SpatiaLite

Spatialite

A SQLite database with geospatial extensions, much list PostGIS is to PostgreSQL. To export a layer to a Spatialite database with v.out.ogr, use the SQLite OGR driver and set the SPATIALITE data creation option to "yes".

New database

 v.out.ogr in=mymap output=mydbase.sqlite format=SQLite \
   type=area dsco='SPATIALITE=yes' output_layer="mymap"

Existing spatialite database

Note that you need to use --overwrite, otherwise v.out.ogr will complain that the output already exists. Using --overwrite should maintain the existing tables in the spatialite database. However, it is strongly suggested to run this on a copy of the database, or make sure you have a recent backup.

 v.out.ogr -u in=mymap output=mydbase.sqlite format=SQLite \
   type=area dsco='SPATIALITE=yes' output_layer="mymap" --overwrite

Using QGIS (1)

An alternate way is to load the layer in QGIS's GRASS toolbox, then right click on the layer name and select "Save As...".

Using QGIS (2)

Open the layer in QGIS using the browser panel. Next, open the spatialite database in the QGIS DB manager and use the 'import layer' option to import the grass vector layer you just opened in QGIS into the spatialite database.