| OCL statement | can be used for automatic code generation |   | 
can consist of - References to role names, association names, attributes and the results of operations.
 - The logical values true and false
 - Logical operators such as and, or, =, >, < or <> (not equals)
 - String values such as: 'a string'
 - Integers and real numbers (the latter having a decimal point)
 - Arithmetic operations *, /, +, - 
 
  |   | 
| can navigate from class to class using a dot to separate components. For example, in LinearShape, to refer to the length of the edges you can refer to edge.length. |   | 
| can refer to all the values in a collection using the forall operator |   | 
| can refer to special OCL properties of a collection itself using the -> operator |   | 
| can use the {ordered} constraint to indicate that an OCL collection is a sequence, which allows you refer to special properties such as first and last |   | 
| can use the implies operator which is true if either the left hand side is false or if both sizes are true |   | 
| does not have to be written on a UML diagram but can be written separately with a context specified |   | 
| has example {startPoint <> endPoint} constrains the two ends of a LineSegment to be different |   | 
| is a subtopic of 5.6 - More Advanced Features of Class Diagrams |   | 
| is not compiled |   | 
| is not executed |   | 
| is a kind of statement |   | 
| specifies a logical fact (a constraint) about the system that must remain true |   | 
| statement | should be not more than one line long if possible |   |