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Posted by Norman Peelman on 12/05/07 19:52
Mikhail Kovalev wrote:
> On 5 Des, 18:42, Norman Peelman <npeel...@cfl.rr.com> wrote:
>> Toby A Inkster wrote:
>>> Mikhail Kovalev wrote:
>>>> $array[112][COUNT] = 10;
>>>> $array[112][NEXT][225][COUNT] = 3;
>>>> $array[112][NEXT][225][NEXT][930][COUNT] = 1;
>>>> $array[112][NEXT][225][NEXT][930][NEXT] = array();
>>>> $array[112][NEXT][11][COUNT] = 5;
>>>> $array[112][NEXT][11][NEXT] = array();
>>>> An address is an array, f ex array(112, 225, 930)
>>> If $array[112][NEXT][11] exists, does that imply that
>>> $array[113][NEXT][11] cannot exist?
>>> i.e. Can 11 have only one "parent" or multiple?
>>> If it can only have one parent, then I'd suggest using the structure
>>> suggested by "C". If '11' can have more than one parent, then a classic
>>> tree structure is out of the window, so I'd suggest a simple string key,
>>> like this:
>>> CREATE TABLE nodes
>>> (
>>> node_address varchar(1024) NOT NULL PRIMARY KEY,
>>> node_count integer
>>> );
>>> To add counts to the database, you'd use:
>>> INSERT INTO nodes VALUES ('112', 10);
>>> INSERT INTO nodes VALUES ('112/225', 3);
>>> INSERT INTO nodes VALUES ('112/225/930', 1);
>>> INSERT INTO nodes VALUES ('112/11', 5);
>>> To retrieve the count for key array(112, 225, 930), you'd use:
>>> SELECT node_count
>>> FROM nodes
>>> WHERE node_address='112/225/930';
>>> To find a list of descendant nodes of '112', you'd use:
>>> SELECT node_address
>>> FROM nodes
>>> WHERE node_address LIKE '112/%';
>>> Or to find just child nodes (i.e. no grandchildren, etc):
>>> SELECT node_address
>>> FROM nodes
>>> WHERE node_address LIKE '112/%'
>>> AND NOT node_address LIKE '112/%/%';
>>> By the way -- do yourself a favour and stop naming your functions things
>>> like function_9() and function_10(), and variables like $array_3. If you
>>> have to come back to this code after 2 or 3 months away from it, you will
>>> have forgotten what they all do. Give them memorable names.
>> INSERT INTO nodes (node_address, node_count) VALUES ($node_address,
>> $node_count) ON DUPLICATE KEY UPDATE node_count=node_count+1
>>
>> ...will INSERT new entries and UPDATE existing entries in one swoop.
>>
>> Norm
>
> Ok, suppose I'm joining to structures which have been created
> separately,
> from before i have ('112/225/930', 3)
> and i want to add ('112/225/930', 2), which also happens to be present
> in the second table, only with a different count,
> to make ('112/225/930', 5)
>
> From there I want to make it the general case so that when updating an
> entry with count 1 I am actually adding ('112/225/930', 1) to the
> existing one, if it exists:
>
> INSERT INTO nodes (node_address, node_count) VALUES (<new_address>,
> <new_count>) ON DUPLICATE KEY UPDATE node_count = node_count +
> <new_count>
>
> Is this correct? (Do I have to use <> in VALUES, I'm following an
> example which does it?)
Ooops, in my other reply that should have read:
$your_variable = 2
"...ON DUPLICATE KEY UPDATE new_count = new_count + $your_variable"
....to add an arbitrary amount to new_count. 3 + 2 = 5 for your example.
Norm
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