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BACKEND CONCEPTS
Lecture No. 10
Thursday, September 21, 2000
“Backend programming”
CIS 560: Database System Concepts
Kansas State University
Department of Computing and Information Sciences
BACKEND CONCEPTS
CONTENTS
• Stored procedures
• Functions
• Triggers
• Reports
• Assignment 3
CIS 560: Database System Concepts
Kansas State University
Department of Computing and Information Sciences
BACKEND CONCEPTS
Stored procedure
create or replace procedure SAMPLE_PROC
(ssn_val IN number, sal_val IN number)
AS
BEGIN
insert into salary values (ssn_val, sal_val);
END;
show errors;
CIS 560: Database System Concepts
Kansas State University
Department of Computing and Information Sciences
BACKEND CONCEPTS
Functions
create function SAMPLE_FUNC (ssn_val IN number)
RETURN NUMBER
IS
sal_val NUMBER;
BEGIN
select salary INTO sal_val from SALARY
where ssn = ssn_val;
RETURN (sal_val);
EXCEPTION
WHEN NO_DATA_FOUND THEN
RAISE_APPLICATION_ERROR (-20100, ’ERROR');
END;
CIS 560: Database System Concepts
Kansas State University
Department of Computing and Information Sciences
BACKEND CONCEPTS
Triggers
• Row level triggers
• Statement level triggers
• Before and after triggers
• Instead of triggers
CIS 560: Database System Concepts
Kansas State University
Department of Computing and Information Sciences
BACKEND CONCEPTS
Triggers
• create trigger SAMPLE_TRIG
before update on SALARY
for each row
when (new.salary < old.salary)
begin
insert into SALARY_LOWERED values (old.ssn);
end;
• alter trigger sample_trig enable;
• alter table salary enable all triggers;
CIS 560: Database System Concepts
Kansas State University
Department of Computing and Information Sciences
BACKEND CONCEPTS
Reports
rem Printing a report
ttitle 'Salary values'
btitle 'Report generated by Arul'
column ssn heading 'Social|Security|number'
rem column ssn format a12
column ssn truncated
column salary heading 'salary'
rem column salary format a20
set linesize 40
set pagesize 20
spool report.lst
select * from salary;
spool off
CIS 560: Database System Concepts
Kansas State University
Department of Computing and Information Sciences
BACKEND CONCEPTS
Assignment 3...
CIS 560: Database System Concepts
Kansas State University
Department of Computing and Information Sciences