[Qgis-developer] Oracle provider tests

Jürgen E. Fischer jef at norbit.de
Fri Jun 7 07:39:13 PDT 2013


Hi Andreas,

On Fri, 07. Jun 2013 at 16:09:25 +0200, Andreas Neumann wrote:
> If yes, you have to choose the geometry type and the primary key column -
> otherwise you cannot select and add the layer. Same with Postgis, but with
> Postgis there is some good autodetection (depending on the QGIS version).

QGIS needs a specific CRS (ie. SRID) and a defined geometry type (point, line,
polygon) for each layer and offers what it finds in the database or requires to
enter what is undefined.  You can only select the lines that are fully defined.

That's very similar in the PostGIS and Oracle dialogs.  It's just that Oracle
doesn't have "standard" constraints, that limit the usable geometry types and
SRIDs in a column and therefore also doesn't have a metadata table that carries
that information, while PostGIS tables are usually quite constrainted.

So for Oracle everything except the geometry columns themselves need to be
scanned, while for PostGIS that can be taken from the metadata table in the
usual case with applied constraints.

If you create geometry column in PostGIS 2 with SRID 0 (meaning any) and type
GEOMETRY (any geometry type) the outcome might be quite similar and you get a
couple of lines for that column, each with a different combination of available
geometry type and SRID combinations in the table plus another line where you
can enter geometry types and SRIDs that you don't already have.

But the oracle provider isn't very widely used, so there are probably still
things that could use attention.


Jürgen

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