GO
BEGIN
IF (object_id('WMY', 'tr') is not null)
DROP trigger WMY
END;
GO
CREATE TRIGGER WMY
ON Student
Instead of INSERT
AS
BEGININSERT INTO Student (number,name) VALUES (1205,'角色2');
END;
--Begin 与end相当于{},是一个语句块,可有可无此处为演示所用
--ON 后面跟表明，表示作用于那个表
--ON Student下面(Instead of INSERT)可有改为(Instead of,after,for)(update,delete,Insert)

GO
INSERT INTO Student (number,name) VALUES (1807,'角色');

USE [OSMP]
BEGIN
IF EXISTS (SELECT * FROM sysobjects WHERE name = 'Person')
AND NOT EXISTS (select * from Person) --这条语句的意思是当表存在并且不为空是执行下面的语句 ，and对应&&，or 对应||
DROP table Person
END
GO
CREATE TABLE Person
(num int,S_score int,S_name NVARCHAR(64),primary key (num)
)
BEGIN
IF EXISTS (SELECT * FROM sysobjects WHERE name = 'Student')
AND NOT EXISTS (select * from Student)
DROP table Student
END
GO
CREATE TABLE Student
(score int,name NVARCHAR(64),primary key (name)
)
--创建序列
BEGIN
IF EXISTS (SELECT * FROM sysobjects WHERE name = 'Student_SEQ')
DROP SEQUENCE Student_SEQ
END
CREATE SEQUENCE Student_SEQ
MINVALUE 1
MAXVALUE 999999999999
START WITH 1
INCREMENT BY 1
CACHE 20;GO
BEGIN
IF (object_id('WMY', 'tr') is not null)
DROP trigger WMY
END;
GO
CREATE TRIGGER WMY
ON Student
instead of INSERT
AS
BEGIN

    Insert into Person (num,S_score,S_name)select next value for Student_SEQ,score,name from Inserted 

    --Insert into Person (num,S_score,S_name)select next value for Student_SEQ,a.* from Inserted a --简化写法    --Insert into Person select next value for Student_SEQ,* from Inserted

    --此处并无意思主要用于理解,执行下面的Student插入语句是，数据库维护了一个与Student数据结构一样的表Inserted,    --这里利用这个表和序列值来为Person做插入，而实际上没有执行Student插入，如果想要Student也执行把Instead of 改为for或after
END;
GO
Insert into Student(score,name) values('1','m');

GO
SELECT current_value FROM sys.sequences WHERE name = 'Student_SEQ'

DECLARE @index VARCHAR(20),@Orderindex VARCHAR(20);
select @index=next value for ENTITY_SEQ;
select @Orderindex= 'R_'+rtrim(ltrim(right(cast('00000000'+rtrim(cast(@index as int)) as varchar(20)),10)))

BEGINEXECUTE IMMEDIATE 'DROP TABLE Person';EXCEPTION WHEN OTHERS THEN NULL;
END;CREATE TABLE Person
(num        INTEGERS_score   INTEGER,S_name     NVARCHAR2(64),primary key (num)
)
BEGINEXECUTE IMMEDIATE 'DROP TABLE Student';EXCEPTION WHEN OTHERS THEN NULL;
END;CREATE TABLE Student
(score   INTEGER,name     NVARCHAR2(64),primary key (name)
)
--创建序列
BEGINEXECUTE IMMEDIATE 'DROP SEQUENCE Student_SEQ';EXCEPTION WHEN OTHERS THEN NULL;
END;
CREATE SEQUENCE Student_SEQ
MINVALUE 1
MAXVALUE 999999999999999999999999999
START WITH 1
INCREMENT BY 1
CACHE 20;

CREATE OR REPLACE TRIGGER TR_INST_DEVICE
BEFORE INSERT ON M_DEVICEENTITY
FOR EACH ROWBEGINselect Student_SEQ.NEXTVAL into :new.num from dual;--select 'A' || trim(to_char(:new.num, '00000000')) into :new.score from dual;--这个两语句作用并无练习，第一个取出序列的下一个值插入new表中(new表类似SQL server 中的Inserted)--更改score的标示发以A_0000001为样式，这个语句只做参考在此处无用也运行不了(因为表的字段类型）
END;

GO Insert into Student(score,name) values('1','m')

Insert into Person(n, num, name) select next value for ENTITY_SEQ,number,name from Student where number=114;
--next value for ENTITY_SEQ序列与select字段组合添加
Insert into Person(n, num, name) select cast(100 as int),number,name from Student where number=114;
--cast(100 as int)值与字段组合添加

 cmd.CommandText = @"SELECT * FROM (SELECT ROWNUM AS rowno, t.*  FROM  '+tablename +' tWHERE ROWNUM <=  '" + end + "') table_alias  WHERE table_alias.rowno >=  '" + start + "'";

   cmd.CommandText = @"select * from M_ORDERHANDLE where ORDERINDEX  = '" + orderindex + "'";

SELECT *FROM (SELECT ROWNUM AS rowno, t.*FROM emp tWHERE hire_date BETWEEN TO_DATE ('20060501', 'yyyymmdd')AND TO_DATE ('20060731', 'yyyymmdd')AND ROWNUM <= 20) table_aliasWHERE table_alias.rowno >= 10;

SELECT * FROM (SELECT * FROM M_ALARM ) WHERE ROWNUM <=500  ORDER BY ROWNUM Desc;

--Oracle环境下的时间比对语句
SELECT * FROM M_WORKORDER where CREATETIME  >= to_date('2015/03/23','yyyy-mm-dd hh24:mi:ss') and CREATETIME <= to_date('2016/03/23','yyyy-mm-dd hh24:mi:ss')SELECT * FROM M_WORKORDER where to_char(CREATETIME, 'yyyy-mm-dd hh24:mi:ss') >= '2015-03-01 00:00:00' and to_char(CREATETIME, 'yyyy-mm-dd hh24:mi:ss') <= '2016-04-05 00:00:00'
--注意时间格式转换为一致

//Oracle多表连接查询
string sql =  @"SELECT W.*, D.*, AH.*, A.ALARMDESCRIPTION, A.DETECTTIME, A.ALARMPHENOMENON, A.ENTITYTYPEFROM  M_WORKORDER W, M_ALARM A,(SELECT * FROM(SELECT ROW_NUMBER() OVER (PARTITION BY H.ALARMINDEX ORDER BY H.HANDLETIME DESC) N,H.* FROM M_ALARMHANDLE H)WHERE N = 1) AH,(SELECT * FROM M_CONFIGITEMRELATION C, M_BUSINESSENTITY B WHERE C.TARGETINDEX = B.ENTITYINDEX AND C.GROUPTYPE = 1) D WHERE W.ALARMINDEX = D.SOURCEINDEX(+) AND W.ALARMINDEX = AH.ALARMINDEX(+) ANDA.ALARMINDEX = W.ALARMINDEX AND to_char(CREATETIME, 'yyyy-mm-dd') >= '" + Convert.ToDateTime(StartTime).ToString("yyyy-MM-dd") + "' and to_char(CREATETIME, 'yyyy-mm-dd') <= '" + Convert.ToDateTime(EndTime).ToString("yyyy-MM-dd") + "' and rownum<20";

//SQL server 对应的多表连接查询
string sql = @"SELECT W.*, D.*, AH.*, A.ALARMDESCRIPTION, A.DETECTTIME, A.ALARMPHENOMENON, A.ENTITYTYPEFROM  M_ALARM A,M_WORKORDER W LEFT JOIN(SELECT * FROM (SELECT ROW_NUMBER() OVER (PARTITION BY H.ALARMINDEX ORDER BY H.HANDLETIME DESC) N,H.* FROM M_ALARMHANDLE H) MWHERE M.N=1)AH on W.ALARMINDEX = AH.ALARMINDEX  LEFT JOIN(SELECT * FROM M_CONFIGITEMRELATION C, M_BUSINESSENTITY B WHERE C.TARGETINDEX = B.ENTITYINDEX AND C.GROUPTYPE = 1)D ON W.ALARMINDEX = D.SOURCEINDEXWHERE A.ALARMINDEX = W.ALARMINDEX and CONVERT(varchar(100),w.createtime, 20) >= '" +   Convert.ToDateTime(StartTime).ToString("yyyy-MM-dd") + "' and   CONVERT(varchar(100),w.createtime, 20) <= '" + Convert.ToDateTime(EndTime).ToString("yyyy-MM-dd") + "'";