MDM: It’s Not about One Version of the Truth by Michele Goetz.
From the post:
Here is why I am not a fan of the “single source of truth” mantra. A person is not one-dimensional; they can be a parent, a friend, a colleague and each has different motivations and requirements depending on the environment. A product is as much about the physical aspect as it is the pricing, message, and sales channel it is sold through. Or, it is also faceted by the fact that it is put together from various products and parts from partners. In no way is a master entity unique or has a consistency depending on what is important about the entity in a given situation. What MDM provides are definitions and instructions on the right data to use in the right engagement. Context is a key value of MDM.
When organizations have implemented MDM to create a golden record and single source of truth, domain models are extremely rigid and defined only within a single engagement model for a process or reporting. The challenge is the master entity is global in nature when it should have been localized. This model does not allow enough points of relationship to create the dimensions needed to extend beyond the initial scope. If you want to now extend, you need to rebuild your MDM model. This is essentially starting over or you ignore and build a layer of redundancy and introduce more complexity and management.
The line:
The challenge is the master entity is global in nature when it should have been localized.
stopped me cold.
What if I said:
“The challenge is a subject proxy is global in nature when it should have been localized.”
Would your reaction be the same?
Shouldn’t subject identity always be local?
Or perhaps better, have you ever experienced a subject identification that wasn’t local?
We may talk about a universal notion of subject but even so we are using a localized definition of universal subject.
If a subject proxy is a container for local identifications, thought to be identifications of the same subject, need we be concerned if it doesn’t claim to be a universal representative for some subject? Or is it sufficient that it is a faithful representative of one or more identifications, thought by some collector to identify the same subject?
I am leaning towards the latter because it jettisons the doubtful baggage of universality.
That is a subject may have more than one collection of local identifications (such collections being subject proxies), none of which is the universal representative for that subject.
Even if we think another collection represents the same subject, merging those collections is a question of your requirements.
You may not want to collect Twitter comments in Hindi about Glee.
Your topic map, your requirements, your call.
PS: You need to read Michele’s original post to discover what could entice management to fund an MDM project. Interoperability of data isn’t it.