Hierarchial Loop II | Database Journal

Hierarchial Loop II

Mar 30, 2009
1 minute read




>>Script Language and Platform: Oracle
This script displays all of the employees in SCOTT.EMP table, with all of the bosses they report to, in a hierarchial loop, along with their level in the hierarchy.


Author: JP Vijaykumar



The business wants all of the employees in SCOTT.EMP table be displayed, with all of the bosses they report to, in a hierarchial loop, along with their level in the hierarchy. For this, I created a function to display the desired results.

create or replace function hierarchial_loop_jp(v_emp in number)
return varchar2 as
/*****************************************************
Author JP Vijaykumar, Oracle DBA,
Date  Sep 30th 2007
This function takes one argument empno
*****************************************************/
v_out varchar2(3000);
begin
for c1 in (select empno, level from scott.emp
    connect by prior mgr = empno start with empno = v_emp) loop
if (v_out IS NULL) then
v_out:=c1.level||’:’||c1.empno;
else
v_out:=v_out||’::’||c1.level||’:’||c1.empno;
end if;
end loop;
return v_out;
end;
select hierarchial_loop_jp(empno) from scott.emp;
HIERARCHIAL_LOOP3_JP(EMPNO)
———————————————————————–
1:7369::2:7902::3:7566::4:7839
1:7499::2:7698::3:7839
1:7521::2:7698::3:7839
1:7566::2:7839
1:7654::2:7698::3:7839
1:7698::2:7839
1:7782::2:7839
1:7788::2:7566::3:7839
1:7839
1:7844::2:7698::3:7839
1:7876::2:7788::3:7566::4:7839
1:7900::2:7698::3:7839
1:7902::2:7566::3:7839
1:7934::2:7782::3:7839

The business wants the level to be displayed in the reverse order, which means the level of KING should always be 1.

create or replace function hierarchial_loop_jp(v_emp in number)
return varchar2 as
/*****************************************************
Author JP Vijaykumar, Oracle DBA,
Date  Sep 30th 2007
This function takes one argument empno
*****************************************************/
v_out varchar2(3000);
v_lvl number;
begin
select max(level) into v_lvl from scott.emp
       connect by prior mgr = empno start with empno = v_emp;
for c1 in (select empno from scott.emp
           connect by prior mgr = empno start with empno = v_emp) loop
if (v_out IS NULL) then
v_out:=v_lvl||’:’||c1.empno;
else
v_out:=v_out||’::’||v_lvl||’:’||c1.empno;
end if;
v_lvl:=v_lvl – 1;
end loop;
return v_out;
end;
select hierarchial_loop_jp(empno) from scott.emp;
HIERARCHIAL_LOOP3_JP(EMPNO)
———————————————————————–
4:7369::3:7902::2:7566::1:7839
3:7499::2:7698::1:7839
3:7521::2:7698::1:7839
2:7566::1:7839
3:7654::2:7698::1:7839
2:7698::1:7839
2:7782::1:7839
3:7788::2:7566::1:7839
1:7839
3:7844::2:7698::1:7839
4:7876::3:7788::2:7566::1:7839
3:7900::2:7698::1:7839
3:7902::2:7566::1:7839
3:7934::2:7782::1:7839
14 rows selected.


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