Introduction:

In my previous blog, I detailed about different types of project dependencies. 
This is a follow-up blog, in which I will detail on the topic of Enforced dependency vs Flexible dependency, and illustrate the different behavior using ENOVIA Project Planning application.  

Dependencies in general, are schedule constraints, which define the relationships between different tasks, determining the order in which they are executed and how changes in one task may affect others. 

The dependency mode (Enforced or Flexible) will affect how tasks will automatically move when any changes are made to the tasks that they are dependent on.

Enforced Dependency:

Enforced dependencies often manifest in projects where tasks are tightly linked in a sequential manner. 

When working with Enforced Dependencies, a change of the date of a task, will automatically change the date of the dependent task in the same way.

For example, in the case of Finish to Start dependency between task A and task B:

Task B cannot start until task A is completed, creating a clear dependency between the two. When the start or end date of task A changes, the dates of task B will change accordingly. 

Review the video to understand the behavior of Enforced Dependency in Project Planning app:

Flexible Dependency:

Flexible dependencies are also known as discretionary dependencies or soft dependencies. 

In the ENOVIA Project Planning application, Flexible dependency is shown as a dotted line in the Schedule View.

Unlike Enforced dependencies, Flexible dependency does not automate planning updates to satisfy the constraint. The dependency is solely displayed, without making any changes to the tasks dates, even if there is a dependency conflict. 

Review the video to understand the behavior of Flexible dependency in Project Planning app:

Broken Dependency:

Broken dependency is a dependency conflict, and it refers to a situation where there is a clash or inconsistency in the relationships between two tasks. 
In case of a broken dependency in Project Planning application, the dependency is displayed in red, indicating that a manual intervention is required.

Broken dependency can also occur in a flexible dependency situation, where the condition is not met (as seen in the Flexible dependency video), or in an enforced dependency where the system has not found a way to satisfy the constraint, as illustrated in the below video: