Total Inventory in database

Hello everyone and let me say thank you for the help. I'm developing
an inventory program using PHP and MySQL. So far I have the php
developed where you can enter a bar code, and type a quantity, and it
will log the serial and the quantity of that serial in the DB. What I
really want it to do is look to see if the bar code is already in the
database, and if so, then it simply adds the quantity that is being
input to the quantity value already in the DB. Presumably I also need
to subtract from the DB in a similar manner. Any ideas?
Thanks so much,
Brian

On 14 Apr, 14:34, Brian Spotts <neoca...@gmail.com> wrote:
> Hello everyone and let me say thank you for the help. I'm developing
> an inventory program using PHP and MySQL. So far I have the php
> developed where you can enter a bar code, and type a quantity, and it
> will log the serial and the quantity of that serial in the DB. What I
> really want it to do is look to see if the bar code is already in the
> database, and if so, then it simply adds the quantity that is being
> input to the quantity value already in the DB. Presumably I also need
> to subtract from the DB in a similar manner. Any ideas?
> Thanks so much,
> Brian

INSERT INTO ... SET..... ON DUPLICATE KEY UPDATE ....

excellent! Thanks for the quick response, but I'm relatively new to
mysql and php so is there any way you could elaborate on how to use
the command? I'm assuming its something like...
INSERT INTO ~tablename~ SET ~i'm not sure~ ON DUPLICATE KEY UPDATE
~quantity + "quant"~

I know that's not right, sorry I need more help but I'm happy to
realize that it seems to be an easy thing to do for people with more
experience. thanks so much.
-Brian

On 14 Apr, 15:25, Brian Spotts <neoca...@gmail.com> wrote:
> excellent! Thanks for the quick response, but I'm relatively new to
> mysql and php so is there any way you could elaborate on how to use
> the command? I'm assuming its something like...
> INSERT INTO ~tablename~ SET ~i'm not sure~ ON DUPLICATE KEY UPDATE
> ~quantity + "quant"~
>
> I know that's not right, sorry I need more help but I'm happy to
> realize that it seems to be an easy thing to do for people with more
> experience. thanks so much.
> -Brian

There's a phrase that goes with this. Its initials are RTFM

Even us "people with more experience" do this. Indeed, it is where we
manage to get our experience. It is said that "the Lord helps those
who help themselves". A similar thing applies here.

http://dev.mysql.com/doc/refman/5.0/en/insert.html