Supported SQL commandsAll SQL commands supported by ODBC.
Operators available in conditionsAll SQL operators supported by ODBC.
EXAMPLEIn 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
MS-WindowsOn 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.
LinuxConfigure ODBC driver for selected database (manually or with 'ODBCConfig'). ODBC drivers are defined in /etc/odbcinst.ini. Here an example:
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:
Description = PostgreSQL
Driver = PostgreSQL
Trace = No
Database = grass6test
Servername = localhost
UserName = neteler
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 driverNow 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 \
Finally a test: Here we should see the table columns (if the ODBC connection works):
Now the table name 'mytable' should appear.
Doesn't work? Check with 'isql ' 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.