Michael,
I think most of our PostGIs/PostgreSQL code has been "abandoned" in
some sense. I don't know that you will be able to find an active
developer that is very familiar with this code. I think any
improvements you could make to this code would be welcome.
The Sunburned Surveyor
On 5/27/07, Stefan Steiniger <[EMAIL PROTECTED]> wrote:
> go ahead and commit! :o)
>
> stefan
>
> Michaël Michaud schrieb:
> > Hi,
> >
> > Sorry to come back with these database access suggestions.
> > I'd like to commit the changes proposed here after as I need it to
> > access my postgis database and I'd rather keep my local version of
> > OpenJUMP synchronized with the CVS, but this code is quite important for
> > database access, and I'd rather get at least one feed back before
> > committing.
> >
> > Thanks a lot
> >
> > Michaël Michaud
> >
> > Michaël Michaud a écrit :
> >
> >> Hi,
> >>
> >> This one is for datastore api authors (Martin, Jon ?)
> >> I have a few suggestions/questions about this api implementation, but
> >> I'd rather have author's advice before any change :
> >>
> >> 1/ PostgisValueConverterFactory
> >> I think that for geometry column, getConverter should return
> >> WKB_GEOMETRY_MAPPER instead of WKT_GEOMETRY_MAPPER (geometries seem to
> >> have been stored in wkb instead of wkt since postgis 1.0)
> >
> > if (dbTypeName.equalsIgnoreCase("geometry"))
> > // WKB is now the normal way to store geometry in PostGIS
> > [mmichaud 2007-05-13]
> > return WKB_GEOMETRY_MAPPER;
> >
> >> 2/ PostgisResultSetConverter
> >> In init(), if the resultsetmetadata contains more than one geometry,
> >> we could keep the first one as AttributeType.GEOMETRY and read others
> >> as AttributeType.STRING instead of throwing an exception.
> >
> > // Convert the first geometry into AttributeType.GEOMETRY and the
> > following ones
> > // into AttributeType.STRINGs [mmichaud 2007-05-13]
> > if (mapper[i].getType() == AttributeType.GEOMETRY) {
> > if (featureSchema.getGeometryIndex() == -1) {
> > colName = "GEOMETRY";
> > featureSchema.addAttribute(colName, mapper[i].getType());
> > }
> > else {
> > mapper[i] = ValueConverterFactory.STRING_MAPPER;
> > featureSchema.addAttribute(colName, AttributeType.STRING);
> > }
> > }
> > else {
> > featureSchema.addAttribute(colName, mapper[i].getType());
> > }
> >
> >
> >> 3/ PostgisSQLBuilder
> >> It seems that adding double quotes around field names make it possible
> >> to query field name either in lower case or in upper case. I don't
> >> know if there are drawbacks. I saw somewhere in the code
> >> (PostgisDSMetadata) that you explicitly lower field names.
> >
> > private String getColumnListSpecifier(
> > String[] colName, String geomColName)
> > {
> > // Added double quotes around each table name in order to read mixed
> > case table names
> > // correctly [mmichaud 2007-05-13]
> > StringBuffer buf = new StringBuffer();
> > buf.append("AsBinary(\"" + geomColName + "\") as " + geomColName +
> > "_wkb");
> > for (int i = 0; i < colName.length; i++) {
> > if (! geomColName.equalsIgnoreCase(colName[i])) {
> > buf.append(",\"");
> > buf.append(colName[i]).append("\"");
> > }
> > }
> > return buf.toString();
> > }
> >
> >> The last one is a question :
> >> In the code, the geometry field is changed to binary with
> >> AsBinary(geometry) before it is read by WKBReader, even if the
> >> geometry is stored as wkb.
> >> I tried to read the field as is to avoid the asBinary() overhead but I
> >> did not succeed.
> >> I think this is a format pb (wkb vs ewkb ?), but the WKBReader from
> >> JTS claims to read ewkb.
> >> May be it is important to keep asBinary function to be able to read
> >> geometry without regarding its format, but on the other hand, it
> >> should be nice to be able to write query as
> >> select geometry, name from country
> >> instead of
> >> select asBinary(geometry), name from country, which is a lot less
> >> intuitive
> >>
> >> Cheers, and thanks again for the great lib
> >>
> >> Michael
> >>
> >>
> >>
> >> Michaël Michaud a écrit :
> >>
> >>> Hi everybody,
> >>>
> >>> I tried to understand differences between the 4 versions of
> >>> postgresql/postgis drivers I found at different places.
> >>> Here are the results of my investigations
> >>> Comments are welcome.
> >>>
> >>> *Different versions I found
> >>> *1 - a plugin (postgis_1_0_0.jar) from 2005 written by Markus Schaber
> >>> and bundled with OpenJUMP distribution. As far as I could see, the
> >>> plugin is bundled but unused in the distribution (nothing happened,
> >>> even after I have had the jar file to the classpath)
> >>> 2 - a plugin from uwe dalluege distributed as the "PostGIS PlugIn" on
> >>> OpenJUMP sourceforge site (2006-11-19). May be based on the previous
> >>> one.
> >>> 3 - datastore api from vividsolutions added to the code on december
> >>> of 2005, but not activated in the original jump version
> >>> 4 - paolo rizzi's SIS plugin for postgresql/postgis and oracle
> >>> database access, based on the framework developped in 3
> >>>
> >>> *Disimilarities between versions*
> >>> *1 - postgis plugin* 1.0.0
> >>> - Don't know how to make this postgis_1_0_0.jar work. If it has no
> >>> use, it should be removed from the distribution
> >>> *2 - Uwe's postgis plugin*
> >>> - the plugin is the only one able to create/update the database.
> >>> Other ones are read only
> >>> - it works well with postgresql 8.2 and postgis 1.1+
> >>> - the plugin load data from the load dataset menu and does not use
> >>> the nice interface from vividsolution in the layer menu (see 3)
> >>> - the plugin load data (in-memory) and does not offer a select option
> >>> or a feature-on-demand option
> >>> *3 - Vividsolutions's framework*
> >>> - Vividsolutions's datastore api has a nice design and a nice user
> >>> interface, but at the moment, it is read-only.
> >>> - the interface make it possible to cache features (in-memory ?) or
> >>> not (feature on demand ?)
> >>> - I could not read a posgis table with Vividsolution's api and
> >>> OpenJUMP until I made two changes in the code :
> >>> a) in PostgisValueConverterFactory, if dbTypeName is geometry, I
> >>> return WKB mapper instead of WKT (since postgis 1.0, default storage
> >>> format in postgis is binary)
> >>> b) If there are more than one geometry type in the resultset, the
> >>> second is read as AttributeType.STRING instead of throwing an
> >>> exception (in a select * statement, I can get more than one geometry
> >>> from my database).
> >>> *4 - SIS PlugIn from Paolo Rizzi
> >>> *- The plugin is based on Vividsolutions's api
> >>> - It is a read-only driver for postgis and oracle tables
> >>> - The plugin includes many dependencies (3 Mo). I don't know why it
> >>> needs all this stuff because there is not much more features in this
> >>> plugin than in vivid's api (maybe hidden classes for futur work).
> >>> - I found postgis_1_1_0 in dependencies but I don't know if it is
> >>> related to 1- and if it is used
> >>> - I get geometry, int, double and date values, but I cannot get
> >>> string values when loading a table or a selection !
> >>>
> >>> PS : I know there is also a hard work done by projet-SIGLE team to
> >>> write a generic data/database driver called GDBMS...
> >>>
> >>> Hope that helps,
> >>>
> >>> Michaël
> >>>
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> >>
> >
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