.TH grass-pg 1grass "" "GRASS 8.2.1" "GRASS GIS User's Manual"
.SH PostgreSQL DATABASE DRIVER
PostgreSQL database driver enables GRASS to store vector attributes in
PostgreSQL server.
.SH Creating a PostgreSQL database
A new database is created with createdb, see
the PostgreSQL
manual for details.
.SH Connecting GRASS to PostgreSQL
.br
.nf
\fC
# example for connecting to a PostgreSQL server:
db.connect driver=pg database=mydb
db.login user=myname password=secret host=myserver.osgeo.org  # port=5432
db.connect \-p
db.tables \-p
\fR
.fi
.SS Username and password
From the PostgresQL manual:
.PP
The file \fI.pgpass\fR in a user\(cqs home directory can contain
passwords to be used if the connection requires a password (and no
password has been specified otherwise). On Microsoft Windows the file
is named \fI%APPDATA%\(rspostgresql\(rspgpass.conf\fR (where
\fI%APPDATA%\fR refers to the Application Data subdirectory in the
user\(cqs profile). Alternatively, a password file can be specified using
the connection parameter passfile or the environment variable
PGPASSFILE.
This file should contain lines of the following format:
.br
.nf
\fC
hostname:port:database:username:password
\fR
.fi
.SH Supported SQL commands
All SQL commands supported by PostgreSQL.
It\(cqs not possible to use C\-like escapes (with backslash like \(rsn etc)
within the SQL syntax.
.SH Operators available in conditions
All SQL operators supported by PostgreSQL.
.SH Adding an unique ID column
Import vector module require an unique ID column which can
be generated as follows in a PostgreSQL table:
.br
.nf
\fC
db.execute sql=\(dqALTER TABLE mytable ADD ID integer\(dq
db.execute sql=\(dqCREATE SEQUENCE mytable_seq\(dq
db.execute sql=\(dqUPDATE mytable SET ID = nextval(\(cqmytable_seq\(cq)\(dq
db.execute sql=\(dqDROP SEQUENCE mytable_seq\(dq
\fR
.fi
.SH Attribute import into PostgreSQL
CSV import into PostgreSQL:
.br
.nf
\fC
\(rsh copy
COPY t1 FROM \(cqfilename\(cq USING DELIMITERS \(cq,\(cq;
\fR
.fi
.SH Geometry import from PostgreSQL table into GRASS
\fIv.in.db\fR creates a new vector
(points) map from a database table containing
coordinates. See here for examples.
.SH PostGIS: PostgreSQL with vector geometry
PostGIS:
adds geographic object support to PostgreSQL.
.SS Example: Import from PostGIS
In an existing PostGIS database, create the following table:
.br
.nf
\fC
CREATE TABLE test
(
 id serial NOT NULL,
 mytime timestamp DEFAULT now(),
 text varchar,
 wkb_geometry geometry,
 CONSTRAINT test_pkey PRIMARY KEY (id)
) WITHOUT OIDS;
# insert value
INSERT INTO test (text, wkb_geometry)
 VALUES (\(cqName\(cq,geometryFromText(\(cqPOLYGON((600000 200000,650000
 200000,650000 250000,600000 250000,600000 200000))\(cq,\-1));
# register geometry column
select AddGeometryColumn (\(cqpostgis\(cq, \(cqtest\(cq, \(cqgeometry\(cq, \-1, \(cqGEOMETRY\(cq, 2);
\fR
.fi
GRASS can import this PostGIS polygon map as follows:
.br
.nf
\fC
v.in.ogr input=\(dqPG:host=localhost dbname=postgis user=neteler\(dq layer=test \(rs
         output=test type=boundary,centroid
v.db.select test
v.info \-t test
\fR
.fi
.SS Geometry Converters
.RS 4n
.IP \(bu 4n
PostGIS with shp2pgsql:
.br
shp2pgsql \-D lakespy2 lakespy2 test > lakespy2.sql
.IP \(bu 4n
e00pg: E00 to PostGIS filter,
see also \fIv.in.e00\fR.
.IP \(bu 4n
GDAL/OGR ogrinfo and ogr2ogr:
GIS vector format converter and library, e.g. ArcInfo or SHAPE to PostGIS.
.br
ogr2ogr \-f \(dqPostgreSQL\(dq shapefile ??
.RE
.SH SEE ALSO
\fI
db.connect,
db.execute
\fR
.PP
Database management in GRASS GIS
.br
Help pages for database modules
.br
SQL support in GRASS GIS
.br
.SH REFERENCES
.RS 4n
.IP \(bu 4n
PostgreSQL web site
.IP \(bu 4n
pgAdmin graphical user interface
.IP \(bu 4n
GDAL/OGR PostgreSQL
driver documentation
.RE
.PP
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.PP
© 2003\-2023
GRASS Development Team,
GRASS GIS 8.2.1 Reference Manual