The Build Match Group (BMG) process removes redundant matching in advance of the consolidate process. For example, suppose a base object had the following match pairs:

After running the match process and creating build match groups, and before the running consolidation process, you might see the following records:

In this example, there was no explicit rule that matched record 4 to record 1. Instead, the match was made indirectly due to the behavior of other matches (record 1 matched to 2, 2 matched to 3, and 3 matched to 4). An indirect matching is also known as a

transitive match

. In the Merge Manager and Data Manager, you can display the complete match history to expose the details of transitive matches.

If you use the Build Match Group (BMG) process, enable

Accept All unmatched Rows as Unique

in the match properties for the base object. If you do not enable

Accept All unmatched Rows as Unique

, the wrong value for rowid_match_rule appears in the HMRG table during transitive matching.