I had to do this once... fun problem.
First of all, forget about doing it "in JSP"... you should use Java classes
for this.
Two ways to do it, IMO. If you have a large and flat dataset, i.e. many
records in the table but no trees that go more than a few generations deep,
you can have a method in the Person object of signature:
public Person[] getAllChildren()
that queries for all the children, and calls getAllChildren() on them, and
adds the results into some kind of vector. However, that will result in
many calls to the database because each getAllChildren() call will cost you
a query.
If the dataset is narrower and deeper, i.e. a few very deep families, you
can create a method that loads up all the data in one query and then
constructs the objects using a method similar to the above. The advantage
of this is that you only have to run the query once; the disadvantages are
that you have loaded all this data that may or may not be used.
Let me know if you need more detail...
-jmc
-----Original Message-----
From: Frank Mancini [mailto:[EMAIL PROTECTED]]
Sent: Monday, November 12, 2001 5:04 PM
To: [EMAIL PROTECTED]
Subject: Please help! Recursive loop in JSP
I have a recursive looping problem here.
For example, say I have this table
id, name, parent
1,john,4
2,bill,3
3,cathy,4
4,jackie,0
5,jeff,4
6,joe,7
7,amy,0
Essentially,
jackie doesn't have a parent, but has john, jeff and cathy as children. bill
is the child of cathy and thus jackies grandchild.
How would I do this query such that I say I want to see all the children
(including everyone below him/her) below, say jackie...this is really a self
join to oneself with an unknown number of levels below.
How would I do this in jsp do display all of jackies relatives below her?
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