18 August 2015

OpenIDM: Relationships as First Class Citizens

One of the most powerful concepts within OpenIDM, is the ability to create arbitrary managed objects on the fly, with hooks that can be triggered at various points of that managed objects life cycle.  A common use of managed objects is to separate logic, policy and operational control over a type of users.  However managed objects need not be just users, commonly they are devices, but they can also be used to manage relationship logic too - similar to how graph databases store relationship data separate to the entity being managed.

For example, think of the basic relationship between a parent and child (read this article I wrote on basic parent and child relationships). That article looked into the basic aspect of storing relationship data within the managed object itself - basically a pointer to some other object managed in OpenIDM.

That in itself is powerful, but doesn't always cover more complex many-to-many style relationships.


The above picture illustrates the concept of externalising the relationship component away from the parent and child objects.  Here we create a new managed object called "family".  This family basically has pointers to the appropriate parents and children that make up the family.  It provides a much more scalable architecture for building connections and relationships.

This model is fairly trivial to implement.  Firstly, create the 3 new managed object types via the UI - one for parent, one for child and one for family.  We can then look at adding in some hooks to link the objects together.  I'm only using onDelete and postCreate hooks but obviously more fine grained hooks can be used as necessary.




A basic creation flow looks like the following:

  1. Parent self-registers
  2. Via delegated admin, the parent then creates a child object (the creation of the child is done via an endpoint, in order to get access the context object to capture the id of the parent creating the child on the server side)
  3. After the child is created, the postCreate hook is triggered, which creates a family object that contains the parent and child pointers
  4. Once the family object is created, the family postCreate hook is triggered, to simply update the parent and child objects with the newly created family _id
That is a fairly simple flow.  The family object can be read just via the managed/family/_id endpoint and be manipulated in the same way as any other object.  A useful use case, is to look for approvers on the child - for example if the child wants to gain access to something, the family object can be looked up either for parallel approval from both parents or just via an explicit approver associated with the family.  

Another use case, could be when a new parent registers and wants to "join" a particular family - the approver on the family object can be sent an "access request" and approve as necessary.

The flow when a parent or child object is deleted is similar in it's simplicity:
  1. Parent (or child is deleted) perhaps via de-registeration or admin performing a delete
  2. The parent onDelete hook triggers, which finds the appropriate family object and removes the child or parent from the array of parents or children
When a family object is deleted, again the flow is simple to interpret:
  1. Family object is deleted (via an admin)
  2. All parents and children found within the family object, are looked up and deleted
This provides a clean de-provisioning aspect.

Obviously each managed object can also have it's own sync.json mappings and links to downstream systems the same as a non-relationship based deployment.

Another common set of use cases is around consumer single views.  For example, the relationship object becomes the consumer, with all other managed objects, such as preferences, marketing data, sales history, postal addresses and so on, all being linked in the same manner.  The consumer object becomes the single entry point into the data model.









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