Additionally, it can perform tasks like enforcing security and carrying out validation, as you saw in part two of this article series.
The data access layer contains the code that directly interacts with the data source, a SQL Server database in the case of the Contact Person Manager application but this could be any other kind of data source, like text or XML files, Access, Oracle, DB2 databases and any other data source you can come up with.
If you haven't read part one or two yet, you should really read them first, as this article uses many concepts that have been explained in part one and two.
In the Download for this application you also find the SQL Scripts to recreate the database on SQL Server 2000 or SQL Server 2005.The , while the other points to a database on a commercial version of SQL Server 2000 or 2005.You also saw how to use the API to programmatically create contact persons and their contact data and save those in a database.However, writing explicit code to work with your business objects isn't always fun, and can be a cumbersome task.Part two showed you how to code the classes that were designed in part one.
You saw how to implement the data access methods and database code and how the various classes were able to work together.
Refer to this article about configuring SQL Server 2000 or 2005 if you need more information about using this second connection string.
The controls in the site will return to their default layout.
All they can do, is hold and expose data through their public properties.
Additionally, each BO object has a List counterpart, like and are used to hold collections of the business objects.
With the additional files in the site looked at, let's take a look at how you can display contact persons on a page.