函数分为(1)系统函数,(2)自定义函数,我来为大家科普一下关于数据库里面的表触发器存储过程?以下内容希望对你有帮助!

数据库里面的表触发器存储过程(函数-存储过程-触发器)

数据库里面的表触发器存储过程

一、函数

函数分为(1)系统函数,(2)自定义函数。

其中自定义函数又可以分为(1)标量值函数(返回单个值),(2)表值函数(返回查询结果)

本文主要介绍自定义函数的使用。

(1)编写一个函数求该银行的金额总和

create function GetSumCardMoney() returns money as begin declare @AllMOney money select @AllMOney = (select SUM(CardMoney) from BankCard) return @AllMOney end

函数调用

select dbo.GetSumCardMoney()

上述函数没有参数,下面介绍有参数的函数的定义及使用

(2)传入账户编号,返回账户真实姓名

create function GetNameById(@AccountId int) returns varchar(20) as begin declare @RealName varchar(20) select @RealName = (select RealName from AccountInfo where AccountId = @AccountId) return @RealName end

函数调用

print dbo.GetNameById(2)

(3)传递开始时间和结束时间,返回交易记录(存钱取钱),交易记录中包含 真实姓名,卡号,存钱金额,取钱金额,交易时间。

方案一(逻辑复杂,函数内容除了返回结果的sql语句还有其他内容,例如定义变量等):

create function GetExchangeByTime(@StartTime varchar(30),@EndTime varchar(30)) returns @ExchangeTable table ( RealName varchar(30), --真实姓名 CardNo varchar(30), --卡号 MoneyInBank money, --存钱金额 MoneyOutBank money, --取钱金额 ExchangeTime smalldatetime --交易时间 ) as begin insert into @ExchangeTable select AccountInfo.RealName,CardExchange.CardNo,CardExchange.MoneyInBank, CardExchange.MoneyOutBank,CardExchange.ExchangeTime from CardExchange left join BankCard on CardExchange.CardNo = BankCard.CardNo left join AccountInfo on BankCard.AccountId = AccountInfo.AccountId where CardExchange.ExchangeTime between @StartTime ' 00:00:00' and @EndTime ' 23:59:59' return end

函数调用

select * from GetExchangeByTime('2018-6-1','2018-7-1')

方案二(逻辑简单,函数内容直接是一条sql查询语句):

create function GetExchangeByTime(@StartTime varchar(30),@EndTime varchar(30)) returns table as return select AccountInfo.RealName,CardExchange.CardNo,CardExchange.MoneyInBank, CardExchange.MoneyOutBank,CardExchange.ExchangeTime from CardExchange left join BankCard on CardExchange.CardNo = BankCard.CardNo left join AccountInfo on BankCard.AccountId = AccountInfo.AccountId where CardExchange.ExchangeTime between @StartTime ' 00:00:00' and @EndTime ' 23:59:59' go

函数调用:

select * from GetExchangeByTime('2018-6-19','2018-6-19')

(4)查询银行卡信息,将银行卡状态1,2,3,4分别转换为汉字“正常,挂失,冻结,注销”,根据银行卡余额显示银行卡等级 30万以下为“普通用户”,30万及以上为"VIP用户",分别显示卡号,身份证,姓名,余额,用户等级,银行卡状态。

方案一:直接在sql语句中使用case when

select * from AccountInfo select * from BankCard select CardNo 卡号,AccountCode 身份证,RealName 姓名,CardMoney 余额, case when CardMoney < 300000 then '普通用户' else 'VIP用户' end 用户等级, case when CardState = 1 then '正常' when CardState = 2 then '挂失' when CardState = 3 then '冻结' when CardState = 4 then '注销' else '异常' end 卡状态 from BankCard inner join AccountInfo on BankCard.AccountId = AccountInfo.AccountId

方案二:将等级和状态用函数实现

create function GetGradeByMoney(@myMoney int) returns varchar(10) as begin declare @result varchar(10) if @myMoney < 3000 set @result = '普通用户' else set @result = 'VIP用户' return @result end go create function GetStatusByNumber(@myNum int) returns varchar(10) as begin declare @result varchar(10) if @myNum = 1 set @result = '正常' else if @myNum = 2 set @result = '挂失' else if @myNum = 3 set @result = '冻结' else if @myNum = 4 set @result = '注销' else set @result = '异常' return @result end go

函数调用实现查询功能

select CardNo 卡号,AccountCode 身份证,RealName 姓名,CardMoney 余额, dbo.GetGradeByMoney(CardMoney) 账户等级,dbo.GetStatusByNumber(CardState) 卡状态 from BankCard inner join AccountInfo on BankCard.AccountId = AccountInfo.AccountId

(5)编写函数,根据出生日期求年龄,年龄求实岁,例如:

生日为2000-5-5,当前为2018-5-4,年龄为17岁​ 生日为2000-5-5,当前为2018-5-6,年龄为18岁

测试数据如下:

create table Emp ( EmpId int primary key identity(1,2), --自动编号 empName varchar(20), --姓名 empSex varchar(4), --性别 empBirth smalldatetime --生日 ) insert into Emp(empName,empSex,empBirth) values('刘备','男','2008-5-8') insert into Emp(empName,empSex,empBirth) values('关羽','男','1998-10-10') insert into Emp(empName,empSex,empBirth) values('张飞','男','1999-7-5') insert into Emp(empName,empSex,empBirth) values('赵云','男','2003-12-12') insert into Emp(empName,empSex,empBirth) values('马超','男','2003-1-5') insert into Emp(empName,empSex,empBirth) values('黄忠','男','1988-8-4') insert into Emp(empName,empSex,empBirth) values('魏延','男','1998-5-2') insert into Emp(empName,empSex,empBirth) values('简雍','男','1992-2-20') insert into Emp(empName,empSex,empBirth) values('诸葛亮','男','1993-3-1') insert into Emp(empName,empSex,empBirth) values('徐庶','男','1994-8-5')

函数定义:

create function GetAgeByBirth(@birth smalldatetime) returns int as begin declare @age int set @age = year(getdate()) - year(@birth) if month(getdate()) < month(@birth) set @age = @age - 1 if month(getdate()) = month(@birth) and day(getdate()) < day(@birth) set @age = @age -1 return @age end

函数调用实现查询

select *,dbo.GetAgeByBirth(empBirth) 年龄 from Emp

二、触发器

触发器分类:(1) “Instead of”触发器(2)“After”触发器“Instead of”触发器:在执行操作之前被执行“After”触发器:在执行操作之后被执行

触发器中后面的案例中需要用到的表及测试数据如下:

--部门 create table Department ( DepartmentId varchar(10) primary key , --主键,自动增长 DepartmentName nvarchar(50), --部门名称 ) --人员信息 create table People ( PeopleId int primary key identity(1,1), --主键,自动增长 DepartmentId varchar(10), --部门编号,外键,与部门表关联 PeopleName nvarchar(20), --人员姓名 PeopleSex nvarchar(2), --人员性别 PeoplePhone nvarchar(20), --电话,联系方式 ) insert into Department(DepartmentId,DepartmentName) values('001','总经办') insert into Department(DepartmentId,DepartmentName) values('002','市场部') insert into Department(DepartmentId,DepartmentName) values('003','人事部') insert into Department(DepartmentId,DepartmentName) values('004','财务部') insert into Department(DepartmentId,DepartmentName) values('005','软件部') insert into People(DepartmentId,PeopleName,PeopleSex,PeoplePhone) values('001','刘备','男','13558785478') insert into People(DepartmentId,PeopleName,PeopleSex,PeoplePhone) values('001','关羽','男','13558788785') insert into People(DepartmentId,PeopleName,PeopleSex,PeoplePhone) values('002','张飞','男','13698547125')

(1)假设有部门表和员工表,在添加员工的时候,该员工的部门编号如果在部门表中找不到,则自动添加部门信息,部门名称为"新部门"。

编写触发器:

create trigger tri_InsertPeople on People after insert as if not exists(select * from Department where DepartmentId = (select DepartmentId from inserted)) insert into Department(DepartmentId,DepartmentName) values((select DepartmentId from inserted),'新部门') go

测试触发器:

insert People(DepartmentId,PeopleName,PeopleSex,PeoplePhone) values('009','赵云','男','13854587456')

我们会发现,当插入赵云这个员工的时候会自动向部门表中添加数据。

(2)触发器实现,删除一个部门的时候将部门下所有员工全部删除。

编写触发器:

create trigger tri_DeleteDept on Department after delete as delete from People where People.DepartmentId = (select DepartmentId from deleted) go

测试触发器:

delete Department where DepartmentId = '001'

我们会发现当我们删除此部门的时候,同时会删除该部门下的所有员工

(3)创建一个触发器,删除一个部门的时候判断该部门下是否有员工,有则不删除,没有则删除。

编写触发器:

drop trigger tri_DeleteDept --删除掉之前的触发器,因为当前触发器也叫这个名字 create trigger tri_DeleteDept on Department Instead of delete as if not exists(select * from People where DepartmentId = (select DepartmentId from deleted)) begin delete from Department where DepartmentId = (select DepartmentId from deleted) end go

测试触发器:

delete Department where DepartmentId = '001' delete Department where DepartmentId = '002' delete Department where DepartmentId = '003'

我们会发现,当部门下没有员工的部门信息可以成功删除,而部门下有员工的部门并没有被删除。

(4)修改一个部门编号之后,将该部门下所有员工的部门编号同步进行修改

编写触发器:

create trigger tri_UpdateDept on Department after update as update People set DepartmentId = (select DepartmentId from inserted) where DepartmentId = (select DepartmentId from deleted) go

测试触发器:

update Department set DepartmentId = 'zjb001' where DepartmentId='001'

我们会发现不但部门信息表中的部门编号进行了修改,员工信息表中部门编号为001的信息也被一起修改了。

三、存储过程

存储过程(Procedure)是SQL语句和流程控制语句的预编译集合。

(1)没有输入参数,没有输出参数的存储过程。

定义存储过程实现查询出账户余额最低的银行卡账户信息,显示银行卡号,姓名,账户余额

--方案一 create proc proc_MinMoneyCard as select top 1 CardNo 银行卡号,RealName 姓名,CardMoney 余额 from BankCard inner join AccountInfo on BankCard.AccountId = AccountInfo.AccountId order by CardMoney asc go --方案二:(余额最低,有多个人则显示结果是多个) create proc proc_MinMoneyCard as select CardNo 银行卡号,RealName 姓名,CardMoney 余额 from BankCard inner join AccountInfo on BankCard.AccountId = AccountInfo.AccountId where CardMoney=(select MIN(CardMoney) from BankCard) go

执行存储过程:

exec proc_MinMoneyCard

(2)有输入参数,没有输出参数的存储过程

模拟银行卡存钱操作,传入银行卡号,存钱金额,实现存钱操作

create proc proc_CunQian @CardNo varchar(30), @MoneyInBank money as update BankCard set CardMoney = CardMoney @MoneyInBank where CardNo = @CardNo insert into CardExchange(CardNo,MoneyInBank,MoneyOutBank,ExchangeTime) values(@CardNo,@MoneyInBank,0,GETDATE()) --go

执行存储过程:

exec proc_CunQian '6225125478544587',3000

(3)有输入参数,没有输出参数,但是有返回值的存储过程(返回值必须整数)。

模拟银行卡取钱操作,传入银行卡号,取钱金额,实现取钱操作,取钱成功,返回1,取钱失败返回-1

create proc proc_QuQian @CardNo varchar(30), @MoneyOutBank money as update BankCard set CardMoney = CardMoney - @MoneyOutBank where CardNo = @CardNo if @@ERROR <> 0 return -1 insert into CardExchange(CardNo,MoneyInBank,MoneyOutBank,ExchangeTime) values(@CardNo,0,@MoneyOutBank,GETDATE()) return 1 go

执行存储过程:

declare @returnValue int exec @returnValue = proc_QuQian '662018092100000002',1000000 print @returnValue

(4)有输入参数,有输出参数的存储过程

查询出某时间段的银行存取款信息以及存款总金额,取款总金额,传入开始时间,结束时间,显示存取款交易信息的同时,返回存款总金额,取款总金额。

create proc proc_SelectExchange @startTime varchar(20), --开始时间 @endTime varchar(20), --结束时间 @SumIn money output, --存款总金额 @SumOut money output --取款总金额 as select @SumIn = (select SUM(MoneyInBank) from CardExchange where ExchangeTime between @startTime ' 00:00:00' and @endTime ' 23:59:59') select @SumOut = (select SUM(MoneyOutBank) from CardExchange where ExchangeTime between @startTime ' 00:00:00' and @endTime ' 23:59:59') select * from CardExchange where ExchangeTime between @startTime ' 00:00:00' and @endTime ' 23:59:59' go

执行存储过程:

declare @SumIn money --存款总金额 declare @SumOut money --取款总金额 exec proc_SelectExchange '2018-1-1','2018-12-31',@SumIn output,@SumOut output select @SumIn select @SumOut

(5)具有同时输入输出参数的存储过程

密码升级,传入用户名和密码,如果用户名密码正确,并且密码长度<8,自动升级成8位密码

--有输入输出参数(密码作为输入参数也作为输出参数) --密码升级,传入用户名和密码,如果用户名密码正确,并且密码长度<8,自动升级成8位密码 select FLOOR(RAND()*10) --0-9之间随机数 create proc procPwdUpgrade @cardno nvarchar(20), @pwd nvarchar(20) output as if not exists(select * from BankCard where CardNo=@cardno and CardPwd=@pwd) set @pwd = '' else begin if len(@pwd) < 8 begin declare @len int = 8- len(@pwd) declare @i int = 1 while @i <= @len begin set @pwd = @pwd cast(FLOOR(RAND()*10) as varchar(1)) set @i = @i 1 end update BankCard set CardPwd = @pwd where CardNo=@cardno end end go declare @pwd nvarchar(20) = '123456' exec procPwdUpgrade '6225547854125656',@pwd output select @pwd

作者:農碼一生,

原文链接:https://www.cnblogs.com/wml-it/p/16105503.html

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