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PostgreSQL 8.1.4 Documentation | ||||
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Prev | Fast Backward | Chapter 38. PL/Perl - Perl Procedural Language | Fast Forward | Next |
You can use the global hash %_SHARED to store data, including code references, between function calls for the lifetime of the current session.
Here is a simple example for shared data:
CREATE OR REPLACE FUNCTION set_var(name text, val text) RETURNS text AS $$ if ($_SHARED{$_[0]} = $_[1]) { return 'ok'; } else { return "can't set shared variable $_[0] to $_[1]"; } $$ LANGUAGE plperl; CREATE OR REPLACE FUNCTION get_var(name text) RETURNS text AS $$ return $_SHARED{$_[0]}; $$ LANGUAGE plperl; SELECT set_var('sample', 'Hello, PL/Perl! How's tricks?'); SELECT get_var('sample');
Here is a slightly more complicated example using a code reference:
CREATE OR REPLACE FUNCTION myfuncs() RETURNS void AS $$ $_SHARED{myquote} = sub { my $arg = shift; $arg =~ s/(['\\])/\\$1/g; return "'$arg'"; }; $$ LANGUAGE plperl; SELECT myfuncs(); /* initializes the function */ /* Set up a function that uses the quote function */ CREATE OR REPLACE FUNCTION use_quote(TEXT) RETURNS text AS $$ my $text_to_quote = shift; my $qfunc = $_SHARED{myquote}; return &$qfunc($text_to_quote); $$ LANGUAGE plperl;
(You could have replaced the above with the one-liner return $_SHARED{myquote}->($_[0]); at the expense of readability.)