On Dec 26, 2011, at 1:57 AM, Amit Tandon wrote:
Dear Karl
Foreign key is a good option (provided you use InnoDB database) to
automate
the deletion/updation of cart details when you remove cart.
Besides 1:1 cardinality is good or bad can only be decided on the
semantics
of your tables.
As a an aside, if it is 1:1 cardinality, then you can probably merge
the
two tables
============
regds
amit
"The difference between fiction and reality? Fiction has to make
sense."
On Mon, Dec 26, 2011 at 12:38 PM, Karl DeSaulniers <karl@xxxxxxxxxxxxxxx
>wrote:
Hello all,
I have two database tables. Cart and a cartdetails.
I want the information for the cartdetails to be based on/
autofilled info
from cart.
I want the ability to delete from cart and cartdetails to
automatically
clear as well.
Would a foreign key be best suited for this? What kind of cardnaility
would I use 1:1 ?
Hope I make sense.
Hope everyone had a great holidays!
Best,
Karl DeSaulniers
Design Drumm
http://designdrumm.com
Thanks Amit for the reply.
Ok, so if you can not merge the two tables, then it is not a 1:1
relationship?
EG:
(table)CART:
cartID - PRIMARY
username
firstname
lastname
product
long description
quantity
options
price
(table)CARTDETAILS:
cartdetailsID
cartID - Foreign Key (Unique)
product
short description (taken from long des. in CART)
quantity
options
price
Is this a 1:1 if the key is between the two cartID's?
What is actually happening when I make a foreign key?
What does the foreign key cover? Just the row its linked to or the
whole table?
For this structure I would like, in order for their to be cartdetails,
there should be a cart.
If there is a cart then a cartdetails needs to automatically/
progmatically generate.
(I think I read somewhere that MySQL is capable of doing this before
sending back responses. Please correct me if I am wrong or if its
unrelated.)
What kind of relation is that?
Also, if you or someone could explain what these cardinality rules
mean. What..
0 or 1 does?
1+ does?
0,1+ does?
Many (kind-of figured this one out, perhaps not.)
etc..
I think that would help me greatly. I hope I am not sounding like a
help vamp.
I only ask because my google foo has failed me on where to search for
these specific answers.
Links are appreciated. I like to do stuff on my own but sometimes the
brain cramps. :)
TIA
Best,
Karl DeSaulniers
Design Drumm
http://designdrumm.com
