From: Peter Brawley
Date: September 27 2006 2:49pm
Subject: Re: Count of children
List-Archive: http://lists.mysql.com/mysql/202137
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André,

>I want the count of all sub-entries for a specific entry.

Depends on the model you are using--edge list or nested sets?

PB

-----

André Hänsel wrote:
> I have a table with id and parent_id.
> I want the count of all sub-entries for a specific entry.
>
> I found several documents about working with graphs/trees in MySQL but I
> could not find a solution for my problem.
>
> I can imagine two possibilities, but one is memory intensive and the other
> one creates load on updates.
> The first is, that I select all entries and then use a procedural language
> to determine recursively whether an node is a sub-node of the specific node.
> The second is, that I store the sub-node count with each node and when I do
> an insert, I walk the tree upwards and increment the node-counts.
>
> Is there a smart solution/best practice for my problem?
>
> Now I can't think of another sentence starting with an i. ;-)
>
> Best regards,
> André
>
>
>   


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