我想知道Hibernate内部是如何工作的。
所以,我在数据库里有一个叫“Peter”的人;
Session session = SessionFactory.openSession();
Person p = session.get(Person.class, 1);//Peter's id is 1
System.out.println(p.getName());//output : Peter
p.setName("Joey");
session.flush();
session.close();
现在这个人在数据库里的名字已经改成了"Joey“。
这是怎
我有一些密码:
CREATE OR REPLACE TEMPORARY VIEW cctv_join_1
AS
SELECT *
FROM cctv1_details AS A
LFET JOIN cctv3_details AS B ON (A.CDE_WR = B.CDE_WR) AND A.CDE_dist = B.CDE_dist
然后我试着
CREATE OR REPLACE TEMPORARY VIEW cctv_join_2
AS
(SELECT *
FROM cctv_join_1 AS A
LEFT JOIN cct
有人能告诉我在数据库里怎么做吗?
我尝试了一些sql,比如:
SELECT disastertype, YEAR(eventdate) as year,
COUNT(disastertype) AS disastertype_total
FROM v_disasterlogs_all
WHERE YEAR(eventdate) >= year(CURRENT_TIMESTAMP) - 4
GROUP BY YEAR(eventdate)
ORDER BY YEAR(eventdate) ASC
但是,它只显示了这样: