## NAME

v.db.addtable - Creates and connects a new attribute table to a given layer of an existing vector map.

## KEYWORDS

vector, attribute table, database

## SYNOPSIS

v.db.addtable
v.db.addtable --help
v.db.addtable map=name [table=string] [layer=integer] [key=name] [columns=name type[,name type,...]] [--help] [--verbose] [--quiet] [--ui]

### Flags:

--help
  Print usage summary
--verbose
  Verbose module output
--quiet
  Quiet module output
--ui
  Force launching GUI dialog

### Parameters:

map=name [required]
  Name of vector map
  Or data source for direct OGR access
table=string
  Name of new attribute table (default: vector map name)
layer=integer
  Layer number where to add new attribute table
  Default: 1
key=name
  Name of key column
  Must refer to an integer column
  Default: cat
columns=name type[,name type,...]
  Name and type of the new column(s) ('name type [,name type, ...]')
  Types depend on database backend, but all support VARCHAR(), INT, DOUBLE PRECISION and DATE. Example: 'label varchar(250), value integer'

## DESCRIPTION

v.db.addtable 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 db.connect).

## NOTES

v.db.addtable is a front-end to db.execute to allow easier usage.

v.db.addtable 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 v.category or manually with wxGUI vector digitizer before running v.db.addtable. Or one can run v.db.addtable first and then use either a combinatino of v.category + v.to.db or wxGUI vector digitizer to add the relevant lines to the table.

The supported types of columns depend on the database backend. However, all backends should support VARCHAR, INT, DOUBLE PRECISION and DATE.

The existing database connection(s) can be verified with v.db.connect.

## EXAMPLE

Adding a new attribute table with a single column to default layer 1:

    g.copy vect=roadsmajor,myroads
    v.db.addtable myroads columns="slope double precision"
    v.db.connect -p myroads
    v.info -c myroads

Adding a new attribute table with two columns to layer 2:

    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

## SEE ALSO

db.connect, db.droptable, db.execute, v.db.connect, v.db.dropcolumn, v.db.droptable, v.db.select, v.db.update

GRASS SQL interface

## AUTHOR

Markus Neteler

## SOURCE CODE

Available at: v.db.addtable source code (history)

Accessed: Monday Apr 01 03:09:30 2024

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