FATAL: database does not exist in postgresql for jdbc I create a database by installing Postgres on my ubuntu 20.04 machine and used the following commands to create it:
sudo su - postgres
psql
CREATE USER preopus WITH PASSWORD 'admin222';
CREATE DATABASE preopusDB WITH OWNER=preopus;

and received no errors. When I tried using slick-codegen by calling the database with this URL:
&quot;jdbc:postgresql://localhost/preopusDB?user=preopus&amp;password=admin222&quot;, it gave me the error:

[error] (run-main-0) org.postgresql.util.PSQLException: FATAL: database &quot;preopusDB&quot; does not exist

If anybody can help it would be greatly appreciated.
As a_horse_with_no_name mentioned, the database name (and possibly other parameter values) in the JDBC URL are case-sensitive. But any unquoted identifier like preopusDB in your CREATE DATABASE statement will be folded to lower case.
Use
jdbc:postgresql://localhost/preopusdb?user=...