[CentOS] Upgrade from 5.6 => 5.7
Emmanuel Noobadmin
centos.admin at gmail.com
Fri Sep 16 14:12:31 UTC 2011
On 9/16/11, Always Learning <centos at u61.u22.net> wrote:
> C1
>
> c1ref
> c1customer (code)
> c1quantity (integers only)
> c1price (in cents)
> c1discount (2 decimal places held as integers)
> c1catalogue (code)
> c1date (yymmdd)
> c1order (number)
> c1comments (text)
>
> then do a query:
>
> select c1quantity, c1price, c1discount from c1 where c1customer =
> 'joebloggs' and c1date like '10%'
Isn't it bad practise to store customer reference by name? What
happens if we want to look up a customer called John Smith and there
are say a dozen of them?
I would at the very least have a separate table holding core customer
information with an auto-incremented ID so that customers with the
same name won't cause a problem. Of course, that would mean requiring
a join on the query, or at the very least two queries with one pulling
the customer ID first. Although since the base customer ID table is
usually a frequently accessed but not changed table, it's likely to be
in memory and therefore faster to issue a join, which the dbms should
handle smartly enough than to separate queries.
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