The default personDirectoryContext.xml includes JDBC beans to retrieve attributes for local uPortal users such as fragment owners. Below is a real example of merging in additional attributes via the PersonDb DataSource. This is essentially the configuration used in production at Yale. Note that this configuration uses the support for mapping a column to multiple uPortal attribute names.
Since we want to merge attributes from our JDBC source with other attributes we start by adding a reference to our new bean (myunivCachingPersonDbJdbcAttributeSource) to the merging DAOs section.
Then we create the new DAO bean with a SingleRowJdbcPersonAttributeDao going against PersonDB. PersonDB can be defined in rdbm.properties or more likely via JNDI. For information on creating JNDI datasources for uPortal see Using JNDI managed DataSources.