Relational database: An ongoing debate

Ten years ago I wrote: 'Using a directory for relational data or a relational DBMS for directory data is like using a hammer to cut wood: It can be done, but a real carpenter wouldn't do it.'

Over the years I've been writing about identity services it's always been taken as a given that the data store for identity information is a directory system (such as eDirectory, Active Directory, iPlanet, etc.). But there have always been those who espoused a relational database (RDBMS) as a "better" data store. It's an argument that's been going on for the entire 10 years this newsletter has been published, and one that is more political in nature than technological.

Over the years I've been writing about identity services it's always been taken as a given that the data store for identity information is a directory system (such as eDirectory, Active Directory, iPlanet, etc.). But there have always been those who espoused a relational database (RDBMS) as a "better" data store. It's an argument that's been going on for the entire 10 years this newsletter has been published, and one that is more political in nature than technological.

In June, 2000, for example, I wrote: "Every special-purpose database is designed and structured to perform its special purpose optimally. A relational DBMS is designed to let items of data be related to one another either permanently or on an ad hoc basis, while a directory service uses the object-oriented style of database (with its built-in hierarchy) to create a database supporting a tree-like view of the data." That's still true today, of course -- choose the best data structure for the work you want to do. As I concluded: "Using a directory for relational data or a relational DBMS for directory data is like using a hammer to cut wood: It can be done, but a real carpenter wouldn't do it."

What's interesting about the discussion from 10 years ago is a follow-up edition I wrote ("More information on object-oriented databases"). Interesting, because a new argument is raging today -- whether relational databases should be replaced by XML structures with the reason given that the XML structures are more flexible. Interesting, because of a pointer I provided to an authority on "object-oriented" databases (OODB). XML databases are merely an outgrowth of OODBs. Check the work here   and see how today's "hot topic" really shows how there's rarely something new in the world.

The object-oriented, hierarchical directory service is still the best place to store identity data. Can that be "XML-ized"? Sure, it doesn't change the nature of the data store, merely it's representation. If that allows the data to be more easily used by today's applications and services, then that would also encourage coders to use existing identity stores for their apps and services. And that should benefit all of us.

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Database, SQL and RDBMS 
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