How can we make H-Tree?

Question

can anyone guide me how can we make H-Tree and how can we call module by using H-Tree?
waiting for prompt answer.
thanks in advance
sarah
Edited by: user652484 on Aug 2, 2009 3:43 AM
Edited by: user652484 on Aug 2, 2009 3:45 AM

Answer 1

Dear,
Creating a Hierarchical Tree based on database table required a table with self-joined column like scott's emp table where column empno refered by mgr, a Data Query with PRIOR clause and a procedure call from the Form Level When-New-Form-Instance trigger.
There are many ways to make Hierarchical Tree. I am describing one of them bellow. Please follow the steps:
01. Create the following table
CREATE TABLE EMPLOYEE(
EMPLOYEE_ID NUMBER(4),
EMPLOYEE_NAME VARCHAR2(50),
MANAGER_ID NUMBER(4),
CONSTRAINT EMPLOYEE_PK PRIMARY KEY(EMPLOYEE_ID),
CONSTRAINT EMPLOYEE_FK FOREIGN KEY(MANAGER_ID)
REFERENCES EMPLOYEE(EMPLOYEE_ID)
02. Insert some data on it
03. Create a form module and name it HTREE_DEMO
04. Create a Data Block on this form and name it CONTROL.
05. Create a Hierarchical Tree Item on it and name it EMP_TREE. Hierarchical Tree must be single item on single block.
05. Write the following query on Data Query of the EMP_TREE Item
SELECT 1, LEVEL, EMPLOYEE_NAME, NULL, EMPLOYEE_ID
FROM EMPLOYEE
CONNECT BY PRIOR EMPLOYEE_ID = MANAGER_ID
START WITH MANAGER_ID IS NULL
06. Add the following line of code on the Form Level When-New-Form-Instance Trigger
FTREE.POPULATE_TREE('CONTROL.EMP_TREE);
07. Run the form
08. Enjoy!