[GRASS-user] How to copy vector columns between databases

[peter.loewe at gmx.de]

Hi,

I have a vector layer FOO which is linked to two tables in layers 1 and 2.
The categories for each vector element are different in layer 1 and (e.g. a certain area may have the cat value "51" in layer 1 and a cat value of "42" in layer 2).
Let's assume that layer one has a VARCHAR column containing the names of the region (e.g. database_layer_1: 51,"Wolfenstein" database_layer_2: 42 )

If a new VARCHAR column is added to layer 2 by v.db.adcol,
how can the the names from layer 1 be copied into it?

[Goal: database_layer_1: 51,"Wolfenstein" database_layer_2: 42,"Wolfenstein" ]

Unfortunately, v.db.update seems only to work within one layer.

An UPDATE/SELECT SQL-statement will not be possible unless a table can be produced which holds the categories for both database layers for each geometry element.

How can this be solved ?

Regards,
Peter

-- 
Dr. Peter Löwe
<peter.loewe at gmx.de>





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