diff --git a/prisma/migrations/20251107162000_prune_orphan_constructeur_links/migration.sql b/prisma/migrations/20251107162000_prune_orphan_constructeur_links/migration.sql
new file mode 100644
index 0000000..a73f945
--- /dev/null
+++ b/prisma/migrations/20251107162000_prune_orphan_constructeur_links/migration.sql
@@ -0,0 +1,14 @@
+-- Remove constructeur link rows that reference missing parents or constructeur records.
+-- This prevents foreign key violations when the orientation of the join tables is normalized.
+
+DELETE FROM "_MachineConstructeurs"
+WHERE "A" NOT IN (SELECT "id" FROM "machines")
+   OR "B" NOT IN (SELECT "id" FROM "constructeurs");
+
+DELETE FROM "_ComposantConstructeurs"
+WHERE "A" NOT IN (SELECT "id" FROM "composants")
+   OR "B" NOT IN (SELECT "id" FROM "constructeurs");
+
+DELETE FROM "_PieceConstructeurs"
+WHERE "A" NOT IN (SELECT "id" FROM "pieces")
+   OR "B" NOT IN (SELECT "id" FROM "constructeurs");