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iterating through ResultSet

joew weakers
Ranch Hand

Joined: Aug 21, 2003
Posts: 48
Hi there. I am running a simple SQL query that returns a result set containing two columns. A sample set of results appears as follows:

D43 73
D43 78
D43 87
D44 65
D65 102
D65 107
D65 111
D65 115
D85 77
... ...

What I would like to do is for every distinct value encountered in the first column, create an object and set an array/vector of size equal to the number of values in the second column associated with that first column value. For example, an object called 'D43_object' that has a vector of size 3 containing the 3 ids associated with cfcc 'D43'. My attempt at coding this is as follows:

I know why my code does not work but I do not know how to go about altering it so that objects are instantiated correctly and how I can create new objects only for certain rows in the result set and not for every row in the result set. Can anybody show me how I might fix this. Thnaks a lot, Joe
Denise Hum

Joined: Oct 09, 2001
Posts: 20
Have you considered the idea of using a Hashtable with cfcc as the key and the vector of Ids as a value? This way you don't have to worry about the order of the the cfcc's being returned and I think you'd have to do less checking.
Jeanne Boyarsky
author & internet detective

Joined: May 26, 2003
Posts: 31826

Make sure you have an order by clause in your SQL statment so the cfcc's are returned in order.

The idea looks fine. Although "that has a vector of size 3 " is more of an implicit requirement. You will wind up with a Vector with three elements in it. But you don't need to know there are three before you start out.

The only thing I don't see is the collection you are storing all the LayerFeature objects in.

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joew weakers
Ranch Hand

Joined: Aug 21, 2003
Posts: 48
Hi Jeanne, Denise. Thanks a lot for your replies. Denise, I have not tried using Hsahtables just yet but I may use them in the future. Jeanne, I did as you suggested but I am still encountering the following error:

variable landmark_ids might not have been initialized

The code is as you specified:

Its kind of like the error I had initially. Have you any ideas. Cheers, joe
David O'Meara

Joined: Mar 06, 2001
Posts: 13459

Change this:

To this:

I agree. Here's the link:
subject: iterating through ResultSet