You can use isDirty in OCL to determine whether an object has changes that have not been saved, for example when an expression must react only to edited objects.
Syntax
self.isDirty
isDirty returns a Boolean value:
| Result | Meaning |
|---|---|
true
|
The object has changed since its last save. |
false
|
The object has not changed since its last save. |
Example
Use self.isDirty when the expression concerns whether the current object has unsaved changes.
self.isDirty
For example, an expression using this operator evaluates to true after you change a value on the current object and before those changes are saved. After the object is saved, it evaluates to false until another change is made.
Check one attribute instead
isDirty checks the object. If you need to determine whether one specific class attribute has pending changes, use IsDirtyMember on that attribute.
Use with save actions
Save commits changes from a ViewModel to persistent storage. Use isDirty to test for changes before that save has occurred.
If you need to perform an action whenever an object is being saved, use OnUpdate. OnUpdate runs immediately before the object is saved; it is not a replacement for an expression that tests whether the object is currently dirty.
Related operators
IsNew answers a different question: whether the object has ever been saved to the database. An object can be new, while isDirty indicates whether it has changes since its last save.