In our previous post, we explored how a single Party can perform multiple roles within a business.
But those roles are not necessarily permanent.
A person may become a customer, later accept employment with the same company, and eventually leave that employment while remaining a customer.
The person is still the same individual. What has changed is the role, or combination of roles, that the person performs.
Roles Have a Lifecycle
A Party Role may begin, change, or end without changing the Party’s underlying identity.
Consider someone who:
- Becomes a customer.
- Accepts employment while remaining a customer.
- Leaves employment but continues as a customer.
- Returns as an employee several years later.
The person remains the same, even as their roles change over time.
Depending on the business requirements, the model may need to represent multiple periods during which the same Party performed a particular role.
Why Does Time Matter?
Business systems often need to answer questions about both current and historical activities.
- Who was an employee on a particular date?
- When did an organization become a supplier?
- Was someone acting as a customer, employee, or both when a transaction occurred?
If our model represents only current roles, we may lose the ability to answer these questions accurately.
One common approach is to record when a Party Role becomes effective and, when applicable, when it ends.
The appropriate level of historical detail depends on the business requirements. Not every system needs to preserve the same information.
What Happens When We Get This Wrong?
When identity and role are combined, ending a role may inadvertently remove or obscure information about the Party.
We may also create duplicate records when someone returns to the business in a different capacity.
Both situations make it more difficult to maintain accurate information and reconstruct historical business activities.
The Key Point
A Party’s identity can remain consistent even as its roles change over time.
Separating Party from Party Role allows us to represent changing participation without unnecessarily creating new identities or losing information about existing ones.
Before designing how a role will be represented, ask:
Do we need to know only the Party’s current role, or must we also know when that role was active?
Next in This Series
In our next post, we’ll examine how people and organizations are connected to one another.
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