Table Orientation

The specification of the decision table allows the rules to be listed either horizontally or vertically to accommodate different user's preferences for the orientation of the table. This flexibility is simply a question of presentation and the different orientations do not in any way affect the logic or semantics of the rules or the inputs and outputs of the decision table. So a table with horizontally listed rules is logically equivalent to a table with rules listed vertically. Enterprise Architect has a helpful facility to change the orientation of the table. This is very useful, particularly when demonstrating the rules to an individual or to a group of stakeholders during a workshop where one or more of the stakeholders might find it easier to view the rules in a particular orientation.

The orientation can be changed by simply selecting the 'Rotate decision table' icon on the DMN Expression window toolbar.

This is a toggle icon and selecting it again will simple revert the table to its original orientation. As suggested earlier, if you are working with colleagues who are unfamiliar with DMN or logic rules in general and who seem to be struggling with understanding the decision table, it is worth toggling the orientation and seeing if that helps them.