PostgreSQL, Second Edition

Client 2—Query Processing

Executing a command with libpgtcl is easy. You invoke the pg_exec procedure and you get back a result handle. pg_exec expects two parameters:

pg_exec connection_handle command

A typical call to pg_exec might look like this:

set result_handle [pg_exec $conn "SELECT * FROM customers"]

Calling pg_exec like this captures the result handle in the variable result_handle. A result handle encapsulates many items of information into a single object. You can't get at any of this information directly; instead, you have to use the pg_result procedure.

Result Set Processing

Let's look at some of the things that you can do with a result handle:

 $ tclsh % package require Pgtcl % set connstr "host=davinci user=korry password=cows ...