|grass-odbc(1grass)||GRASS GIS User's Manual||grass-odbc(1grass)|
ODBC DATABASE DRIVER¶
Communication between GRASS and ODBC database for attribute management:
|GRASS module <->||<-->||ODBC Interface||<-->||RDBMS|
|GRASS||DBMI driver||unixODBC||ODBC driver||PostgreSQL|
Supported SQL commands¶
All SQL commands supported by ODBC.
Operators available in conditions¶
All SQL operators supported by ODBC.
In this example we copy the dbf file of a SHAPE map into ODBC, then connect GRASS to the ODBC DBMS. Usually the table will be already present in the DBMS.
Defining the ODBC connection¶
On MS-Windows, in order to be able to connect, the ODBC connection needs to be configured using dedicated tools (tool called "ODBC Data Source Administrator") and give a name to that connection. This name is then used as database name when accessing from a client via ODBC.
Configure ODBC driver for selected database (manually or with ’ODBCConfig’). ODBC drivers are defined in /etc/odbcinst.ini. Here an example:
[PostgreSQL] Description = ODBC for PostgreSQL Driver = /usr/lib/libodbcpsql.so Setup = /usr/lib/libodbcpsqlS.so FileUsage = 1
Create DSN (data source name). The DSN is used as database name in db.* modules. Then DSN must be defined in $HOME/.odbc.ini (for this user only) or in /etc/odbc.ini for (for all users) [watch out for the database name which appears twice and also for the PostgreSQL protocol version]. Omit blanks at the beginning of lines:
[grass6test] Description = PostgreSQL Driver = PostgreSQL Trace = No TraceFile = Database = grass6test Servername = localhost UserName = neteler Password = Port = 5432 Protocol = 8.0 ReadOnly = No RowVersioning = No ShowSystemTables = No ShowOidColumn = No FakeOidIndex = No ConnSettings =Configuration of an DSN without GUI is described on http://www.unixodbc.org/odbcinst.html, but odbc.ini and .odbc.ini may be created by the ’ODBCConfig’ tool. You can easily view your DSN structure by ’DataManager’. Configuration with GUI is described on http://www.unixodbc.org/doc/UserManual/
To find out about your PostgreSQL protocol, run:
Using the ODBC driver¶
Now create a new database if not yet existing:
db.createdb driver=odbc database=grass6test
To store a table ’mytable.dbf’ (here: in current directory) into PostgreSQL through ODBC, run:
db.connect driver=odbc database=grass6test db.copy from_driver=dbf from_database=./ from_table=mytable \
to_driver=odbc to_database=grass6test to_table=mytable
Next link the map to the attribute table (now the ODBC table is used, not the dbf file):
v.db.connect map=mytable.shp table=mytable key=ID \
database=grass6test driver=odbc v.db.connect -p
Finally a test: Here we should see the table columns (if the ODBC
db.tables -p db.columns table=mytable
Now the table name ’mytable’ should appear.
Doesn’t work? Check with ’isql <databasename>’ if the ODBC-PostgreSQL connection is really established.
Note that you can also connect mySQL, Oracle etc. through ODBC to GRASS.
You can also check the vector map itself concerning a current link to a table:
v.db.connect -p mytable.shp
which should print the database connection through ODBC to the defined RDBMS.
db.connect, v.db.connect, unixODBC web site, SQL support in GRASS GIS
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© 2003-2020 GRASS Development Team, GRASS GIS 7.8.5 Reference Manual