The JDBC database connection URL for a database depends on the type of database you are connecting to. Here are some common databases and their JDBC connection URLs:

1. MySQL

jdbc:mysql://hostname:port/databasename

Replace "hostname" and "port" with the host and port where MySQL is running, and "databasename" with the name of the database you want to connect to.

2. Oracle

jdbc:oracle:thin:@hostname:port:databasename

Replace "hostname" and "port" with the host and port where Oracle is running, and "databasename" with the name of the database you want to connect to.

3. SQL Server

jdbc:sqlserver://hostname:port;databaseName=databasename

Replace "hostname" and "port" with the host and port where SQL Server is running, and "databasename" with the name of the database you want to connect to.

4. PostgreSQL

jdbc:postgresql://hostname:port/databasename

Replace "hostname" and "port" with the host and port where PostgreSQL is running, and "databasename" with the name of the database you want to connect to.

5. SQLite

jdbc:sqlite:path/to/database/file

Replace "path/to/database/file" with the path to the SQLite database file.

These are just a few examples of common databases and their JDBC connection URLs. The exact format of the URL may vary depending on the database and the specific configuration.