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Chapter 4. pgtcl - TCL Binding Library

Table of Contents
4.1. Commands
4.2. Examples
4.3. pgtcl Command Reference Information
pg_connect -- opens a connection to the backend server
pg_disconnect -- closes a connection to the backend server
pg_conndefaults -- obtain information about default connection parameters
pg_exec -- send a query string to the backend
pg_result -- get information about a query result
pg_select -- loop over the result of a SELECT statement
pg_listen -- sets or changes a callback for asynchronous NOTIFY messages
pg_lo_creat -- create a large object
pg_lo_open -- open a large object
pg_lo_close -- close a large object
pg_lo_read -- read a large object
pg_lo_write -- write a large object
pg_lo_lseek -- seek to a position in a large object
pg_lo_tell -- return the current seek position of a large object
pg_lo_unlink -- delete a large object
pg_lo_import -- import a large object from a Unix file
pg_lo_export -- export a large object to a Unix file

pgtcl is a tcl package for front-end programs to interface with Postgres backends. It makes most of the functionality of libpq available to tcl scripts.

This package was originally written by Jolly Chen.

4.1. Commands

Table 4-1. pgtcl Commands

Command Description
pg_connect opens a connection to the backend server
pg_disconnect closes a connection
pg_conndefaults get connection options and their defaults
pg_exec send a query to the backend
pg_result manipulate the results of a query
pg_select loop over the result of a SELECT statement
pg_listen establish a callback for NOTIFY messages
pg_lo_creat create a large object
pg_lo_open open a large object
pg_lo_close close a large object
pg_lo_read read a large object
pg_lo_write write a large object
pg_lo_lseek seek to a position in a large object
pg_lo_tell return the current seek position of a large object
pg_lo_unlink delete a large object
pg_lo_import import a Unix file into a large object
pg_lo_export export a large object into a Unix file

These commands are described further on subsequent pages.

The pg_lo* routines are interfaces to the Large Object features of Postgres. The functions are designed to mimic the analogous file system functions in the standard Unix file system interface. The pg_lo* routines should be used within a BEGIN/END transaction block because the file descriptor returned by pg_lo_open is only valid for the current transaction. pg_lo_import and pg_lo_export MUST be used in a BEGIN/END transaction block.