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DB design:
Example:
Feed - h1 (create), h2 (create), h3 (create), h1 (updated occupation), h1 (updated nid2), h2 (voided, merged-with h3), h4 (create), h5 (create).
All have same NID, nid1 but different catchments, c1, c2, c3, c4, c5. Also, h4, h5 have same phone #.
Rules: same nid and same phone # are dedups. Dedups cannot be resolved for just one rule, but for all.