CREATE TABLE "A" (
  "id" int PRIMARY KEY,
  "b_id" int
);

CREATE TABLE "B" (
  "id" int PRIMARY KEY,
  "a_id" int
);

ALTER TABLE "A" ADD FOREIGN KEY ("b_id") REFERENCES "B" ("id") DEFERRABLE INITIALLY IMMEDIATE;

ALTER TABLE "B" ADD FOREIGN KEY ("a_id") REFERENCES "A" ("id") DEFERRABLE INITIALLY IMMEDIATE;

