5.1.3 RDML Practices
LANSA provides a powerful repository-based 4GL. The application architecture is based on a repository which shares and reuses information with the 4GL (RDML). Programming in a repository-based 4GL environment is not the same as coding with a 3GL. (Refer to LANSA RDML.)
It is possible to create 3GL style applications with any 4GL, but when you use 3GL techniques with a 4GL, you lose all of the benefits of the LANSA development environment. If you code validation rules in your programs or define all your variables within a function, this information cannot be shared or reused by other programs. Following are points to remember:
- Do not try to solve problems with 3GL approaches.
- Never translate 3GL code into 4GL code.
- Never translate 3GL "logic" into 4GL "logic".
It is important to focus on learning and implementing 4GL coding techniques and practices when building your LANSA applications.
Use the power of the combination of the repository and RDML. Remember that information in the repository can be shared and reused. The more information you place in the repository instead of the RDML programs, the more powerful your application becomes. Development productivity dramatically increases and maintenance efforts are significantly reduced.
Finally, two important, but often overlooked, aspects of designing, building and maintaining application systems are:
- The cost of developing a function rises very quickly as its complexity increases.
- The cost of maintaining a function rises even more quickly as its complexity increases.
Put simply, complexity costs! Do not over design or over build a function. Determine what functionality the user requires and the most efficient means of providing it. Expend your efforts where they will be most useful to the user. For more details, refer to the LANSA Application Design Guide.