postgresql/doc/src/sgml/ref/drop_language.sgml
Peter Eisentraut 9081bddbd7 Improve <xref> vs. <command> formatting in the documentation
SQL commands are generally marked up as <command>, except when a link
to a reference page is used using <xref>.  But the latter doesn't
create monospace markup, so this looks strange especially when a
paragraph contains a mix of links and non-links.

We considered putting <command> in the <refentrytitle> on the target
side, but that creates some formatting side effects elsewhere.
Generally, it seems safer to solve this on the link source side.

We can't put the <xref> inside the <command>; the DTD doesn't allow
this.  DocBook 5 would allow the <command> to have the linkend
attribute itself, but we are not there yet.

So to solve this for now, convert the <xref>s to <link> plus
<command>.  This gives the correct look and also gives some more
flexibility what we can put into the link text (e.g., subcommands or
other clauses).  In the future, these could then be converted to
DocBook 5 style.

I haven't converted absolutely all xrefs to SQL command reference
pages, only those where we care about the appearance of the link text
or where it was otherwise appropriate to make the appearance match a
bit better.  Also in some cases, the links where repetitive, so in
those cases the links where just removed and replaced by a plain
<command>.  In cases where we just want the link and don't
specifically care about the generated link text (typically phrased
"for further information see <xref ...>") the xref is kept.

Reported-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Discussion: https://www.postgresql.org/message-id/flat/87o8pco34z.fsf@wibble.ilmari.org
2020-10-03 16:40:02 +02:00

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<!--
doc/src/sgml/ref/drop_language.sgml
PostgreSQL documentation
-->
<refentry id="sql-droplanguage">
<indexterm zone="sql-droplanguage">
<primary>DROP LANGUAGE</primary>
</indexterm>
<refmeta>
<refentrytitle>DROP LANGUAGE</refentrytitle>
<manvolnum>7</manvolnum>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
<refnamediv>
<refname>DROP LANGUAGE</refname>
<refpurpose>remove a procedural language</refpurpose>
</refnamediv>
<refsynopsisdiv>
<synopsis>
DROP [ PROCEDURAL ] LANGUAGE [ IF EXISTS ] <replaceable class="parameter">name</replaceable> [ CASCADE | RESTRICT ]
</synopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
<command>DROP LANGUAGE</command> removes the definition of a
previously registered procedural language. You must be a superuser
or the owner of the language to use <command>DROP LANGUAGE</command>.
</para>
<note>
<para>
As of <productname>PostgreSQL</productname> 9.1, most procedural
languages have been made into <quote>extensions</quote>, and should
therefore be removed with <link linkend="sql-dropextension"><command>DROP EXTENSION</command></link>
not <command>DROP LANGUAGE</command>.
</para>
</note>
</refsect1>
<refsect1>
<title>Parameters</title>
<variablelist>
<varlistentry>
<term><literal>IF EXISTS</literal></term>
<listitem>
<para>
Do not throw an error if the language does not exist. A notice is issued
in this case.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">name</replaceable></term>
<listitem>
<para>
The name of an existing procedural language.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>CASCADE</literal></term>
<listitem>
<para>
Automatically drop objects that depend on the language (such as
functions in the language),
and in turn all objects that depend on those objects
(see <xref linkend="ddl-depend"/>).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>RESTRICT</literal></term>
<listitem>
<para>
Refuse to drop the language if any objects depend on it. This
is the default.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Examples</title>
<para>
This command removes the procedural language
<literal>plsample</literal>:
<programlisting>
DROP LANGUAGE plsample;
</programlisting></para>
</refsect1>
<refsect1>
<title>Compatibility</title>
<para>
There is no <command>DROP LANGUAGE</command> statement in the SQL
standard.
</para>
</refsect1>
<refsect1>
<title>See Also</title>
<simplelist type="inline">
<member><xref linkend="sql-alterlanguage"/></member>
<member><xref linkend="sql-createlanguage"/></member>
</simplelist>
</refsect1>
</refentry>