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Triggers / procedures help

开发者 https://www.devze.com 2023-01-26 03:24 出处:网络
create tablestudent (spnrVARCHAR(5)PRIMARY KEY, s开发者_运维技巧nameVARCHAR(10), saddressVARCHAR(10),
create table  student
(spnr   VARCHAR(5)  PRIMARY KEY,
s开发者_运维技巧name   VARCHAR(10),
saddress    VARCHAR(10),
stel    VARCHAR(10) )

create table course
    (ccode  VARCHAR(5)  PRIMARY KEY,
    cname   VARCHAR(10),
    caddress    VARCHAR(10),
    points  int )

create table studies
    (id     int     PRIMARY KEY,
     spnr   VARCHAR(5)  NOT NULL,
     ccode  VARCHAR(5)  NOT NULL,
     result int,    
    CONSTRAINT STUDIES_SPNR_FK FOREIGN KEY(spnr) REFERENCES student(spnr),
    CONSTRAINT STUDIES_CCODE_FK FOREIGN KEY(ccode) REFERENCES course(ccode) )

create trigger t1  on  course
after update,insert
as
    print 'inside trigger';
    select i.ccode from inserted i, deleted d
    where i. ccode = d. ccode

create procedure what (@tableName varchar(10))
as 
begin

    declare @name varchar(20);

    declare c cursor for 
    select column_name 
    from information_schema.columns
    where table_name = @tableName;
    open c;
    fetch c into @name;
    while @@fetch_status = 0 begin
        print 'name:' + @name;
        fetch c into @name;
    end

    close c;
    deallocate c;
end;

When running:

begin transaction
insert into course values('K1','data1','lund',5);
update course
set cname ='informatik';
commit

The following message is displayed:

   inside trigger

(0 row(s) affected)

(1 row(s) affected)
inside trigger

(1 row(s) affected)

(1 row(s) affected)

In the end, why does 1 row affected show 2 times in the end?? When it only changes cname to "informatic" at one position?


One "1 row affected" results from the UPDATE and one from the SELECT within the trigger. Try removing the SELECT from the trigger and you should only see one "1 row affected."

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