B Chase Mon Oct 11 02:06:42 -0400 2010

Subject: Associations

This is a great resource! However, I can't get my head around "associations". Can someone explain them in greater and more elementary detail? And/or link to an understandable online tutorial (I've looked and haven't found). I just cant' understand what it means for the "main record" to be associated with other records?????

Thanks.


Jono B Mon Oct 11 10:28:44 -0400 2010

Table customer
id
name
address
etc...

Table order
id
customer_id
order_date
etc...

Each customer can have many orders. The relation (or association) is the primary key from custmer table (id) and the foreign key from order table (customer_id)

Have a look at something like http://en.wikipedia.org/wiki/Database_normalization and http://en.wikipedia.org/wiki/Relational_model. Its a bit heavy in some places, but this should give you an idea of associations (or relations)

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