Design patterns are a very widespread theme in technical literature, regardless of the programming language proposed. At the beginning of this chapter, a little bit of information about the concept, and various types of patterns (such as the creative, behavioral, and structural patterns and the GoF standard), were presented.
The theme of the chapter was then presented, and the challenge began—building a multi-database application with a little effort, using at least one design pattern and some interfaces in Delphi.
For the database, some servers were proposed: SQL Server Express and PostgreSQL. Database installation was not covered, but we demonstrated how to create new tables using SQL Server Management Studio and PostgreSQL pgAdmin with SQL scripts. A database named packt, with the tables users, customers, and products, was created; then, we need a class that...
