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This commit is contained in:
Peter Eisentraut
2002-01-07 02:29:15 +00:00
parent a510bf4326
commit 731204e090
35 changed files with 1383 additions and 1320 deletions
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48
doc/src/sgml/plperl.sgml
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@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/plperl.sgml,v 2.11 2001/11/21 05:53:41 thomas Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/plperl.sgml,v 2.12 2002/01/07 02:29:13 petere Exp $
-->
<chapter id="plperl">
@ -13,15 +13,19 @@ $Header: /cvsroot/pgsql/doc/src/sgml/plperl.sgml,v 2.11 2001/11/21 05:53:41 thom
<primary>Perl</primary>
</indexterm>
<sect1 id="intro">
<title>Introduction</title>
<para>
PL/Perl allows you to write functions in the Perl programming
language that may be used in SQL queries as if they were built into
PL/Perl allows you to write functions in the <ulink
url="http://www.perl.com">Perl</ulink> programming language that may
be used in SQL queries as if they were built into
<productname>PostgreSQL</productname>.
</para>
<para>
The PL/Perl interpreter (when installed as trusted interpreter with
default name <literal>plperl</>) interpreter is a full Perl interpreter. However, certain
default name <literal>plperl</>) is a full Perl interpreter. However, certain
operations have been disabled in order to maintain the security of
the system. In general, the operations that are restricted are
those that interact with the environment. This includes file handle
@ -33,8 +37,9 @@ $Header: /cvsroot/pgsql/doc/src/sgml/plperl.sgml,v 2.11 2001/11/21 05:53:41 thom
</para>
<para>
When PL/Perl is installed as <quote>untrusted</> interpreter (with name <literal>plperlu</literal>),
everything is permitted, and any Perl code can be loaded (by superuser only).
everything is permitted, and any Perl code can be loaded (by a superuser only).
</para>
</sect1>
<sect1 id="plperl-install">
<title>Building and Installing</title>
@ -54,10 +59,9 @@ $Header: /cvsroot/pgsql/doc/src/sgml/plperl.sgml,v 2.11 2001/11/21 05:53:41 thom
fact:
<screen>
<computeroutput>
*****
* Cannot build PL/Perl because libperl is not a shared library.
* Skipped.
*****
*** Cannot build PL/Perl because libperl is not a shared library.
*** You might have to rebuild your Perl installation. Refer to
*** the documentation for details.
</computeroutput>
</screen>
Therefore it is likely that you will have to re-build and install
@ -84,7 +88,7 @@ gmake install
<prompt>$</prompt> <userinput>createlang plperl template1</userinput>
</screen>
Alternatively, to create untrusted interpreter (where functions can only
be created by superuser, but the functions are not restricted), use:
be created by a superuser, but the functions are not restricted), use:
<screen>
<prompt>$</prompt> <userinput>createlang plperlu template1</userinput>
</screen>
@ -99,7 +103,7 @@ be created by superuser, but the functions are not restricted), use:
<para>
Assume you have the following table:
<programlisting>
CREATE TABLE EMPLOYEE (
CREATE TABLE employee (
name text,
basesalary integer,
bonus integer
@ -111,7 +115,7 @@ CREATE TABLE EMPLOYEE (
<programlisting>
CREATE FUNCTION totalcomp(integer, integer) RETURNS integer
AS 'return $_[0] + $_[1]'
LANGUAGE 'plperl';
LANGUAGE plperl;
</programlisting>
Notice that the arguments to the function are passed in
@ -131,7 +135,7 @@ SELECT name, totalcomp(basesalary, bonus) FROM employee;
CREATE FUNCTION empcomp(employee) RETURNS integer AS '
my $emp = shift;
return $emp->{''basesalary''} + $emp->{''bonus''};
' LANGUAGE 'plperl';
' LANGUAGE plperl;
</programlisting>
A tuple is passed as a reference to a hash. The keys are the names
of the fields in the tuples. The hash values are values of the
@ -151,7 +155,7 @@ CREATE FUNCTION empcomp(employee) RETURNS integer AS '
</tip>
<para>
The new function <function>empcomp</function> can used like:
The new function <function>empcomp</function> can be used like:
<programlisting>
SELECT name, empcomp(employee) FROM employee;
</programlisting>
@ -165,18 +169,22 @@ CREATE FUNCTION badfunc() RETURNS integer AS '
open(TEMP, ">/tmp/badfile");
print TEMP "Gotcha!\n";
return 1;
' LANGUAGE 'plperl';
' LANGUAGE plperl;
</programlisting>
The creation of the function will succeed, but executing it will not.
</para>
<para>
Note that if same function was created by superuser using language
<literal>plperlu</>, execution would succeed.
</para>
<para>
Access to database itself from your Perl function can be done via
an experimental module <ulink url="http://www.formenos.org/PgSPI/"><literal>DBD::PgSPI</literal></ulink>. This module makes available a <acronym>DBI</>-compliant
database-handle named <varname>$pg_dbh</varname>, and you can use that to make queries with
normal <acronym>DBI</> syntax.
Access to database itself from your Perl function can be done via
an experimental module <ulink
url="http://www.formenos.org/PgSPI/"><literal>DBD::PgSPI</literal></ulink>
(also on <ulink url="http://www.cpan.org">CPAN</ulink>). This
module makes available a <acronym>DBI</>-compliant database-handle
named <varname>$pg_dbh</varname>, and you can use that to perform
queries with normal <acronym>DBI</> syntax.
</para>
</sect1>