how to update a database using a dataset

The dataset was probably populated by a dataadapter, using its select command property. The dataadapter has a handle to the dataset. It should also have an update command, insert command and delete command properties. Each property has a command to update the database with the changes to the dataset. This is not something I've done for a while, but I think to make the datasource apply these changes to the database you execute its applyupdates method.