Model-driven development and OCL explained
You can use this guide to understand how a model becomes a working MDriven application before you build the Team Task Planner.
Model-driven development (MDD) means that you define the application in a model first. The model describes the data, relationships, business rules, and user interface behavior. In MDriven, that model is the central definition from which the application is produced.
When you add definitions in MDriven Designer, MDriven can generate database structures and user interfaces from the model. You do not write traditional database schema code or UI code for those generated parts.
| Instead of defining the same detail in several layers | Define it in the model |
|---|---|
| A database table for tasks, application code for tasks, and a form for tasks | A class with attributes such as Title, IsCompleted, and Priority
|
| Repeated calculation code for project progress | A derived attribute with an OCL expression |
This model-first approach keeps the application definition in one place.
What OCL does in this tutorial
OCL stands for Object Constraint Language. In MDriven, OCL expressions define queries, validation rules, and calculated values directly in the model.
OCL is the part of the tutorial where you express business logic in the model. Start with small expressions such as counts and selections. The model remains the place where the task-planner structure and these calculated values are defined.