Creating a Logical Model
Logical model is used to set up almost all objects in the MDM Hub, which are generated from metadata descriptions of all entities, relationships, and settings. It consists of several other models describing particular data layers. The Instance Layer is usually used as a canonical interface for all connected systems.
There exist different approaches to creating the model and different modeling CASE tools. MDM in ONE Desktop has CASE capabilities and the Import feature for either Instance or Master Layer model, so it can be easily uploaded into an MDM project from different formats (for example, XMI, Sybase PowerDesigner).
There are two different modeling approaches:
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Bottom-up approach
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Top-down approach
Bottom-up approach to creating a logical model
Bottom-up approach defines the MDM Hub canonical model according to the entities and attributes of connected systems, hence it is easier to map the data between the systems and the Hub. However, mapping from the Instance to Master Layer model can be more complicated.
The following steps are usually taken:
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Understand models of connected systems and their possible output interfaces.
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Define the Instance Layer model as a superset of models of connected systems.
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Based on the Instance Layer model, define the Master Data Layer model.
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Validate output interfaces defined by the Master Data Layer model with consuming systems and connected applications.
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Changes might be necessary because of the requirements of consuming systems.
This approach is preferred if the MDM initiative is driven by the connected systems (from the architecture or sponsorship perspective).
Top-down approach to creating a logical model
Top-down approach is probably a "cleaner" design from the MDM perspective as the model is derived from the Master Layer (or the Golden Record) viewing requirements.
The following steps are usually taken:
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Make a list of users of the MDM solution; these might be systems, applications, business users, and departments.
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Understand the needs and goals of those users.
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Define the Master Data Layer model to satisfy those needs and meet user goals.
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Based on the Master Data Layer model and the output interfaces of connected systems, define the Instance Layer Model.
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Changes might be necessary as some needs and goals might be impossible to realize because of output interfaces of connected systems.
This approach is preferred if the MDM initiative is driven by the future users of the MDM solution (from the architecture or sponsorship perspective).
How to create a logical model in MDM
There are several options for setting up a logical model in MDM:
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Importing - See Importing a Logical Model.
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Creating from scratch - See Creating an Instance Layer Model and Creating a Master Data Layer Model.
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First importing and then tuning in ONE Desktop.
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