Can not load default MySQL library (libmysqlclient.so.18 or libmysqlclient.so)

Hi fellows I have a problem after changing from mysql to mariadb. This has happend.

1. A few years ago a wrote a project in Lazarus and mysql 5.5.
2. This summer a lightning destroyed my raspberry pi 2 B:
3. . I purshased a new, installed Lazarus, installed database witch this time was mariadb 10.3. I also chaged connection object to MySQL56Connection from previously MySQL55, acording to information I found on the net, and then downloaded my source code.
4. . Project compiled OK, but when the program started I got error in Header , ” Can not load default MySQL library (libmysqlclient.so.18 or libmysqlclient.so)”
5. . I have reinstalled everything several times but got same result every time.

I dont know what to do! I have not found the missing files for download. I have been told that I should not need to onstall .so files on my one.

Install mysql from oracle, i reely don’t care which of the db I use as long as they work, but Mysql seems tricky to install nowadays.
Install Sybase! Also not mainstreem,
Use plain files and write my one routines to find and select the information I need. This will take me some time, but will sertainly work.

But my first choice will be to use mariadb as this is default for raspberry. Does anyone know how to solv my problem.
Thanks in advance.
Best rgds
Lennart from Sweden