ZDBase: Portable Database Engine
ZDBase is a relatively simple database storage engine. It's more of an alternative to Berkeley DB (as it was) than a replacement for MySQL. It supports an arbitrary number of tables, records and typed/named fields within those records. Each table maintains as many indices as desired, and the schema can be updated at any time. All data is kept in a blockstore, so everything lives in a single file, and the code and data are portable across platforms.
This was my first serious use of B-Trees, the essential basis of most high-performance disk-based storage systems. The searching of B-Tree content and the insertion of new data is well documented in numerous sources, but the deletion of data is invariably left as an exercise for the reader, which was a bit frustrating but ultimately empowering.
