I cannot make out what is happening in the database field. The open source projects have yielded robust RDBMS tools that provide all the basic functionality needed by most applications.
The mainstream commercial RDBMS vendors are beginning to offer "free" versions of their flagship products. These versions have limitations but are more complete than previous "lite" versions.
Sun recently announced that they will integrate a version of PostgreSQL into of Solaris. This is significant given that SUN is the first platform Oracle has shipped on for years and SUN owes most of it's "large iron" sales to Oracle database installations.
Oracle has been more focused on expanding their application offerings by acquiring other application vendors. The database engine itself has not seen any significant improvements since Oracle 8.
Microsoft, as far back as 2001, has made announcements of it's plans to replace Windows File System with a version of the SQL Server database engine. But this must have proved harder than expected as it is still not available.
Google's Base may point the way to the concept of database technology as a service. In this case free, ad-supported database functionality without the hassles of deployment hardware, installation, or maintenance.
Is the RDBMS as we know it getting assimilated?
Open source RDBMS include:
Available so-called "Free" RDBMS are: