我已经检查了Oracle提供的文档，并找到了一种方法，而不会丢弃表。问题是，它在修改时出错，因为它不能识别关键字。
使用EMS sql Manager for Postgresql。

Alter table public.public_insurer_credit MODIFY CONSTRAINT public_insurer_credit_fk1
    deferrable,initially deferred;

我可以通过删除约束来解决它：

ALTER TABLE "public"."public_insurer_credit"
  DROP CONSTRAINT "public_insurer_credit_fk1" RESTRICT;

ALTER TABLE "public"."public_insurer_credit"
  ADD CONSTRAINT "public_insurer_credit_fk1" FOREIGN KEY ("branch_id","order_id","public_insurer_id")
    REFERENCES "public"."order_public_insurer"("branch_id","public_insurer_id")
    ON UPDATE CASCADE
    ON DELETE NO ACTION
    DEFERRABLE 
    INITIALLY DEFERRED;