Within an enterprise distributed system I have many services - an E-commerce service, a CRM, support desk, finance, billing. Many of these services share common data, such as
These services communicate with each other using an Enterprise Service Bus (ESB) to ensure that data in all systems is eventually consistent with one another.
My question is this: Is it better to ensure that only one system can update any one part of data? To have a single source of truth. E.g. Only the billing system can update the Customer's billing information. Only the CRM can update the Customer's contact details?
To me this sounds cumbersome and confusing to locate the correct system for the data that you wish to update. I can see it better to have multiple sources for updates and the ESB communicates these updates to subscribed services.
I can see that some data will have a single source of truth (SSOT) as it would be quite niche, such as Customer's credit card information, for example.
What is an commonly adopted technique for dealing with common data that could potentially be updated from different services? Is a SSOT needed in an enterprise distributed system?