You can use orderDescending in an OCL expression to sort a collection from the highest value to the lowest value; it is for developers defining ordered results in MDriven Designer.

Syntax

collection->orderDescending(iterator | sortExpression)

Part	Meaning
collection	The collection to sort.
iterator	A temporary name for each object in the collection.
sortExpression	The attribute, or supported path of attributes, used as the sort key.

The result is the same collection ordered in descending order. For text values, this means reverse ascending order; for numeric or date values, the largest or latest value appears first.

Sort cars by name

Given a Car class with a Name attribute, sort a collection of cars by name from Z to A:

Car.allinstances->orderDescending(car | car.Name)

For cars named Alpha, Roadster, and Zephyr, the result order is Zephyr, Roadster, Alpha.

Sort by a number or date

Use the value that defines the order as the sort expression. For example, to show cars with the highest mileage first:

Car.allinstances->orderDescending(car | car.Mileage)

To show the most recently registered cars first:

Car.allinstances->orderDescending(car | car.RegistrationDate)

Order by related information

The sort expression can follow single links to reach an attribute on a related object. For example, if each car has one Owner and an owner has a Name attribute:

Car.allinstances->orderDescending(car | car.Owner.Name)

Be aware that ordering through related information uses a join. It is not an outer join: a car without the required related data is excluded from the result set.

Choose the correct ordering operator

Use orderDescending when the highest, latest, or reverse-alphabetical values must appear first. Use orderBy when you want ascending order instead.

See also

• Documentation:OCLOperators orderBy
• Documentation:OCLOperators minValue
• Documentation:OCLOperators maxValue
• Documentation:OCL General Operators