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Posted by Rik on 08/18/06 21:09
Flaming Corncob wrote:
> In article <4kmaetFc7gcoU1@individual.net>,
> "J.O. Aho" <user@example.net> wrote:
>> Flaming Corncob wrote:
>>> In article <4km59fFcpnbrU1@individual.net>,
>>> "J.O. Aho" <user@example.net> wrote:
>>>
>>>> Flaming Corncob wrote:
>>>>> Ok, I just don't understand it.. what are the practical uses of
>>>>> indexes, AUTO_INCREMENT etc.. how are they supposed to work?
>>>> The sql server will take care of the increment of the value,
>>>> without you need
>>>> first check up whats the highest value, then add one to it and
>>>> then insert the
>>>> new data to the table. This can lead to that more than one will
>>>> try to insert
>>>> data with the same value, which leads to problems.
>>>> With the auto increment, you don't need to insert the value when
>>>> you insert
>>>> data into your table, it will automatically be inserted and
>>>> adjusted, and no
>>>> risk for two to get the same value.
>>>>
>>>> This is useful when you want to give unique id-numbers for all
>>>> rows in a table.
>>
>>> Sounds like what I already read.. just can't picture the practical
>>> use. Maybe because it's not what I'm looking for?
>>
>> I don't know what you are looking for, but AUTO_INCREMENT is really
>> useful for
>> row id's, if you don't use any row identification, then it's not
>> useful for you.
>
> I'm in the process of coding a forum. What I was looking for was
> something that keeps record of each folder/topic/subtopic/post, like
> an
> index number that is unique for each. When something is moved,
edited
> or deleted it would make it easy to "refer" to a number and in the
> case for example it is deleted anything under that referencing that
> number is
> also deleted, and the number could be re-used.
Reusing? Why? How many topics/posts do you expect? You'll have to be
very,very,very popular to run out of integers for a unique post. And
you shouldn't reuse them. For instance: some posts something, gets id
1234, and you can vies the post by viewpost.php?id=1234. It is some
usefull information, and some people link to it. Later on, the post is
deleted. No problem, in your code you take care of that: you inform
the user the post is no longer there. Would you reuse the number, the
link works again, and will show a post that has absolutely nothing to
do with the first post. People following the old links won't think
very highly of you forum.
Moral of the story: if possible, don't reuse unique identifiers.
> I thought indexes and
> such was the way to go, but I can't seem to make heads or tails
what's
> going on.
The right primary keys and indexed will enable your database to
perform queries a lot faster and efficient then they normally would.
Creating a unique id (primary key) will also have major advantages:
one simpel number to refer to, instead of searching on title/time/user
etc.
Grtz,
--
Rik Wasmus
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