mirror of
https://github.com/postgres/postgres.git
synced 2025-05-02 11:44:50 +03:00
Backpatch documentation additions for PL language choice and
regex_replace() to 8.1.X.
This commit is contained in:
Bruce Momjian
parent
b71b22d901
commit
401ffe0555
@ -1,5 +1,5 @@
|
||||
<!--
|
||||
$PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.291.2.5 2005/12/21 23:23:09 momjian Exp $
|
||||
$PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.291.2.6 2006/05/30 12:32:37 momjian Exp $
|
||||
PostgreSQL documentation
|
||||
-->
|
||||
|
||||
@ -1107,7 +1107,9 @@ PostgreSQL documentation
|
||||
<entry><literal><function>substring</function>(<parameter>string</parameter> from <replaceable>pattern</replaceable>)</literal></entry>
|
||||
<entry><type>text</type></entry>
|
||||
<entry>
|
||||
Extract substring matching POSIX regular expression
|
||||
Extract substring matching POSIX regular expression. See
|
||||
<xref linkend="functions-matching"> for more information on pattern
|
||||
matching.
|
||||
</entry>
|
||||
<entry><literal>substring('Thomas' from '...$')</literal></entry>
|
||||
<entry><literal>mas</literal></entry>
|
||||
@ -1117,8 +1119,9 @@ PostgreSQL documentation
|
||||
<entry><literal><function>substring</function>(<parameter>string</parameter> from <replaceable>pattern</replaceable> for <replaceable>escape</replaceable>)</literal></entry>
|
||||
<entry><type>text</type></entry>
|
||||
<entry>
|
||||
Extract substring matching <acronym>SQL</acronym> regular
|
||||
expression
|
||||
Extract substring matching <acronym>SQL</acronym> regular expression.
|
||||
See <xref linkend="functions-matching"> for more information on
|
||||
pattern matching.
|
||||
</entry>
|
||||
<entry><literal>substring('Thomas' from '%#"o_a#"_' for '#')</literal></entry>
|
||||
<entry><literal>oma</literal></entry>
|
||||
@ -1416,6 +1419,18 @@ PostgreSQL documentation
|
||||
<entry><literal>'O''Reilly'</literal></entry>
|
||||
</row>
|
||||
|
||||
<row>
|
||||
<entry><literal><function>regexp_replace</function>(<parameter>string</parameter> <type>text</type>, <parameter>pattern</parameter> <type>text</type>, <parameter>replacement</parameter> <type>text</type> [,<parameter>flags</parameter> <type>text</type>])</literal></entry>
|
||||
<entry><type>text</type></entry>
|
||||
<entry>
|
||||
Replace substring matching POSIX regular expression. See
|
||||
<xref linkend="functions-matching"> for more information on pattern
|
||||
matching.
|
||||
</entry>
|
||||
<entry><literal>regexp_replace('Thomas', '.[mN]a.', 'M')</literal></entry>
|
||||
<entry><literal>ThM</literal></entry>
|
||||
</row>
|
||||
|
||||
<row>
|
||||
<entry><literal><function>repeat</function>(<parameter>string</parameter> <type>text</type>, <parameter>number</parameter> <type>int</type>)</literal></entry>
|
||||
<entry><type>text</type></entry>
|
||||
|
||||
@ -1,5 +1,5 @@
|
||||
<!--
|
||||
$PostgreSQL: pgsql/doc/src/sgml/plperl.sgml,v 2.49 2005/11/04 23:14:00 petere Exp $
|
||||
$PostgreSQL: pgsql/doc/src/sgml/plperl.sgml,v 2.49.2.1 2006/05/30 12:32:37 momjian Exp $
|
||||
-->
|
||||
|
||||
<chapter id="plperl">
|
||||
@ -19,6 +19,12 @@ $PostgreSQL: pgsql/doc/src/sgml/plperl.sgml,v 2.49 2005/11/04 23:14:00 petere Ex
|
||||
<ulink url="http://www.perl.com">Perl programming language</ulink>.
|
||||
</para>
|
||||
|
||||
<para> The usual advantage to using PL/Perl is that this allows use,
|
||||
within stored functions, of the manyfold <quote>string
|
||||
munging</quote> operators and functions available for Perl. Parsing
|
||||
complex strings may be be easier using Perl than it is with the
|
||||
string functions and control structures provided in PL/pgsql.</para>
|
||||
|
||||
<para>
|
||||
To install PL/Perl in a particular database, use
|
||||
<literal>createlang plperl <replaceable>dbname</></literal>.
|
||||
|
||||
@ -1,5 +1,5 @@
|
||||
<!--
|
||||
$PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.80.2.4 2006/02/05 02:48:20 momjian Exp $
|
||||
$PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.80.2.5 2006/05/30 12:32:37 momjian Exp $
|
||||
-->
|
||||
|
||||
<chapter id="plpgsql">
|
||||
@ -157,21 +157,36 @@ $$ LANGUAGE plpgsql;
|
||||
|
||||
<para>
|
||||
That means that your client application must send each query to
|
||||
the database server, wait for it to be processed, receive the
|
||||
results, do some computation, then send other queries to the
|
||||
server. All this incurs interprocess communication and may also
|
||||
incur network overhead if your client is on a different machine
|
||||
than the database server.
|
||||
the database server, wait for it to be processed, receive and
|
||||
process the results, do some computation, then send further
|
||||
queries to the server. All this incurs interprocess
|
||||
communication and will also incur network overhead if your client
|
||||
is on a different machine than the database server.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
With <application>PL/pgSQL</application> you can group a block of computation and a
|
||||
series of queries <emphasis>inside</emphasis> the
|
||||
database server, thus having the power of a procedural
|
||||
language and the ease of use of SQL, but saving lots of
|
||||
time because you don't have the whole client/server
|
||||
communication overhead. This can make for a
|
||||
considerable performance increase.
|
||||
With <application>PL/pgSQL</application> you can group a block of
|
||||
computation and a series of queries <emphasis>inside</emphasis>
|
||||
the database server, thus having the power of a procedural
|
||||
language and the ease of use of SQL, but with considerable
|
||||
savings because you don't have the whole client/server
|
||||
communication overhead.
|
||||
</para>
|
||||
<itemizedlist>
|
||||
|
||||
<listitem><para> Elimination of additional round trips between
|
||||
client and server </para></listitem>
|
||||
|
||||
<listitem><para> Intermediate results that the client does not
|
||||
need do not need to be marshalled or transferred between server
|
||||
and client </para></listitem>
|
||||
|
||||
<listitem><para> There is no need for additional rounds of query
|
||||
parsing </para></listitem>
|
||||
|
||||
</itemizedlist>
|
||||
<para> This can allow for a considerable performance increase as
|
||||
compared to an application that does not use stored functions.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
|
||||
@ -1,5 +1,5 @@
|
||||
<!--
|
||||
$PostgreSQL: pgsql/doc/src/sgml/pltcl.sgml,v 2.38 2005/05/20 01:52:25 neilc Exp $
|
||||
$PostgreSQL: pgsql/doc/src/sgml/pltcl.sgml,v 2.38.2.1 2006/05/30 12:32:37 momjian Exp $
|
||||
-->
|
||||
|
||||
<chapter id="pltcl">
|
||||
@ -27,22 +27,27 @@ $PostgreSQL: pgsql/doc/src/sgml/pltcl.sgml,v 2.38 2005/05/20 01:52:25 neilc Exp
|
||||
<title>Overview</title>
|
||||
|
||||
<para>
|
||||
PL/Tcl offers most of the capabilities a function
|
||||
writer has in the C language, except for some restrictions.
|
||||
PL/Tcl offers most of the capabilities a function writer has in
|
||||
the C language, with a few restrictions, and with the addition of
|
||||
the powerful string processing libraries that are available for
|
||||
Tcl.
|
||||
</para>
|
||||
<para>
|
||||
The good restriction is that everything is executed in a safe
|
||||
Tcl interpreter. In addition to the limited command set of safe Tcl, only
|
||||
a few commands are available to access the database via SPI and to raise
|
||||
messages via <function>elog()</>. There is no way to access internals of the
|
||||
database server or to gain OS-level access under the permissions of the
|
||||
<productname>PostgreSQL</productname> server process, as a C function can do.
|
||||
Thus, any unprivileged database user may be
|
||||
permitted to use this language.
|
||||
One compelling <emphasis>good</emphasis> restriction is that
|
||||
everything is executed from within the safety of the context of a
|
||||
Tcl interpreter. In addition to the limited command set of safe
|
||||
Tcl, only a few commands are available to access the database via
|
||||
SPI and to raise messages via <function>elog()</>. PL/Tcl
|
||||
provides no way to access internals of the database server or to
|
||||
gain OS-level access under the permissions of the
|
||||
<productname>PostgreSQL</productname> server process, as a C
|
||||
function can do. Thus, unprivileged database users may be trusted
|
||||
to use this language; it does not give them unlimited authority.
|
||||
</para>
|
||||
<para>
|
||||
The other, implementation restriction is that Tcl functions cannot
|
||||
be used to create input/output functions for new data types.
|
||||
The other notable implementation restriction is that Tcl functions
|
||||
may not be used to create input/output functions for new data
|
||||
types.
|
||||
</para>
|
||||
<para>
|
||||
Sometimes it is desirable to write Tcl functions that are not restricted
|
||||
@ -57,12 +62,12 @@ $PostgreSQL: pgsql/doc/src/sgml/pltcl.sgml,v 2.38 2005/05/20 01:52:25 neilc Exp
|
||||
a user logged in as the database administrator.
|
||||
</para>
|
||||
<para>
|
||||
The shared object for the <application>PL/Tcl</> and <application>PL/TclU</> call handlers is
|
||||
automatically built and installed in the
|
||||
<productname>PostgreSQL</productname>
|
||||
library directory if Tcl support is specified
|
||||
in the configuration step of the installation procedure. To install
|
||||
<application>PL/Tcl</> and/or <application>PL/TclU</> in a particular database, use the
|
||||
The shared object code for the <application>PL/Tcl</> and
|
||||
<application>PL/TclU</> call handlers is automatically built and
|
||||
installed in the <productname>PostgreSQL</productname> library
|
||||
directory if Tcl support is specified in the configuration step of
|
||||
the installation procedure. To install <application>PL/Tcl</>
|
||||
and/or <application>PL/TclU</> in a particular database, use the
|
||||
<command>createlang</command> program, for example
|
||||
<literal>createlang pltcl <replaceable>dbname</></literal> or
|
||||
<literal>createlang pltclu <replaceable>dbname</></literal>.
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user