Clarion Community Help

Introduction

Clarion is an infinitely adaptable environment, written to offer fast solutions at every skill level: from the business owner to the enterprise development team. Whatever your level coming in, Clarion will help you take control of your company data'more cost-effectively, and up to ten times faster than any other product out there today. Here's why'

Advanced code generator

Simply point to an existing database, or define a new one, and then use Clarion wizards to generate a full-featured business database application with advanced user interface functionality. The generated code includes complex features like multi-table joins, user authentication and access control, as well as functionality like filtering and sorting and reporting on any combination of database tables and records.

When you need a “business” application to maintain a database, you can literally do the job in minutes using Clarion. The key is the database dictionary. If the Application Generator knows what files or tables you want in the application, and how they're related, it can build an application. This is true regardless of where the files originated or in what format they are. So all you need to do is select one or more files, then indicate (when there are two or more files) the type of file relationships. The short Getting Started lessons herein demonstrate just how easy this whole process is.

The Application Wizard can then create a full-featured application using the Clarion default application metaphor. We call this the browse-form metaphor, and it extends directly from the structure of your database. The application works like this: (1) The end user navigates the database'all or part of it, one data file or multiple related data files'by scrolling through a list box, within which each item represents one record. The window in which this takes place is called a “browse.” (2) The end user selects a specific record in the list to perform an action, such as editing the data. This generally occurs in a separate window, in which the database fields appear in separate edit boxes. This is called an update “form.” A form may also accept new data. (3) Optionally, the end user can look up a value from a related table during form entry. This opens another browse in a separate window. The end user can select an item, closing the new window and placing the value in the edit box on the form, in one step. This is called a “lookup.”

That's the most general description. In addition, each browse window, navigable from the toolbar, opens on a separate thread with its own record buffer'which provides safer data handling. You can select among multiple key orders by CLICKING a tab. DOUBLE-CLICKING a record in the list opens an update form, with automatic concurrency checking (support for multi-user situations), and optional Referential Integrity constraint support (maintaining your database relationships).

Anybody can do this. It just starts with picking a data file from a list.

It's a visual development environment

With Clarion, dropping a control in a window gives you a lot more than other Rapid Application Development tools, which typically let you add a user interface control, but then expect you to write the code to implement its associated functionality. With Clarion, you add a template, which contains the control, and all its required data elements and executable code. That means you don't have to write code'one CLICK places a complete business solution: a user interface control, and the code that enables it to do its job. Moreover, each template has its own user interface. When you view the properties for the template, you'll see an “Actions” tab. By checking a box, choosing a dropdown list item, or filling in an edit box, you can customize the behavior of the template so that it meets your needs exactly. You'll set “actions” for the templates at many places in the upcoming lessons.. The lessons that follow in this document introduce you to all of the Clarion RAD tools.

When you use the template interface to specify these behaviors, the Application Generator writes the code (Clarion language source code) that implements the behavior for you'and the code it writes for you is object oriented, built from Clarion's Application Builder Class (ABC) Library, so the code is very compact and efficient. Using the templates, you can do an awful lot of custom programming without writing a single line of source code by hand.

The breadth and scope of the Clarion language can seem imposing at first. The Language Reference is several hundred pages. One of the great advantages of having the template system plus the ability to write code by hand is that you can ease into the language'as slowly as, as quickly as, as much as, or as little as you wish. If you don't like the way the templates solve a particular problem'you can use it at first, just to have something to do the job. Later, you can use the template interface, to modify it a little more to your liking. Finally, when you know the Clarion language, you can write a solution yourself, and have complete freedom to do it your way (Note: you can also buy third-party templates to solve problems yet another way).

Power users, who may not normally write programs, can easily do this.

It's a complete programming language

At the language level, you can quickly code an application using Clarion's fourth generation programming language. Clarion has a high level of abstraction, so that it's very “readable,” and a compact database grammar, so that you can easily manipulate data with standard language functions like ADD, GET, PUT and DELETE. You don't have to know Clarion to create an application' but if you do know how it works, it helps you understand what your applications are doing, and that helps you make better applications. One lesson has you write a small amount of your own Clarion code into the template-generated source, and another lesson introduces the Clarion language at a fully hand-coded level.

Professional developers will really appreciate the Clarion language. It was designed from the ground up for business programmers. Yet for its relatively quick learning curve (as a high-level 4GL) you'll get blazing performance. The SoftVelocity compiler technology turns all of your code'whether you wrote it or the Application Generator wrote it for you'into highly optimized machine code.

No matter which level you intend to work at, you're going to work a lot smarter if you first work through all of the lessons all the way to the end.

Continue to the Getting Started Lessons