NAME¶

v.db.connect - Prints/sets DB connection for a vector map to attribute table.

KEYWORDS¶

vector, database, attribute table

SYNOPSIS¶

v.db.connect v.db.connect help v.db.connect [-pglcod] map=name [driver=name] [ database=name] [table=name] [ key=name] [layer=integer] [ fs=character] [--verbose] [-- quiet]

Flags:¶

-p

 

Print all map connection parameters and exit

-g

 

Print all map connection parameters and exit in shell script style

 

Format: layer[/layer name] table key database driver

-l

 

When printing, limit to layer specified by the layer option

-c

 

Print types/names of table columns for specified layer and exit

-o

 

Overwrite connection parameter for certain layer

-d

 

Delete connection for certain layer (not the table)

--verbose

 

Verbose module output

--quiet

 

Quiet module output

Parameters:¶

map=name

 

Name of input vector map

driver=name

 

Driver name

 

Options: pg,dbf,ogr,odbc,mysql,sqlite

 

Default: dbf

database=name

 

Database name

 

Default: $GISDBASE/$LOCATION_NAME/$MAPSET/dbf/

table=name

 

Table name

key=name

 

Key column name

 

Must refer to an integer column

 

Default: cat

layer=integer

 

Layer number

 

A single vector map can be connected to multiple database tables. This number determines which table to use.

 

Default: 1

fs=character

 

Field separator

 

Field separator for shell script style output

 

Default:

DESCRIPTION¶

v.db.connect prints or sets database connection for a vector map. The user can add or remove link to attribute table on the certain layer.

NOTE¶

If parameters for database connection are already set with db.connect, they are taken as default values and do not need to be spcified each time. When printing database connection ( p or g flag) the parameter layer is ignored, i.e. all connections are printed to the output, unless l flag is given. Attention: Removing a vector map will also delete all tables linked to it! If you use v.db.connect to link further tables to your map, it is advisable to make a copy from those tables first and connect the copied tables to the vector map (see also v.overlay).

EXAMPLE¶

Print database connection¶

Print all database connection parameters for vector map. v.db.connect -p map=roads Print column types and names of table linked to vector map. v.db.connect -c map=roads

Connect vector map to database (DBF driver)¶

Connect vector map to DBF table without or with variables. Using default DB connection: v.db.connect map=vectormap table=table Using hardcoded path to DBF directory (not recommended): v.db.connect map=vectormap table=table \
database=/home/user/grassdata/spearfish60/PERMANENT/dbf Using variable as DBF directory definition, single quotes must be used: v.db.connect map=vectormap table=table \
database='$GISDBASE/$LOCATION_NAME/$MAPSET/dbf/' Connect vector map layer 2 and key ID to database with variables (note: if needed, single quotes must be used for the database parameter): v.db.connect map=vectormap table=table layer=2 key=ID

Connect vector map to database (SQLite driver)¶

Very similar to DBF driver example above. db.connect driver=sqlite database='$GISDBASE/$LOCATION_NAME/$MAPSET/sqlite.db' db.tables -p v.db.connect map=vectormap table=table driver=sqlite \
database='$GISDBASE/$LOCATION_NAME/$MAPSET/sqlite.db' v.db.connect -p map=vectormap

Connect vector map to database (MySQL driver)¶

# note: connection which requires password db.connect driver=mysql database="host=dbserver.foo.org,dbname=my_database" db.login user=joshua [password=xxx] # ... or enter password interactively. db.tables -p # connect external table to layer 2: v.db.connect map=my_map table=my_mysql_table key=baz layer=2 v.db.connect -p my_map

Connect vector map to database (PostgreSQL driver)¶

# note: connection without password being asked v.db.connect map=vectormap table=table layer=1 key=oid driver=pg \
database="host=myserver.itc.it,dbname=mydb,user=name" \
table=mytable key=id

Store geometry in GRASS but attributes in PostgreSQL¶

This example illustrated a mixed data storage with possibility top update attributes in external PostgreSQL database: # Check current settings for attribute storage: db.connect -p # Import table from PostgreSQL to new map # (NOTE: output map name needs to be different from table name in # case that GRASS is connected to PostgreSQL): v.in.db driver=pg database="host=localhost,dbname=meteo" \
table=mytable x=lon y=lat key=cat out=mytable v.db.connect map=mytable -p # Cancel table connection between map and attribute table: v.db.connect map=mytable -d v.db.connect map=mytable -p # Drop table which was replicated due to import: db.tables -p echo "DROP TABLE mytable" | db.execute db.tables -p # reconnect map to table in PostgreSQL: v.db.connect map=mytable driver=pg database="host=localhost,dbname=meteo" \
table=mytable key=cat # Now the geometry is stored in GRASS while the attributes are stored # in PostgreSQL. An alternative is to create a "view" of only ID, x, y [,z] columns and to use v.in.db on this view, then connect the original table to the geometry. This will be faster if the original table is very large.

Store geometry in GRASS but attributes in PostGIS¶

This example illustrated a mixed data storage with possibility top update attributes in external PostGIS database: # Check current settings for attribute storage: db.connect -p # Import table from PostGIS to new map # (NOTE: output map name needs to be different from table name in # case that GRASS is connected to PostGIS): v.in.db driver=pg database="host=localhost,dbname=meteo" \
table=mytable x="x(geom)" y="y(geom)" key=cat out=mytable v.db.connect map=mytable -p # Cancel table connection between map and attribute table: v.db.connect map=mytable -d v.db.connect map=mytable -p # Drop table which was replicated due to import: db.tables -p echo "DROP TABLE mytable" | db.execute db.tables -p # reconnect map to table in PostGIS: v.db.connect map=mytable driver=pg database="host=localhost,dbname=meteo" \
table=mytable key=cat # Now the geometry is stored in GRASS while the attributes are stored # in PostGIS.

SEE ALSO¶

db.connect, db.copy, db.tables, v.db.addtable, v.db.droptable, v.db.addcol, v.db.dropcol, v.external, v.in.db, v.overlay

AUTHOR¶

Radim Blazek, ITC-Irst, Trento, Italy Last changed: $Date: 2011-11-08 12:29:50 +0100 (Tue, 08 Nov 2011) $ Full index © 2003-2014 GRASS Development Team