Teach yourself Database Programming
with Visual C++ 6 in 21 days

Week 3...
        In Review

In Day 15, to start your final week of study, you learned to view ODBC and DAO API applications and understand the mechanisms used to process databases. You took a look at using the MFC wrapper classes. Also, you saw that data binding is automatically performed and the RFX mechanism is configured.

In Day 16's lesson, you saw how OLE DB builds on and expands the capabilities of ODBC. Because OLE DB providers can be written for nonrelational data sources, OLE DB provides an interface to relational, as well as nonrelational, data sources. OLE DB takes an object-oriented approach to database client development, whereas ODBC takes a function-based API approach. The OLE DB object hierarchy consists of just a few objects, which expose COM interfaces to perform well-defined sets of functions.

You learned on Day 17 the process of integrating OLE DB into applications by examining the relationship between COM and OLE DB and seeing how COM technology influences the OLE DB programming model.

On Day 18, you examined OLE DB objects, specifically the Session and Command objects, and the interfaces they provide. You learned how to create a Session object by using the IDBCreateSession interface of the DataSource object and how to create a Command object by using the IDBCreateCommand interface of the Session object. The section on Command objects includes a brief review of Structured Query Language (SQL). Examples also focus on using the OLE DB ODBC data provider to access a SQL Server data source.

In Day 19's lesson, you started with a discussion of the Rowset object and its associated interfaces. You brought together the concepts presented in the previous three lessons so that you could begin to make productive use of OLE DB.

You learned, on Day 20, three important topics in OLE DB application development: properties, transactions, and the Index object. Other topics covered include how to use properties to control the state of an object, the Transaction object, and the Index object.

In your final lesson in this book, you learned the mechanisms that OLE DB provides at multiple levels to integrate error handling into your applications. OLE DB uses the basic error-handling techniques of OLE Automation and adds another layer of error handling that can return multiple provider-specific errors. You learned how to integrate these techniques into your own applications.

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