<para>
This form of the <literal>AS</literal> clause is used for
dynamically loadable C language procedures when the procedure name
in the C language source code is not the same as the name of
the SQL procedure. The string <replaceable
class="parameter">obj_file</replaceable> is the name of the shared
library file containing the compiled C procedure, and is interpreted
as for the <link linkend="sql-load"><command>LOAD</command></link> command. The string
<replaceable class="parameter">link_symbol</replaceable> is the
procedure's link symbol, that is, the name of the procedure in the C
language source code. If the link symbol is omitted, it is assumed
to be the same as the name of the SQL procedure being defined.
</para>
<para>
When repeated <command>CREATE PROCEDURE</command> calls refer to
the same object file, the file is only loaded once per session.
To unload and
reload the file (perhaps during development), start a new session.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">sql_body</replaceable></term>
<listitem>
<para>
The body of a <literal>LANGUAGE SQL</literal> procedure. This should
be a block
<programlisting>
BEGIN ATOMIC
<replaceable>statement</replaceable>;
<replaceable>statement</replaceable>;
...
<replaceable>statement</replaceable>;
END
</programlisting>
</para>
<para>
This is similar to writing the text of the procedure body as a string
constant (see <replaceable>definition</replaceable> above), but there
are some differences: This form only works for <literal>LANGUAGE
SQL</literal>, the string constant form works for all languages. This
form is parsed at procedure definition time, the string constant form is
parsed at execution time; therefore this form cannot support
polymorphic argument types and other