You are viewing the documentation for Blueriq 15. Documentation for other versions is available in our documentation directory.
What is it?
A relation describes the association between two entities. The relation is reversible; from entity1 towards entity2 and from entity2 towards entity1. This reverse relation is required.
For instance, if ‘Person’ and ‘Job’ are both entities, a relation ‘HasJobs’ can be created from ‘Person’ to ‘Job’. The reverse relation ‘IsOfPerson’ can be created from ‘Job’ to ‘Person’.
How to – define a relation
When creating a relation you need at least one or more entities.
- Select the Home tab
- From the Domain group select the Relation icon
- Fill in the required fields and tick the necessary boxes
- Add a validation if desired
- Click Save or Save & close
Properties
| Property | Description |
|---|---|
| Functional name | Optional, can be used in Documentation |
| From entity | Choose the entity from which the relation originates. |
| Relation | Name the relation |
| Multi-valued | Tick this box if the relation can be multi-valued |
| To entity | Choose the entity the relation points to. |
| Reverse relation | Name the reverse relation |
| Multi-valued | Tick this box if the reverse relation can be multi-valued |
| Default value | Using the default value to set a relation will cause the inference engine to automatically determine the instances linked in the relation. You are able to create an expression here to select these instances. |
| Description | Is optional, but recommended. |
| Question text | Fill when the relation should be visible to the user |
| Explain text | Provides additional explanatory text. |
| Validation rule | Choose one or more validation rules. Validations check the correctness of the input for that relation at run-time. First you have to create a validation rule in order to be able to choose it here. Validation rules can also be added to a relation by dragging and dropping. |
| Validation type | The following validation types are available:
|
Creating and maintaining relations
Relations between instances can be created and maintained in several ways.
Service calls
Relations can be managed using the following service calls:
Adding a relation to a containment
By adding a relation to a Page or Container, a 1:1 relation can be created and/or read out between active instances or between an active instance and a newly created instance.
Default value
Using the default value to set a relation will cause the inference engine to automatically determine the instances linked in the relation. Take note when using the relation its default expression is evaluated to determine all instances that will be present in the relation. The truth maintenance system ensures that any change in the profile that affects the outcome of the expression will cause the relation to be re-evaluated.
Manually setting the relation will take precedence over the inferred instances (inferred value is system set, using services to set the relation makes it user set).
Reverse relation
We strongly discourage using the reverse relation of relations with a default value in any way, as this can cause performance issues.
Overview
Content Tools
1 Comment
Ronald Peterson
I'm trying to understand when using the reverse relation of relations with a default causes performance issues. Is this caused by the fact that in order to determine the value of the reverse relation the expression has to be evaluated for each instance of the entity the reverse relations points to?
Furthermore I'm wondering if the values of the derived relations are cached? And thus only re-evaluated if an attribute used in the expression changes value.