Question

I have web project in which I am using OpenJAP for database connectivity. I have configured the persistence.xml and I am able to connect to the database and retrieve the data. But in the console output I am seeing this entry

1953  OpenJPA  TRACE  [main] openjpa.jdbc.SQL - <t 31156635, conn 6888942> executing prepstmnt 9690924 

UPDATE student 
    SET scourse = ?, sname = ?, sroll = ? 
    WHERE id = ? 
[params=?, ?, ?, ?]

In my whole project till now I have not added any prepared statement or any update statement. I want to know why is OpenJPA executing this statement and what would be performance implication when I am fetching big data in the range of millions?

Answer 1

I have added following code to my build.xml file

<!-- ***************************************************************************************************************** -->
<!-- DO NOT DELETE FOLLOWING CODE. THIS IS ADDED FOR ENCHANCING THE CLASSES AT COMPILE TIME. IT IS REQUIRED BY OPENJPA -->
<!-- Define the classpath to include the necessary files. -->
<!-- ex. openjpa jars, persistence.xml, orm.xml, and target classes  -->
<path id="jpa.enhancement.classpath">
    <!-- Assuming persistence.xml/orm.xml are in WebContent/WEB-INF/classes/META-INF -->
    <pathelement location="WebContent/WEB-INF/classes" />

    <!-- Location of the .class files -->
    <pathelement location="build/classes" />

    <!-- Add the openjpa jars -->
    <fileset dir=".">
        <include name="**/lib/*.jar" />
    </fileset>
</path>
<!-- define the openjpac task; this can be done at the top of the -->
<!-- build.xml file, so it will be available for all targets -->
<taskdef name="openjpac" classname="org.apache.openjpa.ant.PCEnhancerTask" classpathref="jpa.enhancement.classpath" />

<!-- invoke enhancer on all .class files below the model directory -->
<openjpac>
    <classpath refid="jpa.enhancement.classpath" />
    <fileset dir=".">
        <include name="**/model/*.class" />
    </fileset>
</openjpac>
<echo message="Enhancement complete" />
<!-- ***************************************************************************************************************** -->

On adding this and setting the eclipse to use this build.xml file to create the WAR file. The objects are getting enhanced and I am not getting the “Executing the prepared statement” Trace in my log also it is not executing the extra “Update” statement.