Repairs trial_run.course_id, trial_run.runner_id, trial_run.jockey_id and trial_run.trainer_id, sourced from tblbarriertrials.BCourseID / BHorseID / BJockeyID / BTrainerID. Barrier Trials resolves these once at insert time and never revisits an already-migrated row, so a value that was wrong at insert (pointing at a different, unrelated source entity's destination row, a 0/default, or a sibling/self fallback) otherwise stays wrong even though config_id_mappings holds the correct mapping. For every already-migrated trial_run row this re-reads the current source ids, translates them through the current config_id_mappings, and corrects whichever column(s) disagree.

jockey_id/trainer_id are discipline-aware (resolved via the trial's BDiscipline). course_id/runner_id accept any of a source id's mapped destinations (duplicate parents are not errors). A parent that was never migrated is left alone, never auto-copied. By default only trials dated on or after 2026-08-01 are touched (untick the box below for a full run).

• Trial Run → Course FK BCourseID → trial_run.course_id
• Trial Run → Runner FK BHorseID → trial_run.runner_id
• Trial Run → Jockey FK discipline-aware BJockeyID → trial_run.jockey_id
• Trial Run → Trainer FK discipline-aware BTrainerID → trial_run.trainer_id

Preview runs the exact same reads and resolves the exact same expected values, but skips the actual write — no column is changed. Use it to see what would change before committing to a real run.