QXO supports two modes of operation for a source application: Data Extraction and Direct Data Publish (DDP).

In Data Extraction mode QXO is responsible for extracting business object data after a business event has occurred; the extraction process is orchestrated by the event service. Data Extraction is the most widely used operating mode and works with any Open Edge database. However, this approach has limitations; for example, the fact that data is published after the business event occurs means that the business object data could change during the time between when the event occurred and when the data was extracted.

In Direct Data Publish (DDP) mode, the source application is responsible for getting business object data related to a business event to QXO for processing—QXO does not extract the data. The source application must identify a business event, package the relevant business object data, then pass it to QXO using the DDP API provided by QXO. The DDP API can be called by connecting to a OpenEdge AppServer or by calling the QXI Web service to access the API. The content of the business object published is controlled completely by the source application and can be the result of complex business logic. DDP provides a unique mechanism for collating data to be published to external applications; Data Extraction mode cannot provide this same mechanism since the data is limited to data in the database.

Since QXO is not responsible for extracting data from the source application, the event service is not required for source applications that use DDP. Currently a source application cannot use both Data Extraction and DDP modes. When configuring a DDP source application, you do not have to configure a set of databases, since QXO does not need to connect to the source application database to poll for events and extract data.

With Data Extraction source applications, the business object is user-defined. However, with DDP the business object is defined by the source application: the business object is imported into QXO (rather than being user-defined) and its structure cannot be changed. You create business objects for a DDP source application by importing an XML schema that defines the business object.

Once the data is published, a business object instance is created and the Publish and Deliver phases of the QXO process are executed, using the same rules regardless of the operating mode of the source application. If changes to the data content are required for the subscriber, these changes must be made in the profile definitions for the business object.