Dear all,
I have attached a very small patch to v.out.org against the
version in 6.4.SVN. It adds a "-u" flag that allows users
to update data in existing OGR sources. It's the same as
ogr2ogr's "-update" option and _very_ important for being able
to write layers as tables into existing spatial databases.
It should not be able to break any existing functionality.
If a data source does not support updates (like Shapefiles),
then Ogr_Dr_open() behaves the same as Ogr_Dr_CreateDataSource().
Despite the update, I have not been able to successfully
write OGR features to an existing (or new) SQLite DB.
OGR_L_CreateFeature() results in this error from the SQLite driver
after the first feature has been written:
ERROR 1: sqlite3_step() failed:
SQL logic error or missing database
Strangely, the first feature is written into the table just fine,
but the error appears for all consecutive writes.
I will have to do more tests to see if this is an SQLite
and GRASS specific problem (ogr2ogr works fine).
Cheers,
Ben
--
Benjamin Ducke
Senior Geospatial Consultant
Oxford Archaeology
Janus House
Osney Mead
OX2 0ES
Oxford, U.K.
Tel: +44 (0)1865 263 800 (switchboard)
Tel: +44 (0)1865 980 758 (direct)
Fax :+44 (0)1865 793 496
[email protected]
------
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--- old/main.c 2009-05-11 10:16:32.000000000 +0100
+++ new/main.c 2009-05-11 10:16:25.000000000 +0100
@@ -44,7 +44,7 @@
struct GModule *module;
struct Option *in_opt, *dsn_opt, *layer_opt, *type_opt, *frmt_opt,
*field_opt, *dsco, *lco;
- struct Flag *cat_flag, *esristyle, *poly_flag;
+ struct Flag *cat_flag, *esristyle, *poly_flag, *update_flag;
char buf[2000];
char key1[200], key2[200];
struct Key_Value *projinfo, *projunits;
@@ -161,6 +161,12 @@
poly_flag->key = 'p';
poly_flag->description = _("Export lines as polygons");
+
+ update_flag = G_define_flag();
+ update_flag->key = 'u';
+ update_flag->description = _("Update an existing data source");
+
+
if (G_parser(argc, argv))
exit(EXIT_FAILURE);
@@ -249,22 +255,39 @@
G_fatal_error(_("OGR driver <%s> not found"), frmt_opt->answer);
Ogr_driver = OGRGetDriver(drn);
- /* parse dataset creation options */
- i = 0;
- while (dsco->answers[i]) {
- tokens = G_tokenize(dsco->answers[i], "=");
- if (G_number_of_tokens(tokens))
- papszDSCO = CSLSetNameValue(papszDSCO, tokens[0], tokens[1]);
- G_free_tokens(tokens);
- i++;
+ if ( update_flag->answer && dsco->answers ) {
+ G_warning (_("Running in update mode. Ignoring 'dsco' parameter"));
+ } else {
+ /* parse dataset creation options */
+ i = 0;
+ while (dsco->answers[i]) {
+ tokens = G_tokenize(dsco->answers[i], "=");
+ if (G_number_of_tokens(tokens))
+ papszDSCO = CSLSetNameValue(papszDSCO, tokens[0], tokens[1]);
+ G_free_tokens(tokens);
+ i++;
+ }
}
papszDSCO = dsco->answers;
- Ogr_ds = OGR_Dr_CreateDataSource(Ogr_driver, dsn_opt->answer, papszDSCO);
+
+ if ( update_flag->answer ) {
+ Ogr_ds =
+ OGR_Dr_Open(Ogr_driver, dsn_opt->answer, TRUE);
+ } else {
+ Ogr_ds = OGR_Dr_CreateDataSource(Ogr_driver, dsn_opt->answer, papszDSCO);
+ }
CSLDestroy(papszDSCO);
- if (Ogr_ds == NULL)
- G_fatal_error(_("Unable to open OGR data source '%s'"),
- dsn_opt->answer);
+ if (Ogr_ds == NULL) {
+ if ( !update_flag->answer ) {
+ G_fatal_error(_("Unable to create OGR data source '%s'. "
+ "Use the -u flag to update an existing data source"),
+ dsn_opt->answer);
+ } else {
+ G_fatal_error(_("Unable to open OGR data source '%s'"),
+ dsn_opt->answer);
+ }
+ }
/* parse layer creation options */
i = 0;
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