Nodes and edges

Note The images in this topic show the old diagram user interface. You can still refer to them to understand the concept.

Nodes and edges are the fundamental building blocks of diagrams and diagram views:

• In diagrams, nodes are rectangles or circles that represent, respectively, assets or complex relations. Edges represent relations between assets or between assets and complex relations.
• In diagram views, nodes are rectangles or circles that represent, respectively, asset types or complex relation types. Edges represent relation types between asset types or between asset types and complex relation types.

Both nodes and edges can be represented in different ways in diagrams and diagram views.

Relations connect assets, or assets and complex relations. In diagrams, this is represented by edges that connect nodes. Each node can have incoming and outgoing edges:

• An edge of a node is incoming if that node is the "to" node of the edge. This depends on the relation type and the direction of the edge:
  • The node is the tail side of the relation type, and the edge has the role direction.
  • The node is the head side of the relation type, and the edge has the co-role direction.
• An edge of a node is outgoing if that node is the "from" node of the edge. This depends on the relation type and the direction of the edge:
  • The node is the head side of the relation type, and the edge has the role direction.
  • The node is the tail side of the relation type, and the edge has the co-role direction.

Node and edge styles

Edges represent relations, which in turn describe a link between assets. To represent the meaning of those links in a diagram, edges can be represented in different ways. Depending on the meaning of the relation, you can choose which edge style suits best.

• Arrow: The most basic way to represent an edge is by means of an arrow. This representation is ideal for visualizing flows and causal relations.
  
  Example 

  

• Boxed and boxing: Many relation types are used to describe a part-whole relation, such as "Tableau Project groups / is grouped by Report". For that reason, you can also represent the relation between those assets as boxing nodes and boxed nodes.

  A node that has an outgoing edge of the boxing style, becomes a boxing node. For the boxed node, the same edge is an incoming edge of the boxed style. Additionally, one boxing node could contain several boxed nodes, which have edges of their own.
  

  Boxing nodes can be expanded or collapsed:

  • An expanded boxing node shows its boxed nodes.
    You can collapse them by clicking in the upper right corner of the node.
  • A collapsed boxing node does not show its boxed nodes. As a consequence, if the hidden boxed nodes have arrow edges to nodes that are not contained by the boxing nodes, the diagram shows them as arrow edges of the boxing node.
    You can expand them by clicking in the upper right corner of the node.
  • A locked node is a collapsed node that cannot be expanded.
    You can recognize locked boxing nodes by the in the upper right corner. You can still explore the nodes to see the edges.
Example 

Duplicate nodes

In some cases, the same asset might be represented by more than one node. In other words, there are two nodes representing the same asset, on the same diagram. This can be caused by several of reasons, but the most common reason is that an asset matches more than one node of the diagram view.

A node in a diagram view represents an asset type or a complex relation type. In the result diagram, this node represents an asset of that asset type or an asset of a child asset type. As a result, if a diagram view contains a node for an asset type and a node for its child asset types, the result diagram may contain an asset of the child asset type that matches both nodes of the diagram view. Therefore, the asset node is duplicated.