Chapter 10: Updating Relational Data Sources

Overview

In the previous two chapters, we explored how to use the major objects within the .NET Framework for relational data access. This includes the DataReader , Connection , Command , DataAdapter , DataTable , and DataSet objects. We also explored the use of subsidiary objects such as the DataRelation , DataRow , Parameter , and others. You've seen how to use these objects in a range of combinations to extract data from a relational data store and work with that data.

The techniques demonstrated included examination of the ways you can update the data that is held within the confines of the disconnected DataSet objects that you created. What you haven't looked at is how you can perform that final step required in any application used fundamentally for updating a data store “how to push your changes back into the data store.

Even in a connected environment, such as a traditional client-server application, the process of managing updates to the source data is not without its own problems, in particular the managing of concurrent updates to the source data. While .NET does not introduce any new problems, the concept of working with data in a fundamentally disconnected way (such as .NET provides) means that you need to be fully aware of the issues and know how to handle them. This is the core topic of this chapter. You will look at:

• Updating data sources with a Command object.

• Using transactions when updating data sources.

• Updating data sources from a DataSet object.

• A detailed look inside the DataAdapter Update method.

• Managing concurrent updates to a data source.