Erik Pepping - Clarion for Windows, the Preferred Client/Server Development Tool

Posted September 1 1997

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So, you're thinking about moving your database applications to a Client/Server platform? You know it's the latest rage in database developments, but you're just not sure if your Clarion applications will work as well with an SQL back end as with the TopSpeed files. Well, if you ask Erik Pepping, there is no question... move to an RDBMS and use SQL.

Erik took the attendees of his breakout session on a 50-minute tour of the differences between the Record and Set oriented file systems, basic client/server theory, implementation of Client/Server in Clarion for Windows, and finally a demonstration of an application in production.

Clarion began as a record based file system - one record accessed and processed at a time. The set orientation, which is the client/server approach, operates on an entire group of data. According to Eric, Clarion resisted this type of implementation for many years while other products such as Visual Basic and PowerBuilder latched onto the concept early.

The benefits of a set oriented database over a record based system include smarter retrieval of data, better performance, scalabilty of hardware, security of data, and better implementation of business rules. Example code demonstrates that SQL can do in one SELECT statement, what it would take a page of Clarion code to accomplish in the record model. Besides being more economical in selection code, the client/server model is extensible from PC's to Mainframes, DOS to UNIX and more secure than the standard record based model. RDBMS files are not easily accessed outside the confines of the allowed system defined rights. Record based systems are much more susceptible to security problems, stated Erik.

Erik's personal experience seems to focus mostly on Oracle, so the discussion focused mostly on knowledge gained by using the Oracle C/S architecture. For anyone in the audience who has ever struggled with getting the right Oracle files installed, a brief summary of the necessary .dll's and installation settings was provided.

After laying the foundation of a C/S back end, an evaluation of some front end programming tools was presented. The three tools that were considered for the project were Visual Basic, PowerBuilder, and Clarion.

Visual Basic requires ODBC, which slows the data access. It also requires quite a few add-ons to make it work well. In addition, VB requires the standard Windows .dll's, which can be overwritten with newer versions by many other programs. These version switches can cause the application to stop performing correctly.

PowerBuilder, according to Erik, has a very steep learning curve and a lot of add-on utilities that are required to make applications functional. In addition to learning times, the distributable application requires a fairly large run-time library and runs rather slow.

Erik's choice for a development tool is Clarion. With the small run-time libraries (or none if compiled locally), the Clarion application footprint is smaller and the application is faster than the other products evaluated. As far as add-on products are concerned, the SQL templates by CCS are highly recommended and the only ones needed. Certain features in the template code allow the standard Clarion browse to work faster in the C/S environment. Sorts are available on any field by simply clicking the column in the browse box and a useful QBE window is included.

To close the presentation, an application written in Clarion using Oracle as the data source was demonstrated. The application highlighted some of the best features of the SQL back end database. Erik showed a query-building screen and created an ad hoc query that reported back data on a table that contain hundreds of thousands of records within seconds. Any concerns about performance were squashed with that demonstration. Tips were given on how to optimize select statements to give the quickest results.

One of the most fascinating bits of code presented in the application was the report designed to display data. The report code consists of a well-designed Select statement and a single loop to print the detail lines. This method of reports essentially cuts the Clarion report code down to a half a page. It is an interesting implementation and the audience was impressed by the unique approach.

Erik Pepping's presentation shows that Clarion applications are definitely ready to interface with the Client/Server world and they can do it faster and easier than other products available.

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