ÐÐÐСÐÐÐÐ

   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.

ÐÐ ÐÐÐЧÐÐÐЯ

   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.

ÐÐ ÐÐÐРЫ

   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'"

СÐ. ТÐÐÐÐ

   [1]db.execute, [2]v.db.addcol, [3]v.db.addtable, [4]v.db.connect,
   [5]v.db.droptable, [6]v.db.join, [7]v.db.select
   [8]GRASS SQL interface

ÐÐТÐÐ

   Moritz Lennert (mlennert@club.worldonline.be)

   Last changed: $Date: 2007-06-29 02:51:12 -0500 (ÐÑ, 29 иÑн 2007) $

ÐвÑÐ¾Ñ Ð¿ÐµÑевода

References

   1. file://localhost/root/tmp/2/fin/db.execute.html
   2. file://localhost/root/tmp/2/fin/v.db.addcol.html
   3. file://localhost/root/tmp/2/fin/v.db.addtable.html
   4. file://localhost/root/tmp/2/fin/v.db.connect.html
   5. file://localhost/root/tmp/2/fin/v.db.droptable.html
   6. file://localhost/root/tmp/2/fin/v.db.join.html
   7. file://localhost/root/tmp/2/fin/v.db.select.html
   8. file://localhost/root/tmp/2/fin/sql.html