Open-Source C or C++ Embedded relational database (copy source to deploy)

Question

I have a cross platform project where the client gets the code, but doesn't want to resolve any dependencies. The requirements are best solved with a relational database, so it seems I need to copy the source of an embeddable relational database into my program and compile the library directly into the executable or as part of the project.

Is there a relational embeddable database which has a permissive license so that I can copy the source directly into the project? Which one has the smallest code base? Ideally I'm thinking of one C source file and one header that I can copy into the program and start using immediately.

Answer 1

SQLite

They have “amalgamation” source distribution which is one C source file, which can be included into a project and used right away.

Answer 2

SQLite comes to mind.