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Adding a relationship

A relationship establishes a link between concepts. To use the Relationship tool in the toolbox, there must be at least two concepts in the diagram. Click on the Relationship tool and then move the mouse pointer onto the canvas.

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A relationship connects one concept with another. Begin by identifying the initial concept that you want to connect and then click on it. Next, gently move the mouse point slightly away from the concept. An arrow will appear, and you will see that the relationship anchors to the first concept.

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Move over to the second concept and click on it to establish the relationship. Notice the label for this relationship.

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Relationship element

Relationship elements are commonly used when modeling property graph schemas. The default label for a relationship is label. You can rename it the same way you would a concept: simply double-click on the label and type in the new name.

The lower section of the relationship shows the number of attributes attached to this relationship. By default this value is zero.

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Add a relationship and a new concept

You can also create a relationship between an existing concept and an as-yet-uncreated concept. Select the existing concept on your canvas, click on the + menu and choose either Add To New Concept or Add From New Concept.

 

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hoose Add To New Concept to add the relationship with the arrow pointing from the original concept to the new concept.

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Choose Add From New Concept to add the relationship with the arrow pointing back toward the original concept.

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Detailed relationship information

Select a relationship on your canvas to view detailed information about it in the left side panel. This panel contains all of the fields for all connected concepts, the relationship, and Advanced information. The fields for relationships function exactly the same as for concept,s except for the IRIs. If a new relationship has the same label as an existing relationship, the relationship will also have the same IRI.

Note

The number in parentheses adjacent to the element type—for example, CONCEPTS (2), or > RELATIONSHIPS (1)—indicates the number of other elements that connect to this element. In the figure below, a single relationship connects to two concepts.

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Cardinality

You can specify cardinality for relationships. Suppose you have a Business concept that connects to an Address concept by means of two relationships: has address and has shipping address’.

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Suppose also that a Business may have multiple addresses and does indeed have at least one location address. However, there is a constraint that this business may only have one shipping address for all shipments.

For this example, you would set the Cardinality for the has address relationship to be min , 1.

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The Cardinality for the shipping address relationship would be exact , 1.

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Relationship cardinality export

Relationship Cardinality is exported as an owl:Restriction on the appropriate Class.

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Self-referencing relationships

If you would like to relate a concept to itself, you can add a self-referencing relationship with the Relationship tool from the toolbox. Click on the concept, and then click again on the same concept to set it as the destination. Your diagram should look like the figure below.

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