t.connect - GRASS manual

NAME

t.connect - Prints/sets general temporal GIS database connection for current mapset.

KEYWORDS

SYNOPSIS

t.connect

t.connect --help

t.connect [-pcdg] [format=name] [driver=name] [database=name] [mapset=name[,name,...]] [--help] [--verbose] [--quiet] [--ui]

Flags:

-p: Print current connection parameters and exit
-c: Check connection parameters, set if uninitialized, and exit
-d: Set from default settings and exit; Overwrite current settings if initialized
-g: Print current connection parameters using shell style and exit [deprecated]; This flag is deprecated and will be removed in a future release. Use format=shell instead.
--help: Print usage summary
--verbose: Verbose module output
--quiet: Quiet module output
--ui: Force launching GUI dialog

Parameters:

format=name: Output format; Options: plain, shell, json; Default: plain; plain: Plain text output; shell: Shell script style output; json: JSON (JavaScript Object Notation)
driver=name: Name of database driver; Options: sqlite, pg; Default: sqlite
database=name: Name of database; Default: $GISDBASE/$LOCATION_NAME/$MAPSET/tgis/sqlite.db
mapset=name[,name,...]: Name of the mapset(s) to print the connection info for; '.' for current mapset; '*' for all mapsets in the project. Requires format=json.

DESCRIPTION
NOTES
EXAMPLES
- SQLite
- PostgreSQL
AUTHOR

DESCRIPTION

t.connect allows the user to set or print the temporal database connection.

The default setting is that the temporal database uses the sqlite backend, where the path to the SQLite database is set to "tgis/sqlite.db" in the current mapset directory. That way it will not interfere with the sqlite database used for vector attribute storage.

The -p flag will display the current temporal database connection parameters.

The -pg flag will display the current temporal database connection parameters using shell style.

The -c flag will silently check if the temporal database connection parameters have been set, and if not will set them to use GRASS's default values.

The -d flag will set the default TGIS connection parameters.

NOTES

Setting the connection with t.connect will only store connection values in the mapset's `VAR` file. It will not test the connection for validity. Hence a database connection will not be established. Neither will t.connect create the temporal database. The temporal database will be created by the first run of a tool that creates SpaceTimeDataSets (STDS), either based on connection values set by t.connect or - if not defined - the global default (sqlite).

In case you have tens of thousands of maps to register in the temporal database or you need concurrent read and write access in the temporal database, consider to use a PostgreSQL connection instead.

Be aware that you have to set the PostgreSQL connection explicitly in every mapset that should store temporal information in the temporal database.

PostgreSQL and SQLite databases can not be mixed in a project.

EXAMPLES

SQLite

The SQLite database is created automatically when used the first time.

# use single quotes here
t.connect driver=sqlite database='$GISDBASE/$LOCATION_NAME/PERMANENT/tgis/sqlite.db'
t.connect -p
t.info -s

PostgreSQL

When using a PostgreSQL database, the user will need to specify the TGIS database connection for each mapset.

t.connect driver=pg database="dbname=grass_test user=soeren password=abcdefgh"
t.connect -p
t.info -s

AUTHOR

Soeren Gebbert, Thünen Institute of Climate-Smart Agriculture

SOURCE CODE

Available at: t.connect source code (history)

Latest change: Wednesday Jul 15 15:59:47 2026 in commit: 9893d6817d3900835ff0e0775132f773ae547f0f