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Pass the Data
Consider multiple options for passing data.
by Jackie Goldstein

VSLive! San Francisco, March 25, 2004

Note: Jackie Goldstein is presenting "Strategies for Passing and Caching Data" at VSLive! San Francisco on Friday, March 26. These tips are from that session.

Multiple Options
You can consider many different approaches for implementing the interface between the data access layer and the rest of an application that uses that data. Various ways to pass this data include:

• Passing scalar values
• Passing XML
• Passing DataSets
• Passing business-entity components
• Returning data readers

Each of these alternatives has its pluses and minuses. For example, the .NET Framework DataSet has the advantages of native (built-in) functionality, support for collections of business entities, built-in support for serialization, and easy maintenance. However, it also has the disadvantages of performance issues due to the overhead of instantiating and marshalling the data in DataSets, as well as the disadvantage of not being intended or designed to represent a single instance of a business entity. Similarly, all other options have their advantages and disadvantages. The bottom line is that you need to understand the available options along with their advantages and disadvantages to make the correct design choice for every project and/or application design point.

ObjectSpaces
There's a new technology in ADO.NET Whidbey called ObjectSpaces, which allows for the definition and use of business objects throughout an application. With ObjectSpaces, these business objects are completely decoupled from their actual data source (such as SQL Server). All manipulations and searches are done on the objects themselves. At some point, of course, data must actually be read from the data sources; then updates to the data must eventually be written back to the actual data source. The ObjectSpaces objects can perform these data source reads and writes automatically based on an externally specified object-relational mapping. You should seriously consider using ObjectSpaces in Whidbey if your approach to passing and caching data is heavily focused on business objects.

About the Author
Jackie Goldstein is the principal of Renaissance Computer Systems. He has almost 20 years experience developing and managing software applications in the United States and Israel, and is experienced at helping companies understand and utilize new technologies. Jackie is the MSDN regional director for Israel and the founder of the Israel VB User Group.