Hi
The correct way, IMHO, would be to consider the situation. The hard drives
are a sub component of the computer. In which case the hard drive table
should be a 'child' of the computer table.
However the hard drives could be an item in their own right too.
So if you want to consider the hard drive as an item, but to know which
computer it is in then make HardDriveID the primary key of the hard drive
table, and include ComputerID as a link field.
If it is basically a component of the computer then make
(ComputerID,HardDriveID) the primary key.
In practice either will work as will
Computer table
{
ComputerID(primary)
Hard_drive_1
Hard_drive_2
Hard_drive_3
......
Hard_drive_n
}
which is simpler, not good design, but probably OK if you are sure you will
never have more than 'n' drives
just my 2p worth
Peter
-----------------------------------------------
Excellence in internet and open source software
-----------------------------------------------
Sunmaia
www.sunmaia.net
[EMAIL PROTECTED]
tel. 0121-242-1473
-----------------------------------------------
> -----Original Message-----
> From: Mike Tuller [mailto:[EMAIL PROTECTED]]
> Sent: 23 June 2002 21:07
> To: Chris Barnes; Php-Db (E-mail)
> Subject: Re: [PHP-DB] Question
>
>
> That would probably work, but only for what I want right now. If I ever
> wanted to create a report of all the hard drives I have, it would become
> more difficult.
>
> I know I need to have a separate table in the database for the drives, but
> am not sure if the foreign key should be drives in the computer table, or
> computer in the drive table. I could just go ahead and work with it, but I
> am the type that wants to learn the right way in the beginning, not figure
> out later that I was doing it wrong. As far as normalization,
> In reply to
> Duncan's post) I have been reading up on that, and so far it
> hasn't given me
> the answer on this type of problem. Maybe what I am reading doesn't cover
> that, so if you are talking about a particular document, let me know and I
> will look at that.
>
> > From: "Chris Barnes" <[EMAIL PROTECTED]>
> > Date: Mon, 24 Jun 2002 05:03:53 +1000
> > To: "Php-Db \(E-mail\)" <[EMAIL PROTECTED]>
> > Subject: RE: [PHP-DB] Question
> >
> > i dont know how will this will work, but you could try storing
> the multiple
> > hard disk details for each computer in an "array" in 1 field.
> > then when you want to get the information from the db, use explode() to
> > store the value in the field into an array again.
> >
> > e.g.
> > the field in the DB might look like this...
> > HardDriveSize = "1.2Gb,25Gb,25Gb"
> >
> > so get the field from the db and then use explode() to store it
> in an array
> > in php.
> > e.g.
> > $disk_size = explode("," , $field);
> >
> > i dont know how well this will work for you...i'm only a newbie.
> >
> >
> > -----Original Message-----
> > From: Mike Tuller [mailto:[EMAIL PROTECTED]]
> > Sent: Monday, 24 June 2002 3:43 AM
> > To: [EMAIL PROTECTED]
> > Subject: [PHP-DB] Question
> >
> >
> > I am wanting to create a PHP frontend to a database that holds
> information
> > about the computers that I take care of. I have a problem though when it
> > comes to storing hard drive information. In most cases, the
> computers have
> > one drive, but some have 2 or more, so I can't create the main
> database with
> > fields like this.
> >
> > ComputerID
> > HardDriveType
> > HardDriveSize
> >
> > I know I will need to create a separate table to hold
> information about the
> > drives, and connect them to the computer by attaching the
> primary key of the
> > drives table to the Computer table.
> >
> > Computer Table
> >
> > ComputerID
> > DriveID
> > ------------------------
> > Drive Table
> >
> > DriveID
> > HardDriveType
> > HardDriveSize
> >
> > This is where I am unsure. If there is more than one drive,
> then this would
> > be incomplete because it would only show one drive. What is the
> best way to
> > make it so that all drives show for the computer, or am I doing this
> > backwards? Should I tie the computer to the drive instead?
> >
> > Thanks,
> > Mike
> >
> >
> > --
> > PHP Database Mailing List (http://www.php.net/)
> > To unsubscribe, visit: http://www.php.net/unsub.php
> >
> >
> > --
> > PHP Database Mailing List (http://www.php.net/)
> > To unsubscribe, visit: http://www.php.net/unsub.php
> >
>
>
> --
> PHP Database Mailing List (http://www.php.net/)
> To unsubscribe, visit: http://www.php.net/unsub.php
>
--
PHP Database Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
