Create a connection to another database

To create a new connection add a new connection code to app/etc/local.xml after primary database section.

Check the following example of local.xml:

<?xml version="1.0"?>
<config>
    <global>
        <install>
            <date><![CDATA[]]></date>
        </install>
        <crypt>
            <key><![CDATA[]]></key>
        </crypt>
        <disable_local_modules>false</disable_local_modules>
        <resources>
            <db>
                <table_prefix><![CDATA[]]></table_prefix>
            </db>
            <default_setup>
                <connection>
                    <host><![CDATA[host]]></host>
                    <username><![CDATA[username]]></username>
                    <password><![CDATA[password]]></password>
                    <dbname><![CDATA[dbname]]></dbname>
                    <initStatements><![CDATA[SET NAMES utf8]]></initStatements>
                    <model><![CDATA[mysql4]]></model>
                    <type><![CDATA[pdo_mysql]]></type>
                    <pdoType><![CDATA[]]></pdoType>
                    <active>1</active>
                </connection>
            </default_setup>
            <!-- START new connection to wordpress database !-->
            <wordpress_setup>
                <connection>
                    <host><![CDATA[wordpress_host]]></host>
                    <username><![CDATA[wordpress_database_username]]></username>
                    <password><![CDATA[wordpress_database_password]]></password>
                    <dbname><![CDATA[wordpress_database_name]]></dbname>
                    <initStatements><![CDATA[SET NAMES utf8]]></initStatements>
                    <model><![CDATA[mysql4]]></model>
                    <type><![CDATA[pdo_mysql]]></type>
                    <pdoType><![CDATA[]]></pdoType>
                    <active>1</active>
                    <use>0</use>
                </connection>
            </wordpress_setup>
            <!-- FINISH new connection to wordpress database !-->
        </resources>
        <session_save><![CDATA[files]]></session_save>
    </global>
    <admin>
        <routers>
            <adminhtml>
                <args>
                    <frontName><![CDATA[admin]]></frontName>
                </args>
            </adminhtml>
        </routers>
    </admin>
</config>

After changing the local.xml file, you must clear the magento cache.