Online Transaction Processing (OLTP) systems are characterized by high throughput, many users, and a mix of DML operations (insert, update, and delete) and queries. Most of the information on the Administration page also applies here.
These books contain the most commonly used information for general database administration and development:
Enterprise Manager lets you administer and monitor the database through a browser-based user interface. You can work with one or many database instances, and manage the whole software stack through the Grid Control.
Oracle Database 10g includes many automated performance features, which you access through Oracle Enterprise Manager. You can also learn about and use detailed performance features, such as indexes, hints, and performance-related views in the data dictionary: