grass-mysql(1grass)						Grass User's Manual					       grass-mysql(1grass)

NAME

       grass-mysql - MySQL driver

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

       Because	vector attribute tables are created automaticaly when a new vector is written and the name of the table is the same as the name of
       the vector it is good practice to create a new database for each GRASS mapset.

Creating a MySQL database
       A new database is created within MySQL:
       mysql> CREATE DATABASE mydb;
	See the MySQL manual for details.

Driver and database name
       GRASS modules require 2 parameters to connect to a database.  Those parameters are 'driver' and 'database'. For MySQL driver the  parameter
       'driver' should be set to value 'mysql'.  The parameter 'database' can be given in two formats:

		      Database name - in case of connection from localhost

		      String of comma separated list of kye=value options.  Supported options are:

			     dbname - database name

			     host - host name or IP address

			     port - server port number
       Examples of connection parameters:
	 db.connect driver=mysql database=mytest
	 db.connect driver=mysql database='dbname=mytest,host=test.grass.org'

Data types
       GRASS supports almost all MySQL data types with following limitations:

		      Binary columns (BINARY, VARBINARY, TINYBLOB, MEDIUMBLOB, BLOB, LONGBLOB) are not not supported.  If a table with binary col-
		     umn(s) is used in GRASS a warning is printed and only the supported columns are returned in query results.

		      Columns of type SET and ENUM are represented as string (VARCHAR).

		      Very large integers in columns of type BIGINT can be lost or corrupted because GRASS does not support 64	bin  integeres	on
		     most platforms.

		      GRASS does not currently distinguish types TIMESTAMP and DATETIME. Both types are in GRASS interpreted as TIMESTAMP.

Indexes
       GRASS  modules  automaticaly create index on key column of vector attributes table. The index on key column is important for performance of
       modules which update the attribute table, for example v.to.db, v.distance and v.what.rast.

Privileges
       Because MySQL does not support groups of users and because only MySQL 'root' can grant privileges to other users GRASS cannot  automaticaly
       grant select privileges on created tables to group of users.

       If  you want to give privilege to read data from your mapset to other users you have to ask your MySQL server administrator to grant select
       privilege to them on the MySQL database used for that mapset. For example, to allow  everybody to read data in from your database 'mydb':

       shell> mysql --user=root mysql
       mysql> GRANT SELECT ON mydb.* TO ''@'%';

Schemas
       Because MySQL does not support database schemas the parameter 'schema' of module db.connect should never be set to any value.  If  you  set
       that parameter for MySQL driver GRASS will try to write tables to the specified schema which will result in errors.

Groups
       MySQL does not support user groups. Any settings specified by 'group' parameter of module db.connect are ignored by GRASS for MySQL driver.

SEE ALSO

	db.connect, SQL support in GRASS GIS

Credits
       Development of the driver was sponsored by Faunalia (Italy) as part of a project for ATAC.

AUTHOR

       Radim Blazek

       Last changed: $Date: 2011-02-07 18:59:50 +0100 (Mon, 07 Feb 2011) $
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GRASS 6.4.2														       grass-mysql(1grass)