We've commented on this upcoming functionality before, as information has become available at past Lotuspheres. Have a look at our Sphere 2004 report at http://www.dominopower.com/issues/issue200402/00001217001.html and for 2003 at http://www.dominopower.com/issues/issue200302/lotusphere001.html.

The power of storing Notes databases in DB2 comes not just from the performance improvements that will be available for applications that need it, but more from the ability to see the Notes data in some kind of relational form and work with it from there, while still maintaining the Notes access controls against the data.

Just don't get too carried away about your Notes data magically being relational, though! Firstly, the DB2 option is only available on servers. Local databases on clients are still stored as .NSF files. The server's NSF layer maps the data to DB2. The storage in DB2 is that of the Notes data model, it's not suddenly made the data all fully relational. While you can read -- and write -- the data with SQL from non-Notes applications, you will still be dealing with the Notes data model.

So how does Notes data storage compare to a relational database? Why isn't Notes already a relational database?

The Notes database
The fundamental reason why Notes isn't a relational database is because it isn't. The organization of a Notes database is different from that of a relational database, which contains tables of same-type "records," or sets of fields, and is optimized for rapid access by table-oriented operations.

A Notes database can contain any number of notes, and a note can contain any number and type of fields. In addition, there is information in the database header and in each note header that supports simultaneous access and replication between databases.

This schema-less database architecture means that Notes is uniquely able to store highly disparate data types in the one database extremely efficiently, given what Notes is expected to do. It does tend to occupy more disk space, because the data elements also carry their meta-data with them, but it is efficient in terms of space management, and of course the architecture is optimized for Notes' replication capabilities, which is one of Notes unique features.