1databaseintro(1) GRASS GIS User's Manual databaseintro(1)
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6 Attribute management in general
7 GRASS can be linked to one or many database management systems (DBMS).
8 The db.* set of commands provides basic SQL support for attribute man‐
9 agement, while the v.db.* set of commands operates on the vector map
10 (see Vector introduction).
11 Available drivers
13 Available drivers are listed in SQL support in GRASS GIS.
14 Notes:
16 The DBF driver provides only very limited SQL support (as DBF is not an
17 SQL DB) while the other DBMS backends (such as SQLite, PostgreSQL,
18 MySQL etc) provide full SQL support since the SQL commands are sent di‐
19 rectly to the DBMS. For this reason, the SQLite driver is the default
20 DBMI backend.
21 DB connection management
23 The current database management settings are shown or modified with
24 db.connect for current mapset. Available DBMI drivers are listed with
25 db.drivers. Some DBMI backends require a user/password for driver/data‐
26 base to be set with db.login. In order to test a driver, run db.test.
27 Attribute data import and export
29 Attribute data can be imported with db.in.ogr from various formats and
30 exported with db.out.ogr. To internally copy a a full table or selec‐
31 tively parts of it, use db.copy.
32 Further conversion tools:
34 • MDB Tools: Convert MS-Access data to SQL, DBF, etc.
36 • Using OpenOffice.org with SQL Databases
38 SQL commands
40 GRASS supports two main SQL operations, execution of an SQL statement
41 (db.execute) and selection of data from a table (db.select). See the
42 SQL help page for examples.
43 Managing the default DBMI settings
45 Per default vector map attributes are stored in SQLite tables. This de‐
46 fault definition can be modified with db.connect. If an external DBMS
47 is used, db.login may be required.
48 Creating a database
50 Specific commands are explained on the individual driver pages (these
51 pages are only available if driver was compiled in this installation):
52 • DBF: see DBF page
54 • SQLite: SQLite page
56 • mySQL: mySQL and meSQL pages
58 • ODBC: ODBC page (connect to Oracle, etc.)
60 • PostgreSQL: PostgreSQL and PostGIS page
62 Metadata
64 All columns for a given table are listed with db.columns. The command
65 db.describe describes a table in detail. To list all available tables
66 for a given database, run db.tables.
67 Table maintenance
69 To drop a column from a selected attribute table, use db.dropcolumn.
70 With db.droptable an attribute table can be deleted.
71 Database Schema
73 Currently schema support only works for PostgreSQL connections. Default
74 schema can be set with db.connect. Note that the default schema will be
75 used by all db.* modules.
76 db.tables returns ’schema.table’ if schemas are available in the data‐
78 base.
79 Migrating to a different database engine
81 To migrate a GRASS database table (or a GRASS vector map) to a differ‐
82 ent DBMI engine, the best solution is to create a new MAPSET, define
83 the DBMI settings accordingly with db.connect and if needed, db.login.
84 Then the table of interest can be copied over with db.copy from the
85 original MAPSET. Likewise, a vector map including its table(s) are
86 copied from the original MAPSET to the current MAPSET with g.copy.
87 See also
89 • Introduction into raster data processing
90 • Introduction into 3D raster data (voxel) processing
92 • Introduction into vector data processing
94 • Introduction into image processing
96 • Introduction into temporal data processing
98 • Projections and spatial transformations
100
102 Available at: Database management in GRASS GIS source code (history)
103 Accessed: Fri Jun 3 13:27:06 2022
105 Main index | Database index | Topics index | Keywords index | Graphical
107 index | Full index
108 © 2003-2022 GRASS Development Team, GRASS GIS 8.2.0 Reference Manual
110GRASS 8.2.0 databaseintro(1)