## DESCRIPTION

db.execute allows the user to execute SQL statements.

## NOTES

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

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

## SEE ALSO

db.columns, db.describe, db.drivers, db.droptable, db.login, db.select, db.tables, GRASS SQL interface

## AUTHOR

CERL

Last changed: $Date: 2007/05/17 08:55:11 $