LDAP and RDBMs have often been opposed in the past with LDAP being the preferred service for fast frequent lookups, authentication and authorization, and RDBMs being the preferred service to write large data, updated frequently, mined some time to time.
But both technologies have some things in common: they are data stores and they are heavily used. And often, within an enterprise or a service provider, the data stored in the RDBMs is duplicated from the LDAP directory service (or vice-versa).
So there is an interest in sharing the data between RDBMs and LDAP. There are different ways to achieve this.
At the MySQL conference on April 20-23, 2009, we will be holding a BoF session to discuss how to make use of LDAP with MySQL databases, with Sun products : Sun Directory Server Enterprise Edition and OpenDS.
I hope to see you there.