PostgreSQL DATABASE DRIVER

       PostgreSQL database driver enables GRASS to store vector attributes in PostgreSQL server.

Creating a PostgreSQL database

       A new database is created with createdb, see the PostgreSQL manual for details.

Connecting GRASS to PostgreSQL

       # 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

   Username and password
       From the PostgresQL manual:

       The file .pgpass in a user’s 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
       %APPDATA%\postgresql\pgpass.conf  (where  %APPDATA%  refers  to  the Application Data subdirectory in the
       user’s 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:
       hostname:port:database:username:password

Supported SQL commands

       All  SQL  commands supported by PostgreSQL.  It’s not possible to use C-like escapes (with backslash like
       \n etc) within the SQL syntax.

Operators available in conditions

       All SQL operators supported by PostgreSQL.

Adding an unique ID column

       Import vector module require an unique ID column which can be generated as follows in a PostgreSQL table:
       db.execute sql="ALTER TABLE mytable ADD ID integer"
       db.execute sql="CREATE SEQUENCE mytable_seq"
       db.execute sql="UPDATE mytable SET ID = nextval(’mytable_seq’)"
       db.execute sql="DROP SEQUENCE mytable_seq"

Attribute import into PostgreSQL

       CSV import into PostgreSQL:
       \h copy
       COPY t1 FROM ’filename’ USING DELIMITERS ’,’;

Geometry import from PostgreSQL table into GRASS

       v.in.db creates a new vector (points) map from a database table  containing  coordinates.  See  here  for
       examples.

PostGIS: PostgreSQL with vector geometry

       PostGIS: adds geographic object support to PostgreSQL.

   Example: Import from PostGIS
       In an existing PostGIS database, create the following table:
       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 (’Name’,geometryFromText(’POLYGON((600000 200000,650000
        200000,650000 250000,600000 250000,600000 200000))’,-1));
       # register geometry column
       select AddGeometryColumn (’postgis’, ’test’, ’geometry’, -1, ’GEOMETRY’, 2);
       GRASS can import this PostGIS polygon map as follows:
       v.in.ogr input="PG:host=localhost dbname=postgis user=neteler" layer=test \
                output=test type=boundary,centroid
       v.db.select test
       v.info -t test

   Geometry Converters
           •   PostGIS with shp2pgsql:
               shp2pgsql -D lakespy2 lakespy2 test > lakespy2.sql

           •   e00pg: E00 to PostGIS filter, see also v.in.e00.

           •   GDAL/OGR  ogrinfo  and ogr2ogr: GIS vector format converter and library, e.g. ArcInfo or SHAPE to
               PostGIS.
               ogr2ogr -f "PostgreSQL" shapefile ??

SEE ALSO

        db.connect, db.execute

       Database management in GRASS GIS
       Help pages for database modules
       SQL support in GRASS GIS

REFERENCES

           •   PostgreSQL web site

           •   pgAdmin graphical user interface

           •   GDAL/OGR PostgreSQL driver documentation

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       © 2003-2019 GRASS Development Team, GRASS GIS 7.8.2 Reference Manual