NavDB is a database with key-value and (experimental) relational models.
The project website was abandoned in 2019 and the Github repository was removed.
Relational Key/Value
Custom API SQL Command-line / Shell
Disk-oriented In-Memory Hybrid
N-ary Storage Model (Row/Record)
https://navdb.io/
https://github.com/Navigator-Data
https://navdb.io/docs/
Navigator Data
ZA
2017
2019
Commercial
C++
C, C++, Java, PHP, Python
Linux, OS X, Windows
Apache v2, Proprietary