Cannot successfully create a composite topic type

I need to create a composite topic type composed of several simple topic types. When connecting several simple topic types with this composite topic type, the arrow direction of the connecting line is different, and it can’t be modified many times, As a result, several simple topic types I need cannot be combined into one composite type I need.


Hello @zhlbb,

this probably results from the direction you chose when you created the associations of the composition definition. In your context, the arrows show which one is the parent type and which one is the child type. If you always drag the association from the child type to the parent type it will be correct. Thus, drag from your simple topic types to the main topic type of the composite.
You can see which ones are already correct by looking at the details of each association as in my screenshot. Please try to delete and redo the faulty ones.



Note: Since 5.x “Composite” topic types are named “Entity” topic types.

When modeling entities, you must be careful with how you model the association in between the entity (the parent) and its child types.

When modelling complex topic type definitions, the Entity must have set the role (Role Type) of Parent Type in the association. Conversely, the simple topic type (e.g. Number, Text, HTML, Boolean) must then play the role (Role Type) of a Child Type in the association. To change the roles of the types in the association, you can “Edit” the respective composition definition.

As @sme pointed out: The arrow should indicate the hierarchy of types, from parent to child type. Also, when creating associations between types, dmx automatically sets the role types in the association in relation to on which topic the user drags or drops the mouse/association handler.

I hope this clarifies modeling the relation between parent and child types.

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Thank you for your prompt. I ignored the direction of the connecting line. At present, the problem has been solved. Thank you for your kindness!

DMX lingo: composite means “is made of parts”. A parent is made of children.

A composite topic type is either an Entity type or a Value type.


Regarding association types: they can be composite too. However there is no entity/value distinction in this case: