Frickler

Interbase has virtually no internal functions. Not even in the newest versions. All has to be done in UDFs. The Firebird developers on the other hand had changed that from the beginning.

Full support including the new 128 Bit types, timestamp with timezone and the new batch API for INSERT/UPDATE? I ask because UniDAC/IBDAC only supports a subset at this time.

Using SQL, it's slow. But Absolute Database isn't made for SQL, but for good ol' ISAM: IndexName, SetRange, Locate, Filter, you name it. There (and in single user mode) it is really fast. And you not only don't need any DLLs to access it, you can even embed the database into the EXE (for read only databases such as catalogues).

But interposers did.

It's possible that Interbase supports only "simple case", that is case foo when 1 then 'one' when 2 then 'two' else 'many' end

What if you remove the parentheses around the case statement?

Is it possible to do manipulations like "multiply all 'Left' properties by 2" using this DFM Editor?

Pascal example: https://github.com/Arcantar/FirebirdSQL_Sample

Could you please provide the source code of your little demo?