Try not! Do, or do not; there is no try.—Yoda the Jedi Master, The Empire Strikes Back
Most applications need to “do” data. They need somewhere to store all the information for products, customers, purchases, samples, contacts, members, and so on. They also need to retrieve that information for use in the application, and apply changes to that information.
All of this is handled in the application’s data access layer. The data access layer can access data from any source, such as a configuration file, other external file, or database. Because the majority of applications use some type of database, this chapter focuses on building a data access layer to access a relational database.
When you build a data ...