The primary target technology for the database is Postgres.The fhirbase, itself installed on a Postgres database and making use of JSONB feature to implement the expected entity extensibility mechanism is implemented using the JSONB feature of Postgres.
Other database support:
SQL-Server
...
Early version of openIMIS supports will thus remain on SQL-Server.
(To be validated) The extensibility mechanism makes use of SQL-Server JSON feature.
Other
Support of other databases must be studied on case-pre-case basis. The use of an ORM framework (Django) is of great help in this area.
However, being database vendor-agnostic is not an easy task and requires many precautions, but phase 2 of the Transformation methodology is dedicated to switch to Postgres.
Other
FHIR implementation (fhirbase) only supports Postgres as database platform. No other database engine (Oracle, DB2, MongoDB,...) will be supported.