Section: Tcl Database Connectivity (n)
Updated: 8.6
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tdbc::postgres - TDBC-POSTGRES bridge  


package require tdbc::postgres 1.0

tdbc::postgres::connection create db ?-option value...?
tdbc::postgres::connection new ?-option value...?



The tdbc::postgres driver provides a database interface that conforms to Tcl DataBase Connectivity (TDBC) and allows a Tcl script to connect to a Postgres database.

Connection to a POSTGRES database is established by invoking tdbc::postgres::connection create, passing it the name to give the database handle and a set of -option-value pairs. The available options are enumerated under CONNECTION OPTIONS below. As an alternative, tdbc::postgres::connection new may be used to create a database connection with an automatically assigned name. The return value from tdbc::postgres::connection new is the name that was chosen for the connection handle.

The side effect of tdbc::postgres::connection create is to create a new database connection.. See tdbc::connection(n) for the details of how to use the connection to manipulate a database.  


The tdbc::postgres::connection create object command supports the -encoding, -isolation, -readonly and -timeout options common to all TDBC drivers. The -timeout option will only affect connection process, once connected this value will be ignored and cannot be changed after connecting.

In addition, the following options are recognized (these options must be set on the initial creation of the connection; they cannot be changed after connecting) :

-host hostname
Connects to the host specified by hostname. Default is to connect using a local Unix domain socket.
-hostaddr address
Connects to the host specified by given IP address. If both -host and -hostaddr are given, the value of -host is ignored. Default is to connect using a local Unix domain socket.
-port number
Connects to a Postgres server listening on the port specified by number. It is used only when host or hostaddr is specified.
-user name
Presents name as the user name to the Postgres server. Default is the current user ID.
-passwd password
-password password
These two options are synonymous. They present the given password as the user's password to the Postgres server. Default is not to present a password.
-database name
-db name
These two options are synonymous. They present the given name as the name of the default database to use in Postgres queries. If not specified, the default database for the current user is used.
-options opts
This sets opts as additional command line options send to the server.
-tty file
This option is ignored on never servers. Formerly this specified where to send debug output. This option is left for compatibility with older servers.
-sslmode mode
This option determines whether or with what priority an SSL connection will be negotiated with the server. There are four modes: disable will attempt only an unencrypted SSL connection; allow will negotiate, trying first a non-SSL connection, then if that fails, trying an SSL connection; prefer (the default) will negotiate, trying first an SSL connection, then if that fails, trying a regular non-SSL connection; require will try only an SSL connection. If PostgreSQL is compiled without SSL support, using option require will cause an error, and options allow and prefer will be tolerated but the driver will be unable to negotiate an SSL connection.
This option is deprecated in favor of the -sslmode setting. The flag value must be a Boolean value. If it is true (or any equivalent), driver will then refuse to connect if the server does not accept an SSL connection. The default value is false (or any equivalent), and acts the same like -sslmode preffered
It specifies a service name in pg_service.conf file that holds additional connection parameters. This allows applications to specify only a service name so connection parameters can be centrally maintained. Refer to PostgreSQL Documentation or PREFIX/share/pg_service.conf.sample file for details.


tdbc::postgres::connection -user joe -passwd sesame -db joes_database

Connects to the Postgres server on the local host using the default connection method, presenting user ID 'joe' and password 'sesame'. Uses 'joes_database' as the default database name.  


tdbc(n), tdbc::connection(n), tdbc::resultset(n), tdbc::statement(n)  


TDBC, SQL, Postgres, database, connectivity, connection  


Copyright (c) 2009 by Slawomir Cygan