小编MIS*_*ays的帖子

我检查了Oracle提供的文档,并找到了一种修改约束而不删除表的方法.问题是,它在修改时出错,因为它无法识别关键字.

使用EMS SQL Manager进行PostgreSQL.

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

我可以通过使用以下方法删除约束来解决它:

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", "order_id", "public_insurer_id")
    ON UPDATE CASCADE
    ON DELETE NO ACTION
    DEFERRABLE 
    INITIALLY DEFERRED;

我必须无法绕过试图在递归方法中存储值的概念.使用迭代解决这个问题需要几秒钟,但我正在努力进行递归调用.基本上我想解决:1/1 + 1/2 + 1/3 ......

 public static void main(String[] args) {

    Scanner input = new Scanner(System.in);    

    System.out.print("Enter in the end number for the sequence: ");
    int endpoint = input.nextInt();

    System.out.println("The value of the sequence is : " + calcSequence(endpoint));

    }

    public static double calcSequence (int index){

        if (index == 0)
            return 0;
        else
            return (1/index) + calcSequence(index - 1);
    }