Dataman is a fully multi-threaded database server and client API libraries in C, C++, Java, and a PHP module has now been added as well. This is a 'direct access' database, not a relational one. It emulates the verbs of the EDITOR language.
MoneyTrack is a personal financial recording system, means it keeps track of your incomes / expenses via a database which can be accessed in different ways. There are several frontends available (web frontend, java-client, ...).
lib4d_sql is a C library providing the required functions (connect, prepare, execute, ...) to write a SQL client for 4D databases. It uses the public 4D SQL protocol wich is supported by 4D products since... the version 11. It is already used by the PDO_