db.execute - Executes any SQL statement.
Contents
Description
db.execute allows the user to execute SQL statements.
Examples
Create a new table with columns ’cat’ and ’soiltype’:
db.execute sql="CREATE TABLE soils (cat integer, soiltype varchar(10))"
Create a new table using a file with SQL statements
db.execute driver=odbc database=grassdb input=file.sql
Insert new row into attribute table:
db.execute sql="INSERT INTO mysites (id,name,east,north) values (30,’Ala’,1657340,5072301)"
Update attribute entries to new value based on SQL rule:
db.execute sql="UPDATE roads SET travelcost=5 WHERE cat=1"
Update attribute entries to new value based on SQL rule:
db.execute sql="UPDATE dourokukan SET testc=50 WHERE testc is NULL"
Delete selected rows from attribute table:
db.execute sql="DELETE FROM gsod_stationlist WHERE latitude < -91"
Add new column to attribute table:
db.execute sql="ALTER TABLE roads ADD COLUMN length double"
Column type conversion - update new column from existing column (all drivers except for DBF):
# ’z_value’ is varchar and ’z’ is double precision:
echo "UPDATE geodetic_pts SET z = CAST(z_value AS numeric)" | db.execute input=-
Drop column from attribute table:
db.execute sql="ALTER TABLE roads DROP COLUMN length"
Drop table (not supported by all drivers):
db.execute sql="DROP TABLE fmacopy"
Update attribute with multiple SQL instructions in file (e.g., file.sql, instruction line must end with a
semicolon):
UPDATE roads SET travelcost=5 WHERE cat=1;
UPDATE roads SET travelcost=2 WHERE cat=2;
db.execute input=file.sql
Join table ’myroads’ to table ’extratab’ based on common ’cat’ column values (not supported by DBF
driver):
db.execute sql="UPDATE extratab SET names=(SELECT label FROM myroads WHERE extratab.cat=myroads.cat)"
Keywords
database, attribute table, SQL
Name
db.execute - Executes any SQL statement.
For SELECT statements use ’db.select’.
Notes
db.execute only executes SQL statements and does not return any data. If you need data returned from the
database, use db.select.
If parameters for database connection are already set with db.connect, they are taken as default values
and do not need to be specified each time.
If you have a large number of SQL commands to process, it is much faster to place all the SQL statements
into a text file and use input file parameter than it is to process each statement individually in a
loop. If multiple instruction lines are given, each SQL line must end with a semicolon.
Please see the individual GRASSSQLinterface for how to create a new database.
See Also
db.columns,db.describe,db.drivers,db.droptable,db.login,db.select,db.tables,GRASSSQLinterface
Source Code
Available at: db.execute source code (history)
Accessed: Friday Apr 04 01:18:43 2025
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© 2003-2025 GRASS Development Team, GRASS GIS 8.4.1 Reference Manual
GRASS 8.4.1 db.execute(1grass)
Synopsis
db.executedb.execute--helpdb.execute [-i] [sql=sql_query] [input=name] [driver=name] [database=name] [schema=name]
[--help] [--verbose] [--quiet] [--ui]
Flags:-i
Ignore SQL errors and continue
--help
Print usage summary
--verbose
Verbose module output
--quiet
Quiet module output
--ui
Force launching GUI dialog
Parameters:sql=sql_query
SQL statement
Example: update rybniky set kapri = ’hodne’ where kapri = ’malo’
input=name
Name of file containing SQL statement(s)
’-’ for standard input
driver=name
Name of database driver
Options: dbf,mysql,odbc,ogr,pg,sqlite
Default: sqlitedatabase=name
Name of database
Default: $GISDBASE/$LOCATION_NAME/$MAPSET/sqlite/sqlite.dbschema=name
Database schema
Do not use this option if schemas are not supported by driver/database server
