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v.db.update

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v.db.update: Allows to update a column in the attribute table connected to a vector map.

NAME

v.db.update - Allows to update a column in the attribute table connected to a vector map.

KEYWORDS

vector, database, attribute table

SYNOPSIS

v.db.update v.db.update help v.db.update map=string [layer=integer] column=string [value=string] [qcolumn=string] [where=string] [--verbose] [--quiet] Parameters: map=string Vector map to edit the attribute table for layer=integer Layer to which the table to be changed is connected Default: 1 column=string Column to update value=string Value to update the column with (varchar values have to be in single quotes, e.g. 'grass') qcolumn=string Column to query where=string WHERE conditions for update, without 'where' keyword (e.g. cat=1 or col1/col2>1)

DESCRIPTION

v.db.update allows to assign a new value to a column in the attribute table connected to a given map. Alternatively, values can be copied from another column in the table.
NOTES
v.db.update is just a front-end to db.execute to allow easier usage. For complex SQL UPDATE statements, db.execute should be used.
EXAMPLES
Spearfish: adding new column, inserting selectively a specified value: g.copy vect=fields,myfields v.db.addcol myfields col="polynum integer" v.db.update myfields col=polynum val=42 where="label='V. White#1'" v.db.select myfields Spearfish: adding new column, copying values from other table column with on the fly calculation: g.copy vect=fields,myfields v.db.addcol myfields col="polynum integer" v.db.update myfields col=polynum qcol="cat*2" v.db.select myfields Type cast (type conversion) of strings to double precision (unsupported by DBF driver): v.db.update mygeodetic_pts col=zval qcol="CAST(z_value AS double precision)" \ where="z_value <> 'N/A'"

SEE ALSO

db.execute, v.db.addcol, v.db.addtable, v.db.connect, v.db.droptable, v.db.join, v.db.select GRASS SQL interface

AUTHOR

Moritz Lennert (mlennert@club.worldonline.be) Last changed: $Date: 2007-06-29 09:51:12 +0200 (Fri, 29 Jun 2007) $ Full index (C) 2003-2010 GRASS Development Team V.DB.UPDATE(1)
 
 
 

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