Rowupdating event of the dataadapter
For the brief amount of time it takes to bind the data to your form and send it to the user, you have a potentially large amount of memory consumed by the s on a low-traffic site, this probably won't be of much concern.
However, as the number of concurrent users of your application increases, the more important this issue becomes.
For example, if the application will allow the user to undo delete operations, then you should use the objects to view your data—one using a filter that ignores rows marked as deleted, and one using a filter that only includes deleted rows.
I'll go into this in more detail in the section entitled "Sorting, Searching, and Filtering Data with Objects." If, on the other hand, you have no need to allow for the revocation of delete operations, then you can either remove or delete the row(s).
Here are the steps involved in defining such a class to handle the Figure 62 The Employee Maintenance menu for adding, editing, and deleting employee records Figure 63 The dialog for adding and editing employee records Table 61 DDX variables for the Employee Maintenance demo Finally we're done!
As I mentioned in the beginning of this chapter, while disconnected data is a wonderful thing for certain scenarios, it also increases the complexity of even something as simple as a maintenance application.
The four chapters you’ll be reading here showcase some of the new features of ADO. Chapters 8 and 9 show you how to access data and bind them to a Windows form using Visual Studio . Chapter 11 demonstrates how to use the same data access code to display data on Web forms using ASP. Lastly, chapter 18 shows how to create and manage database transactions using ADO. Specifically, in this hour, you'll learn how to object exists in memory and contains all rows returned by your query.
Like the never has more than a single database record in memory at any given time.
However, this book is also perfect for developers with some Microsoft .
NET experience and no knowledge of legacy Microsoft development platforms whatsoever. In this hour, you'll see an alternativeand in many instances more efficientmethod of retrieving data.
It does this by opening a forward-only, read-only stream of data from your data source.
The data provider contains the Connection, Command, Data Reader, and Data Adapter objects.I would encourage you to be very careful when using the Remove At method, since adding rows to and removing rows from the will have an impact on the ordinal value of the current rows in the collection.