Does In Memory Data Base exist as a library?

Question

Database

Hello!
People tell me if there are local versions of In Memory Data Base in the form of libraries so that nothing extra needs to be delivered on the client side, ideally a cross-platform solution. Of course, there is an option to put SQLight into the RAM, but IMHO it was not done for this.
Task: process a large amount of data on the client in real time.
UPD: the data in the database practically does not change, mostly it is only added. But a situation may arise when part of the data needs to be updated (for example, in the case of incorrectly received data). One process adds data to the database, others are already making data selections by key or keys (full-text keys were originally planned, but I think it makes sense to replace them with digital ones and make an intermediate correspondence plate) and process this data, returning the result.

Answer 1

sqlite?