzer [[Timestamp]]||
||Author||Zac Spitzer||
||RFC Status||(draft)||
||Implementation Status||(pending)||
||Proposed Milestone||(3.5)||
||Assigned PSC guide(s)||(when determined)||
||'''Voting History'''||(vote date)||
 
== Overview ==

"Schema

In RDBMS terms, a Schema is a collection of tables, indexes,
views, etc. in a database. Feature and RDBMS schemas do not correspond 1:1.

A Feature Schema may be stored in different RDBMS schemas and an RDBMS schema
might be composed of multiple logical schemas."

[http://fdo.osgeo.org/glossary.html]

As a result of this loose definition we have no simple standard for schema and class naming across providers.

== Motivation ==

FDO is meant to be a transparent data access layer, however, currently providers inject information into the 
FDO class names which make the same data in different datastores have different names.

Here are some examples of different schema & class names currently in use in FDO

 * OSGEO.SHP reports Default:shpfilename
 * OSGEO.Gdal reports default:default
 * KingOracle reports KingOra:ZAC~BUILDINGOUTLINES~SHPGEOM
 * OSGEO.OGR reports OGRSchema:BUILDING
 * MySql reports Fdoreports:aquifer_property

SDF reports what ever was set as the schema name

There is no predicable the pattern?

There is no need to inject provider names into the naming.

The PostGIS provider has already adopted this approach following this mailing list discussion[[BR]]
[http://www.nabble.com/Is-there-a-Feature-class-naming-convention-to15021175s18162.html#a15021175][[BR]]
[http://trac.osgeo.org/fdo/ticket/310][[BR]]

== Proposed Solution ==

 * Providers which don't support multiple schemas, should report an empty schema, all their content lives in that single schema ( ie was default).
 * Providers which have native schemas with multiple real schemas, should represent those available schemas to GetSchemas unless over-ridden
in the connection string or by custom mappings.
 * The tables in the user schema are listed in empty schema (default) conceptually potentially twice.
 * 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)
 * Class names for file based providers is based on their file name as current
 * Therefore, The empty schema ":watercourses" could be also just "watercourses"

which would result in

 * OSGEO.SHP returns filename
 * OSGEO.Gdal returns filename
 * KingOracle returns schema:tablename or if connected as "schema" then just tablename
 * OSGEO.OGR returns filename
 * MySql returns schema:tablename or if connected as "schema" then just tablename
 * SDF still returns what ever you like as a schema name

== Implications ==

Each Provider would need to be updated to match the updated standard conventions

== Test Plan ==

Expose the Sheboygan dataset via FDO matching the standard conventions

== Funding/Resources ==

TBD

== Links ==

[http://zacster.blogspot.com/2008/08/some-ponderings-on-fdo-schemas.html][[BR]]
[http://geospatial.blogs.com/geospatial/access_to_spatial_data/][[BR]]
[http://n2.nabble.com/Standardising-FDO-Schema-s-td2051792i20.html][[BR]]