3:03 a.m.
Author: rareddy
Date: 2011-04-28 14:03:41 -0400 (Thu, 28 Apr 2011)
New Revision: 3129
Modified:
trunk/documentation/developer-guide/src/main/docbook/en-US/content/udf.xml
Log:
TEIID-1569: updating the doc to reflect the development of the udf pushdown functions.
Modified: trunk/documentation/developer-guide/src/main/docbook/en-US/content/udf.xml
===================================================================
--- trunk/documentation/developer-guide/src/main/docbook/en-US/content/udf.xml 2011-04-28
16:15:17 UTC (rev 3128)
+++ trunk/documentation/developer-guide/src/main/docbook/en-US/content/udf.xml 2011-04-28
18:03:41 UTC (rev 3129)
@@ -8,8 +8,8 @@
creating a UDF.</para>
<section id="define_udf">
<title>UDF Definition</title>
- <para>A FunctionDefinition.xmi file provides metadata to the
- query engine on User Defined Functions. See the Designer Documentation for more on
creating a Function Definition Model.</para>
+ <para>A {FunctionDefinition}.xmi file provides metadata to the query engine on
User Defined Functions.
+ See the Designer Documentation for more on creating a Function Definition
Model.</para>
<itemizedlist>
<para>The following are used to define a UDF.</para>
<listitem>
@@ -56,7 +56,8 @@
<emphasis>Pushdown</emphasis>
- can be one of REQUIRED, NEVER, ALLOWED. Indicates the expected
pushdown behavior. If NEVER or ALLOWED are specified then a Java
- implementation of the function should be supplied.
+ implementation of the function should be supplied. If REQUIRED is used, then user
must extend the
+ Translator for the source and add this function to its pushdown
function library.
</para>
</listitem>
<listitem>
@@ -78,6 +79,12 @@
<para>Even pushdown required functions need to be added as a UDF to allow
Teiid to properly parse and resolve the function. Pushdown scalar functions differ
from normal user-defined functions in that no code is provided for evaluation in the
engine.
An exception will be raised if a pushdown required function cannot be evaluated by
the appropriate source.</para>
+
+ <note>
+ <title>Dynamic VDBs</title>
+ <para>Currently there is no provision to add UDF when you are working
with the Dynamic VDBs. However, you can
+ extend the Translator to define source pushdown functions.</para>
+ </note>
</section>
<section>
<title>Source Supported UDF</title>
@@ -115,8 +122,8 @@
<para>
<emphasis>Required</emphasis>
- extend the OracleExecutionFactory and add SCORE and CONTAINS as
- supported functions. For this example, we'll call the class
- MyOracleExecutionFactory. Add the
+ supported pushdown functions by either overriding or adding additional functions in
"getPushDownFunctions" method.
+ For this example, we'll call the class MyOracleExecutionFactory.
Add the
<code>org.teiid.translator.Translator</code>
annotation to the class, e.g.
<code>@Translator(name="myoracle")</code>
@@ -133,7 +140,9 @@
<para>
Create a new translator jar containing your custom
ExecutionFactory. Refer to <xref linkend="translator_package"/> and
- <xref linkend="translator_deploy"/> for instructions on using the
JAR file.
+ <xref linkend="translator_deploy"/> for instructions on using the
JAR file. Once this is extended
+ translator is deployed in the Teiid Server, use "myoracle"
as
+ translator name instead of the "oracle" in your VDB's
Oracle source configuration.
</para>
</listitem>
</itemizedlist>