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>