How do you close a database connection?

What is the correct order to close database connection?

The rules for closing JDBC resources are: The ResultSet object is closed first, then the Statement object, then the Connection object.

Do I need to close database connection?

If you do not close your database connections, many problems can occur like web pages hanging, slow page loads, and more.

What happens if you don't close a database connection?

If you don't close it, it leaks, and ties up server resources. @EJP The connection itself might be thread-safe (required by JDBC), but the applications use of the connection is probably not threadsafe. Think of things like different transaction isolation, boundaries (commit/rollback/autocommit) etc.

How do I close all existing connections on a database in SQL Server?

In more recent versions of SQL Server Management studio, you can now right click on a database and 'Take Database Offline'. This gives you the option to Drop All Active Connections to the database.