To extend a little bit on kyle's example the first part of a DBI->connect() is referred to as the dsn or the Data Source Name. The DSN generally is used to store values that are needed to connect to a database. The DSN generally follows the same format for determining which driver to use and what database to connect too. After that any additional parameters will generally be database specific (like user and password).

For example mysql has a specific parameter mysql_connect_timeout. For DB2 there is db2_query_timeout.

In your case, the example that you copied looks like to be using parameters from an older version of DBD::mysql. The sample kyle submitted should work. If you have questions you should start looking in the DBI documentation and then move to the driver specific documentation.