NAME¶
db.execute - Executes any SQL statement.
KEYWORDS¶
database, attribute table, SQL
SYNOPSIS¶
db.execute
db.execute help
db.execute [-
i] [
input=
name]
[
driver=
name] [
database=
name] [--
verbose]
[--
quiet]
Flags:¶
- -i
-
Ignore SQL errors and continue
- --verbose
-
Verbose module output
- --quiet
-
Quiet module output
Parameters:¶
- input=name
-
Name of file containing SQL statements
If not given or '-' read from standard input
- driver=name
-
Driver name
Options: pg,dbf,ogr,odbc,mysql,sqlite
Default: dbf
- database=name
-
Database name
Default: $GISDBASE/$LOCATION_NAME/$MAPSET/dbf/
DESCRIPTION¶
db.execute allows the user to execute SQL statements.
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 much faster to
place all the SQL statements into a text file and use
db.execute's
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 sql driver pages for how to create a new database.
EXAMPLES¶
Create a new table with columns 'cat' and 'soiltype':
echo 'create table soils (cat integer, soiltype varchar(10) )' | db.execute
Create a new table using a file with SQL statements:
db.execute driver=odbc database=g60test input=file.sql
Insert new row into attribute table:
echo "INSERT INTO nobugs (id,name,east_gb,north_gb) values
(30,'Ala',1657340,5072301)" | db.execute
Update attribute entries to new value based on SQL rule:
echo "UPDATE roads SET travelcost=5 WHERE cat=1" | db.execute
Update attribute entries to new value based on SQL rule:
echo "UPDATE dourokukan SET testc=50 WHERE testc is NULL" | db.execute
Delete selected rows from attribute table:
echo "DELETE FROM gsod_stationlist WHERE latitude < -91" |
db.execute
Add new column to attribute table:
echo "ALTER TABLE roads ADD COLUMN length double" | db.execute
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
Drop column from attribute table:
echo "ALTER TABLE roads DROP COLUMN length" | db.execute
Drop table (not supported by all drivers)
echo "DROP TABLE fmacopy" | db.execute
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;
cat file.sql | db.execute
Join table 'myroads' into table 'extratab' based on common 'cat' column
values (not supported by DBF driver):
echo "UPDATE extratab SET names=(SELECT label FROM myroads WHERE
extratab.cat=myroads.cat);" | db.execute
SEE ALSO¶
db.columns, db.describe, db.drivers, db.droptable,
db.login, db.select, db.tables, GRASS SQL
interface
AUTHOR¶
CERL
Last changed: $Date: 2011-11-08 12:29:50 +0100 (Tue, 08 Nov 2011) $
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