Data Sources and Binding

[This is preliminary documentation and subject to change.]

The term data source is intended to be generic, meaning any object or store that can act as a repository of data. Examples of data sources include CDO objects, ADO objects, Web Store items, and Active Directory objects. The term binding refers to the state of two objects being associated, or linked, at runtime. When you use an OLE DB provider to create or modify an item in the Web Store, you first bind the object in the store, and then make changes to its properties or streams. Once the data source is bound, the data within the data source can be modified, deleted, created, and so on.

Once a binding has occurred, there are two copies of data present: the data within the binding object (the binder), and the data source. For example, when you use an ADO Record object to bind to an existing item in the Web Store, the data within the Record object is a copy of the data within the store. Similarly, when you use a CDO Message object to bind to an ADO Record object, the data within the Record object is copied into the Message object. When you make changes to the data within the binding object, these changes are never saved back to the data source automatically; you must commit the changes using an appropriate method call.

ADO and CDO objects both can bind to items in the Web Store using an appropriate OLE DB provider. Thus, both ADO and CDO objects can have Web Store items as data sources. CDO objects, on the other hand, can have other objects as data sources. For example, a CDO Message object can bind to an ADO Record object, an ADO Stream object, a CDO BodyPart object, or any object exposing an implementation of the IStream interface.