Instead of configuring the multiple datasource configuration in seperate -ds.xml files we can configure it in a single datasource configuration file, it can simply be done by adding the additional datasource types in the exsiting -ds.xml file.

Check the sample simple configuration, this configuration will create the local-tx-datasource datasource for mysql+oracle DB

<?xml version="1.0" encoding="UTF-8"?>

 
<datasources>

    <!-- Defining local-tx-datasource -->

    <local-tx-datasource>

        <jndi-name>common-mysqlds</jndi-name>

        <use-java-context>true</use-java-context>

        <connection-url>jdbc:mysql://localhost:3306/testDB</connection-url>

        <driver-class>com.mysql.jdbc.Driver</driver-class>

       <prefill>true</prefill>

        <valid-connection-checker-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLValidConnectionChecker</valid-connection-checker-class-name>

        <check-valid-connection-sql>SELECT @@VERSION</check-valid-connection-sql>

        <exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLExceptionSorter</exception-sorter-class-name>

        <metadata>

          <type-mapping>mySQL</type-mapping>

        </metadata>

    </local-tx-datasource>


    <local-tx-datasource>
        <jndi-name>common-oracleds</jndi-name>
        <connection-url>jdbc:oracle:thin:@localhost:1521</connection-url>
        <driver-class>oracle.jdbc.driver.OracleDriver</driver-class>
        <user-name>scott</user-name>
        <password>tiger</password>
        <prefill>true</prefill>
       <min-pool-size>5</min-pool-size>
       <max-pool-size>6</max-pool-size>
    </local-tx-datasource>
 
</datasources>

Advantages of this pattern

• Single configuration file

Disadvantages of this pattern

• It could lead to http://www.jboss.org/community/wiki/ManagedConnectionisNull