## NAME

v.db.join

## DESCRIPTION

v.db.join joins the content of another table into the connected attribute table of a vector map.

## NOTES

v.db.join is a front-end to db.execute to allow easier usage. The vector attribute table must be stored in a SQL database (SQLite, PostgreSQL, MySQL, ODBC, ...). The DBF backend is not supported. Tables can be imported with db.in.ogr.

The vector map-database connection(s) can be verified with v.db.connect.

## EXAMPLE

Joining the soil type explanations from table soils_legend into the Spearfish soils map (download legend):

    g.copy vect=soils,mysoils

    # import legend table
    db.in.ogr soils_legend.csv out=soils_legend

    # get join column names
    v.info -c mysoils
    db.describe -c soils_legend

    # look at original table
    v.db.select mysoils
    cat|label
    1|Aab
    2|Ba
    3|Bb
    4|BcB
    5|BcC
    ...

    # look at legend
    db.select soils_legend
    db.select soils_legend | head -7
    id|shortname|longname
    0|no data|no data
    0|AaB|Alice fine sandy loam, 0 to 6
    0|Ba|Barnum silt loam
    0|Bb|Barnum silt loam, channeled
    0|BcB|Boneek silt loam, 2 to 6
    0|BcC|Boneek silt loam, 6 to 9
    ...

    # join soils_legend into mysoils attribute table
    v.db.join mysoils col=label otable=soils_legend ocol=shortname

    # verification of join
    v.db.select mysoils
    cat|label|id|shortname|longname
    1|Aab|||
    2|Ba|2|Ba|Barnum silt loam
    3|Bb|3|Bb|Barnum silt loam, channeled
    4|BcB|4|BcB|Boneek silt loam, 2 to 6
    5|BcC|5|BcC|Boneek silt loam, 6 to 9
    ...

## SEE ALSO

db.execute, db.in.ogr, v.db.update
GRASS SQL interface

## AUTHOR

Markus Neteler

Last changed: $Date: 2011-11-08 10:42:51 +0100 (Tue, 08 Nov 2011) $

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