Which type of controller is best suited when you want all of the basic DML functions from an object's normal new/edit page and want to include multiple records?
A Visualforce page contains an industry select list and displays a table of Accounts that have a matching value in their Industry field.
When a user changes the value in the industry select list, the table of Accounts should be automatically updated to show the Accounts associated with the selected industry.
A company has a custom object, Order__c, that has a required, unique, external ID field called Order_Number__c. Which statement should be used to perform the DML necessary to insert new records and update existing records in a List of Order__c records?