v.db.connect(1grass)

1v.db.connect(1)             GRASS GIS User's Manual            v.db.connect(1)
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NAME

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

10       vector, attribute table, database, layer
11

SYNOPSIS

13       v.db.connect
14       v.db.connect --help
15       v.db.connect [-pgcod] map=name  [driver=name]   [database=name]    [ta‐
16       ble=name]      [key=name]      [layer=string]     [separator=character]
17       [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]
18
19   Flags:
20       -p
21           Print all map connection parameters and exit
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23       -g
24           Print all map connection parameters in shell script style and exit
25           Format: layer[/layer name] table key database driver
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27       -c
28           Print types/names of table columns for specified layer and exit
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30       -o
31           Overwrite connection parameter for certain layer
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33       -d
34           Delete connection for certain layer (not the table)
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36       --overwrite
37           Allow output files to overwrite existing files
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39       --help
40           Print usage summary
41
42       --verbose
43           Verbose module output
44
45       --quiet
46           Quiet module output
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48       --ui
49           Force launching GUI dialog
50
51   Parameters:
52       map=nameÂ [required]
53           Name of vector map
54           Or data source for direct OGR access
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56       driver=name
57           Name of database driver
58           Options: dbf, mesql, mysql, odbc, ogr, pg, sqlite
59           Default: sqlite
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61       database=name
62           Name of database
63           Default: $GISDBASE/$LOCATION_NAME/$MAPSET/sqlite/sqlite.db
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65       table=name
66           Name of attribute table
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68       key=name
69           Name of key column
70           Must refer to an integer column
71           Default: cat
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73       layer=string
74           Layer number or name
75           Format: layer number[/layer name]
76           Default: 1
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78       separator=character
79           Field separator for shell script style output
80           Special characters: pipe, comma, space, tab, newline
81           Default: pipe
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DESCRIPTION

84       v.db.connect prints or sets database connection for a vector  map.  The
85       user can add or remove link to attribute table on the certain layer.
86

NOTE

88       Connection  information  (driver,  database,  table, key) is stored for
89       each map, in the file
90       <database>/<location>/<mapset>/vector/<map>/dbln
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92       If parameters for database connection are already set with  db.connect,
93       they  are  taken as default values and do not need to be specified each
94       time.
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96       When printing database connection (p or g flag) the parameter layer  is
97       ignored, i.e. all connections are printed to the output.
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99       Attention:  Removing a vector map will also delete all tables linked to
100       it! If you use v.db.connect to link further tables to your map,  it  is
101       advisable to make a copy from those tables first and connect the copied
102       tables to the vector map (see also v.overlay).
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EXAMPLE

105       Note: The default database backend setting is SQLite.
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107   Print database connection
108       Print all database connection parameters for vector map.
109       v.db.connect -p map=roads
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111       Print column types and names of table linked to vector map.
112       v.db.connect -c map=roads
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114   Connect vector map to database (DBF driver)
115       Connect vector map to DBF table without or with variables.
116
117       Using default DB connection:
118       v.db.connect map=vectormap table=table
119
120       Using hardcoded path to DBF directory (not recommended):
121       v.db.connect map=vectormap table=table \
122                    database=/home/user/grassdata/spearfish60/PERMANENT/dbf
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124       Using variable as DBF directory definition, single quotes must be used:
125       v.db.connect map=vectormap table=table \
126                    database=’$GISDBASE/$LOCATION_NAME/$MAPSET/dbf/’
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128       Connect vector map layer 2 and key ID to database with variables (note:
129       if needed, single quotes must be used for the database parameter):
130       v.db.connect map=vectormap table=table layer=2 key=ID
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132   Connect vector map to database (SQLite driver)
133       Very similar to DBF driver example above.
134       db.connect driver=sqlite database=’$GISDBASE/$LOCATION_NAME/$MAPSET/sqlite/sqlite.db’
135       db.tables -p
136       v.db.connect map=vectormap table=table driver=sqlite \
137                    database=’$GISDBASE/$LOCATION_NAME/$MAPSET/sqlite/sqlite.db’
138       v.db.connect -p map=vectormap
139
140   Connect vector map to database (MySQL driver)
141       # note: connection which requires password
142       db.connect driver=mysql database="host=dbserver.foo.org,dbname=my_database"
143       db.login user=joshua [password=xxx]
144       # ... or enter password interactively.
145       db.tables -p
146       # connect external table to layer 2:
147       v.db.connect map=my_map table=my_mysql_table key=baz layer=2
148       v.db.connect -p my_map
149
150   Connect vector map to database (PostgreSQL driver)
151       # note: connection without password being asked
152       v.db.connect map=vectormap table=table layer=1 key=oid driver=pg \
153                    database="host=myserver.itc.it,dbname=mydb,user=name" \
154                    table=mytable key=id
155
156   Store geometry in GRASS but attributes in PostgreSQL
157       This  example  illustrates a mixed data storage with possibility to up‐
158       date attributes in an external PostgreSQL database:
159       # Check current settings for attribute storage:
160       db.connect -p
161       # Import table from PostgreSQL to new map
162       # (NOTE: output map name needs to be different from table name in
163       #        case that GRASS is connected to PostgreSQL):
164       v.in.db driver=pg database="host=localhost,dbname=meteo" \
165               table=mytable x=lon y=lat key=cat out=mytable
166       v.db.connect map=mytable -p
167       # Cancel table connection between map and attribute table:
168       v.db.connect map=mytable -d
169       v.db.connect map=mytable -p
170       # Drop table which was replicated due to import:
171       db.tables -p
172       echo "DROP TABLE mytable" | db.execute
173       db.tables -p
174       # reconnect map to table in PostgreSQL:
175       v.db.connect map=mytable driver=pg database="host=localhost,dbname=meteo" \
176               table=mytable key=cat
177       # Now the geometry is stored in GRASS while the attributes are stored
178       # in PostgreSQL.
179       An alternative is to create a "view" of only ID, x, y [,z] columns  and
180       to use v.in.db on this view, then connect the original table to the ge‐
181       ometry. This will be faster if the original table is very large.
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183   Store geometry in GRASS but attributes in PostGIS
184       This example illustrated a mixed data storage with possibility top  up‐
185       date attributes in external PostGIS database:
186       # Check current settings for attribute storage:
187       db.connect -p
188       # Import table from PostGIS to new map
189       # (NOTE: output map name needs to be different from table name in
190       #        case that GRASS is connected to PostGIS):
191       v.in.db driver=pg database="host=localhost,dbname=meteo" \
192               table=mytable x="x(geom)" y="y(geom)" key=cat out=mytable
193       v.db.connect map=mytable -p
194       # Cancel table connection between map and attribute table:
195       v.db.connect map=mytable -d
196       v.db.connect map=mytable -p
197       # Drop table which was replicated due to import:
198       db.tables -p
199       echo "DROP TABLE mytable" | db.execute
200       db.tables -p
201       # reconnect map to table in PostGIS:
202       v.db.connect map=mytable driver=pg database="host=localhost,dbname=meteo" \
203               table=mytable key=cat
204       # Now the geometry is stored in GRASS while the attributes are stored
205       # in PostGIS.
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AUTHOR

214       Radim Blazek, ITC-Irst, Trento, Italy
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SOURCE CODE

217       Available at: v.db.connect source code (history)
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219       Accessed: Saturday Jan 21 21:15:55 2023
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221       Main index | Vector index | Topics index | Keywords index  |  Graphical
222       index | Full index
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224       Â© 2003-2023 GRASS Development Team, GRASS GIS 8.2.1 Reference Manual
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228GRASS 8.2.1                                                    v.db.connect(1)