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11.21.06
Using DataTables More For Improving Performance
 By Mads Kristensen
There are some features in the System.Data.DataTable class that a lot of developers don't utilize.
I base that statement on different code samples I've seen on blogs and article bases during the last couple of years. Some of these features can improve the performance.
Calculated columns
First of all, I'll create a DataTable manually, even though it is more likely to be created from querying a database.
Imaging that there is 100 rows in that DataTable and you now want to calculate total price of all item currently in stock. The calculation is Price*ItemsInStock. What I see in a lot of code samples is that this column is calculated in the database by a SQL statement like this:
The overhead in letting the database do the calculation is not that much in this particular example, because it is a simple multiplication of two rows. It could easily be more complicated than this example. The thing is, that .NET performs these kinds of calculation much more efficient than a database and that's why we would like .NET to do them.
The DataTable class supports on-the-fly calculated columns and they are perfect to use in the example. Just add another column to the DataTable and give it a calculation formula.
There a many different functions to use in the calculation expression.
Auto increment
Let's say you want to bind the DataTable to a DataGrid in an ASP.NET page and that you want a column to display the row number. This can be done by adding a column to the DataTable that has enabled the AutoIncrement property.
Click here to continue reading this article.
About the Author:
Mads Kristensen currently works as a Senior Developer at Traceworks located
in Copenhagen, Denmark. Mads graduated from Copenhagen Technical Academy with a multimedia degree in
2003, but has been a professional developer since 2000. His main focus is on ASP.NET but is responsible for Winforms, Windows- and
web services in his daily work as well. A true .NET developer with great passion for the simple solution.
http://www.madskristensen.dk/
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