TABLE OF CONTENTS A small-scale asset management application can be designed using the client-server model. Each client includes the presentation and business logic. The server is essentially a database. All inter-process communication between clients takes place via the database using triggers and stored procedures. Although some simple and elegant systems based on this architecture are in use today, such systems do not offer the performance and scalability of a multi-tiered architecture. The limit comes at around 100 clients. At this point, the number of database connections leads to queuing and inefficiency. The other drawback is that any changes to the application logic entail updates to every client.
In Figure 12.1, if client 2 needs to communicate with client 1, then that takes place through data tables. Each client can also access the file and media servers to view or retrieve assets.
The developers of enterprise software applications have long realised that affordable products required a new approach to software design. The monolithic sequential logic of the old main-frame application had many drawbacks. The debacle of the two-digit dates at the turn of the century demonstrated the advantages of object or component-based design. To modify a date component was trivial, to modify date logic embedded in thousands of lines of code was fraught with problems.
The favoured architecture proved to be multi-tier, with an application server based on object-oriented design.
There are a number of compelling reasons why a multi-tier approach, based upon an application server, offers...
