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v.db.update(1grass) | Grass User's Manual | v.db.update(1grass) |
NAME¶
v.db.update - Updates a column in the attribute table connected to a vector map.KEYWORDS¶
vector, database, attribute tableSYNOPSIS¶
v.db.updateParameters:¶
- map=string
-
- layer=string
-
- column=string
-
- value=string
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- qcolumn=string
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- where=string
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DESCRIPTION¶
v.db.update assigns a new value to a column in the attribute table connected to a given map. The value parameter updates with a literal value. Alternatively, with the qcol parameter values can be copied from another column in the table or be the result of a combination or transformation of other columns.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¶
In this example, selectively display lakes without (blue) and with NULL (red) are shown to find out which type is undefined. In the original map there are lakes missing FTYPE attribute which are wetlands along streams. These NULL attributes are replaced with the landuse type WETLAND:where="FTYPE IS NULL"
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.selectAUTHOR¶
Moritz Lennert (mlennert@club.worldonline.be) Last changed: $Date: 2013-05-02 11:29:18 +0200 (Thu, 02 May 2013) $ Full index © 2003-2014 GRASS Development TeamGRASS 6.4.4 |