Geografic-Information-System/scripts/v.db.join/v.db.join.html

<h2>DESCRIPTION</h2>

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

<h2>NOTES</h2>

<em>v.db.join</em> is a front-end to <em>db.execute</em> 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 <em>db.in.ogr</em>.
<p>
The vector map-database connection(s) can be verified with <em>v.db.connect</em>.

<h2>EXAMPLE</h2>

Joining the soil type explanations from table <em>soils_legend</em>
into the Spearfish soils map (<a href="http://www.grassbook.org/examples_menu.php">download legend)</a>:

<div class="code"><pre>
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
...
</pre></div>

<h2>SEE ALSO</h2>

<em><a HREF="db.execute.html">db.execute</a></em>,
<em><a HREF="db.in.ogr.html">db.in.ogr</a></em>,
<em><a HREF="v.db.update.html">v.db.update</a></em><br>
<em><a href="sql.html">GRASS SQL interface</a></em>

<h2>AUTHOR</h2>

Markus Neteler

<p><i>Last changed: $Date$</i>