1grass-mysql(1)              GRASS GIS User's Manual             grass-mysql(1)
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MySQL DATABASE DRIVER

6       MySQL database driver enables GRASS to store vector attributes in MySQL
7       server.
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9       Because vector attribute tables are created automatically  when  a  new
10       vector  is written and the name of the table is the same as the name of
11       the vector it is good practice to create a new database for each  GRASS
12       mapset.
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Creating a MySQL database

15       A new database is created within MySQL:
16       mysql> CREATE DATABASE mydb;
17       See the MySQL manual for details.
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Driver and database name

20       GRASS modules require 2 parameters to connect to a database.  Those pa‐
21       rameters are ’driver’ and ’database’. For MySQL  driver  the  parameter
22       ’driver’  should be set to value ’mysql’.  The parameter ’database’ can
23       be given in two formats:
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25           •   Database name - in case of connection from localhost
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27           •   String of comma separated list of kye=value options.  Supported
28               options are:
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30               •   dbname - database name
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32               •   host - host name or IP address
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34               •   port - server port number
35       Examples of connection parameters:
36         db.connect driver=mysql database=mytest
37         db.connect driver=mysql database=’dbname=mytest,host=test.grass.org’
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Data types

40       GRASS supports almost all MySQL data types with following limitations:
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42           •   Binary  columns (BINARY, VARBINARY, TINYBLOB, MEDIUMBLOB, BLOB,
43               LONGBLOB) are not not supported.  If a table with  binary  col‐
44               umn(s)  is used in GRASS a warning is printed and only the sup‐
45               ported columns are returned in query results.
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47           •   Columns of type SET and ENUM are represented  as  string  (VAR‐
48               CHAR).
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50           •   Very  large  integers  in columns of type BIGINT can be lost or
51               corrupted because GRASS does not support 64  bin  integeres  on
52               most platforms.
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54           •   GRASS  does not currently distinguish types TIMESTAMP and DATE‐
55               TIME. Both types are in GRASS interpreted as TIMESTAMP.
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Indexes

58       GRASS modules automatically create index on key column  of  vector  at‐
59       tributes table. The index on key column is important for performance of
60       modules which update the attribute table, for example  v.to.db,  v.dis‐
61       tance and v.what.rast.
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Privileges

64       Because  MySQL  does not support groups of users and because only MySQL
65       ’root’ can grant privileges to other users GRASS  cannot  automatically
66       grant select privileges on created tables to group of users.
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68       If  you  want  to give privilege to read data from your mapset to other
69       users you have to ask your MySQL server administrator to  grant  select
70       privilege to them on the MySQL database used for that mapset. For exam‐
71       ple, to allow  everybody to read data in from your database ’mydb’:
72       shell> mysql --user=root mysql
73       mysql> GRANT SELECT ON mydb.* TO ’’@’%’;
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Schemas

76       Because MySQL does not support database schemas the parameter  ’schema’
77       of  module db.connect should never be set to any value. If you set that
78       parameter for MySQL driver GRASS will try to write tables to the speci‐
79       fied schema which will result in errors.
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Groups

82       MySQL  does  not support user groups. Any settings specified by ’group’
83       parameter of module db.connect are ignored by GRASS for MySQL driver.
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Troubleshooting: SQL syntax error

86       Attempting to use a reserved SQL word as column or table name will  re‐
87       sult  in a "SQL syntax" error. The list of reserved words for MySQL can
88       be found in the MySQL manual.
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SEE ALSO

91        db.connect, SQL support in GRASS GIS
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Credits

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

98       Radim Blazek
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100       Main index | Topics index | Keywords index | Graphical index | Full in‐
101       dex
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103       © 2003-2023 GRASS Development Team, GRASS GIS 8.2.1 Reference Manual
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107GRASS 8.2.1                                                     grass-mysql(1)
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