How to build a database that adds additional code based on lgtm's database

Hello! Sorry to take up your time, I have a problem to discuss the appropriate solution.

I downloaded a project [database](https://lgtm.com/projects/g/apache/logging-log4j2/ci/#ql) from lgtm for security research.I want to use this project as a dependency to write some additional test code, and then create a new database with the additional test code and the project source code.

I have only one solution at present：Merge test code and project code，Then execute the command
`codeql database create log4j2-custom -l java --overwrite`

This can be created successfully after multiple compilation failures with maven. But this is a complete recreation of a database, without using the compiled database on lgtm. Is there any easier way to add new code to an existing database without recompiling the whole project?