Source System Management (SSM) maps records in the TCA Registry with the source system that the data comes from. See: Source Systems Overview.
For D&B, the D-U-N-S Number is used as the source ID, which identifies the record in the source system. Each record from D&B with a unique D-U-N-S Number can map to only one party record in the TCA Registry. Likewise, if multiple parties in the Registry has the same D-U-N-S Number, only one of those records can be mapped to D&B. The party that is actively mapped to D&B has what is called the mapped D-U-N-S Number.
Attention: When you repurchase D&B data through batch load, and several parties have the same D-U-N-S Number, only the party with the mapped D-U-N-S Number is updated.
For both online purchase and batch load, when you acquire D&B data with a D-U-N-S Number that does not yet exist in TCA, the party is automatically mapped to D&B. For example, you get D&B data for Vision Corporation for the first time, including the D-U-N-S Number for Vision. If that D-U-N-S Number is not already mapped, then Vision Corporation is created as a new party, with the mapped D-U-N-S Number.
If you repurchase D&B information for Vision Corporation, and D&B provides a different D-U-N-S Number, then Vision gets a new, mapped D-U-N-S Number.
You can also later acquire D&B information with the same D-U-N-S Number for another party, but only one of the two parties can have the mapped D-U-N-S Number. The mapping would automatically switch to the party that you are working with. For example:
You are acquiring D&B information for Vision Corporation for the first time, and you get D-U-N-S Number A for Vision. Another party, however, already has that D-U-N-S Number and is mapped to D&B. The existing mapping would be inactivated, and Vision would get the mapped D-U-N-S Number.
You are acquiring D&B information to update Vision, which currently has D-U-N-S Number A. D&B provides D-U-N-S Number B to update Vision, but another party already has D-U-N-S Number B and is mapped to D&B. Again, the mapping for D-U-N-S Number B would go to Vision.
D-U-N-S Number A is no longer a mapped D-U-N-S Number, until you purchase D&B data with D-U-N-S Number A for a party.
Suggestion: Multiple parties with the same D-U-N-S Number are allowed to support different company situations. You should use the shared D-U-N-S Number to identify and merge duplicates, since only the record with the mapped D-U-N-S Number is updated through batch load.