Why is MDM important for SOA? Well there are a couple of reasons.
- MDM stops you having to do Single Canonical Form
- MDM helps you start from a point of federation
- Digital Landfill MDM
- Operational MDM
- Federated MDM
The first is the most common and is generally, in fact pretty much exclusively, a post-transactional approach where lots and lots of systems feed down into the "MDM" solution which is really there to provide the cross referencing required for a data warehouse reporting solution. These tend to be database centric and batch oriented and not overly useful for a real-time or operational environment
The second is where the MDM solution has actually taken on a transactional approach where information, for instance customer details, are actually held within the operational MDM solution and the cross referencing information is stored and available in real-time. This really is the minimum level at which an SOA environment should be operating. The MDM solution is there to ensure the loose coupling between services and making sure that a minimal reference model approach to information sharing can be handled.
The third is where there is no central MDM solution but it is still operating transactionally. This is the very very hard and not really to be attempted yet type approach. Here you can think about semantic web and those sorts of funky technologies and on doing the matching and cross referencing on an on demand basis. I'm pretty sure this type of solution won't work very well, or indeed potentially at all, but its really what lots of people are trying to do today when they have an ESB, lots of services and nothing set up to do the mappings.
So basically the point is simple. A transactional, operational, real-time MDM solution is an absolute requirement for a professional SOA environment. Without it you are going to have nasty tight integrations between areas at the data layer or some amazingly complex mappings that will fail on a regular basis. I'm not even talking here about the benefits of data quality improvements by using a decent MDM solution I'm just talking about something that manages the cross-referencing of similar information between systems and services.
The odds are however that in doing your SOA solution you've left MDM being something that just feeds the data warehouse and looks at reporting.