RAD Studio VCL Reference
|
TDataSetProvider provides data from a dataset and resolves updates to that dataset or its database server.
TDataSetProvider = class(TBaseProvider);
class TDataSetProvider : public TBaseProvider;
Provider
Use TDataSetProvider to provide data from a dataset to a client dataset or XML broker and to resolve updates from that client dataset or XML broker back to the dataset or to its underlying database server. TDataSetProvider can be a part of the same application as the client dataset or XML broker, or it can be placed in the application server of a multi-tiered application. It serves as a data broker between a remote database server and a client dataset.
TDataSetProvider packages data from a dataset and passes it in one or more transportable data packets to the client dataset or XML broker. The client dataset reconstructs the data in the data packet to create a local, in-memory copy for user access. When user access is complete, the client dataset repackages any changed data and sends the updates back to the provider. The provider applies the updates to the database or source dataset.
When the provider supplies data to a client dataset, the client dataset reconstructs the data in the data packet to create a local, in-memory copy for user access. When user access is complete, the client dataset repackages any changed data and sends the updates back to the provider. The provider applies the updates to the database or source dataset.
When the provider supplies data to an XML broker, the XML broker adds the data packet, in XML format, to an HTML document that is downloaded by a Web client. When the XML broker receives updates from the Web client, it sends the updates to the provider, which applies them to the database or source dataset.
Client datasets and XML brokers communicate with a provider through the IAppServer interface. In multi-tiered applications, this is the interface of the remote data module that contains the provider. To enable the remote data module to pass calls to the provider, the provider's Exported property must be true, and its Owner property must specify the remote data module.
Copyright(C) 2008 CodeGear(TM). All Rights Reserved.
|
What do you think about this topic? Send feedback!
|