Metakit for Tcl extension
Metakit is an embeddable database which runs on Unix, Windows, Macintosh, and other platforms. It lets you build applications which store their data efficiently, in a portable way, and which will not need a complex runtime installation. In terms of the data model, Metakit takes the middle ground between RDBMS, OODBMS, and flat-file databases - yet it is quite different from each of them.
WHAT IT ISN'T - Metakit is not: 1) an SQL database, 2) multi-user/-threading, 3) scalable to gigabytes, 4) proprietary software, 5) a toy.
Mk4tcl is Metakit for Tcl extension, which allows you to create, access, and manipulate Metakit datafiles using Tcl.