v.db.addtable.html

<h2>DESCRIPTION</h2>

<em>v.db.addtable</em> creates and adds a new attribute table to a given vector
map. It links the table to the specified layer of the vector map. If the vector
map is not yet linked to any table, new a database link is established based on
the MAPSET database settings (see <em>db.connect</em>).

<h2>NOTES</h2>

<em>v.db.addtable</em> is a front-end to <em>db.execute</em> to allow easier
usage.
<p>
<em>v.db.addtable</em> will only insert category values into the table for those features 
which actually have a category value in the relevant layer. The user can add 
category values automatically by using <em>v.category</em> or manually with 
<em><a href="wxGUI.vdigit.html">wxGUI vector digitizer</a></em>
before running v.db.addtable. Or one can run v.db.addtable first
and then use either a combinatino of <em>v.category</em> + <em>v.to.db</em> or 
<em><a href="wxGUI.vdigit.html">wxGUI vector digitizer</a></em>
to add the relevant lines to the table.
<p>
The supported types of columns depend on the database backend. However, all
backends should support VARCHAR, INT, DOUBLE PRECISION and DATE.
<p>The existing database connection(s) can be verified with <em>v.db.connect</em>.

<h2>EXAMPLE</h2>

Adding a new attribute table with a single column to default layer 1:<br>
<div class="code"><pre>
g.copy vect=roadsmajor,myroads
v.db.addtable myroads columns="slope double precision"
v.db.connect -p myroads
v.info -c myroads
</pre></div>

<p>Adding a new attribute table with two columns to layer 2:<br>
<div class="code"><pre>
g.copy vect=roadsmajor,myroads
v.db.addtable myroads columns="slope double precision, roadname varchar(15)" layer=2
v.db.connect -p myroads
v.info -c myroads
v.info -c myroads layer=2
</pre></div>

<h2>SEE ALSO</h2>

<em>
<a href="db.connect.html">db.connect</a>,
<a href="db.droptable.html">db.droptable</a>,
<a href="db.execute.html">db.execute</a>,
<a href="v.db.addtable.html">v.db.addtable</a>,
<a href="v.db.connect.html">v.db.connect</a>,
<a href="v.db.dropcolumn.html">v.db.dropcolumn</a>,
<a href="v.db.droptable.html">v.db.droptable</a>,
<a href="v.db.select.html">v.db.select</a>,
<a href="v.db.update.html">v.db.update</a><br>
<a href="sql.html">GRASS SQL interface</a>
</em>

<h2>AUTHOR</h2>

Markus Neteler

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