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<?xml version="1.0" encoding="ISO-8859-1"?>
<!--
-
- This file is part of the OpenLink Software Virtuoso Open-Source (VOS)
- project.
-
- Copyright (C) 1998-2018 OpenLink Software
-
- This project is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by the
- Free Software Foundation; only version 2 of the License, dated June 1991.
-
- This program is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
-
- You should have received a copy of the GNU General Public License along
- with this program; if not, write to the Free Software Foundation, Inc.,
- 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
-
-
-->
<sect1 id="createexthostproc"><title>CREATE PROCEDURE Syntax - External hosted procedures</title>
<para>Virtuoso provides a syntax shortcut for calling static method from hosted user defined types without first defining a Virtuoso external hosted user defined type:</para>
<programlisting><![CDATA[
CREATE (PROCEDURE|FUNCTION) <local_name> ([<arg_def1>, ...])
[returns <sql_datatype>] LANGUAGE [JAVA|CLR] EXTERNAL NAME '<external_static_proc_name_literal>'
<arg_def> := [IN|OUT|INOUT] param_name <data_type_spec>
<external_static_proc_name_literal> = <external_type_name_literal>.<static_proc_name>]]></programlisting>
<para>This compiles into an functional equivalent of :</para>
<programlisting><![CDATA[
create procedure <local_name) ([<arg_def1>, ....])
{
declare ret any;
exec ('
create type <local_name>
temporary self as ref
static method m1 ([<arg_def1>, ....])
returns <datatype> EXTERNAL NAME ''<static_proc_name>''
');
ret := <local_name>::m1 (....);
exec ('drop type <local_name>');
return ret;
}
]]></programlisting>
<para>For more details see <link linkend="udtcreatetypestmt">CREATE TYPE</link> and <link linkend="runtimehosting">Runtime hosting</link> chapters.</para>
<example id="ex_createexthostproc_jvm"><title>CREATE PROCEDURE for a Java method:</title>
<para>Here is an example for CREATE PROCEDURE and the hosted Java VM:</para>
<programlisting><![CDATA[
create procedure get_property (in x varchar) returns varchar language java external name 'java.lang.System.getProperty';]]></programlisting>
<para>Here's how that procedure is called:</para>
<programlisting><![CDATA[
SQL> select get_property ('java.vm.name');
callret
VARCHAR
_______________________________________________________________________________
Java HotSpot(TM) Client VM
]]></programlisting>
</example>
<example id="ex_createexthostproc_clr"><title>CREATE PROCEDURE for a CLR method:</title>
<para>Here is an example for CREATE PROCEDURE and the hosted CLR:</para>
<programlisting><![CDATA[
create procedure curr_thr_id () returns integer language CLR external name 'mscorlib/System.AppDomain.GetCurrentThreadId';]]></programlisting>
<para>Here's how that procedure is called:</para>
<programlisting><![CDATA[
SQL> select curr_thr_id();
callret
INTEGER
_______________________________________________________________________________
2156
]]></programlisting>
</example>
</sect1>
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