Question

我创建了两个表deposit和final_balance;我想在deposit_amount表中求deposit并将结果插入final_balance表。我可以使用触发器吗？

CREATE TABLE deposit(cust_id VARCHAR2(10),loan_id VARCHAR2(10),deposit_type VARCHAR2(10),deposit_amount NUMBER(20));
INSERT INTO deposit values ('001CUS1','001LOAN1','Fixed',3500);
INSERT INTO deposit values ('001CUS2','001LOAN2','Fixed',3900);
INSERT INTO deposit values ('001CUS3','001LOAN3','Fixed',7000);
INSERT INTO deposit values ('001CUS4','001LOAN4','Fixed',28000);
INSERT INTO deposit values ('001CUS5','001LOAN5','Fixed',15200);
INSERT INTO deposit values ('001CUS6','001LOAN6','Fixed',2420);
INSERT INTO deposit values ('001CUS7','001LOAN7','Primary',2420);
INSERT INTO deposit values ('002CUS1','002LOAN1','Primary',27000);
INSERT INTO deposit values ('002CUS2','002LOAN2','Primary',20200);
INSERT INTO deposit values ('002CUS3','002LOAN3','Primary',6900);
CREATE TABLE final_balance(
total_deposit NUMBER(20)
);

Answer 1

如果您需要一次性评估，可以使用：

SQL> insert into final_balance
  2    select sum(deposit_amount)
  3    from deposit;

1 row created.

如果您需要自我更新结果，视图将是更好的解决方案：

SQL> CREATE VIEW v_final_balance(total_deposit) as
  2  select sum(deposit_amount)
  3    from deposit;

View created.

一开始，它们都显示相同的结果：

SQL> select * from final_balance;

TOTAL_DEPOSIT
-------------
       116540

SQL> select * from v_final_balance;

TOTAL_DEPOSIT
-------------
       116540

更新deposit表格中的数据后，视图将显示更新的总金额，而无需触发器：

SQL> INSERT INTO deposit
  2       VALUES (
  3               'XX',
  4               'YY',
  5               'ZZ',
  6               1000000000
  7              );

1 row created.

SQL> select * from final_balance;

TOTAL_DEPOSIT
-------------
       116540

SQL> select * from v_final_balance;

TOTAL_DEPOSIT
-------------
   1000116540

您甚至可以使用基于触发器的方法，但它需要插入，更新，删除的触发器，从而产生更复杂的解决方案。如果您对触发器没有特定需求，我相信该视图是最佳解决方案。

计算列值并插入另一个表

1 个答案: