JDBC connection pooling is the recommended method to connect to your external database. As part of installing the core platform, a JDBC connection pool is usually configured in the configuration file of the application server. Refer to the appropriate Pega Platform Installation Guide for your application server type to determine the correct method of updating the configuration.
See below for an example of the syntax on Tomcat. The data source in the example is set to mktDataSource.
<Resource name="jdbc/mktDataSource" auth="Container" type="javax.sql.DataSource" driverClassName="oracle.jdbc.OracleDriver" url="jdbc:oracle:thin:@<hostname>:1521:prpc" username="<usename>" password="<password>" />