Please note : This help page is not for the latest version of Enterprise Architect. The latest help can be found here.


Constraint Composition:

Constraints are composed using member and local variables in expressions separated by operands such as:


The following is an example Conditional expression that returns a Boolean True/False:

( (x%2) > 1) AND (y >= 10) )


Variables can be scoped by either  '.' or '->'

c.Name  :  c.Names[0] of an array as  c.Names[0].Surname= "Smith"


There are two types of operators you can use on constraints:

Logical operators AND and OR can be used to combine constraints
Equivalence operators '=' and '!=' can be used to define the conditions of a constraint


All constraints are subject to an AND operation unless otherwise specified; you can use the OR operation on them instead, for example:

Location=0 OR

Location=1 AND



(a AND b)

(a.b AND ( b.a OR c.a))


Below are some examples of using the equivalence operators:


m_value <> 0





Quotes around strings are optional; the comparison for strings is always case-sensitive in determining the truth of a constraint

Learn more


Learning Center topics

(Alt+F1) | Execution Analysis | Testpoints | About Constraints
(Alt+F1) | Execution Analysis | Testpoints | About Statements