Entity Relationships - Can a weak entity take part in a 'one to many' relationship as the 'one'

Posted by jonos on Stack Overflow See other posts from Stack Overflow or by jonos
Published on 2010-03-17T16:40:49Z Indexed on 2010/03/17 16:41 UTC
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relationship

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primary

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key

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cardinality

Hi,

With the following entity relationship structure I'm struggling to figure out if the relationship between the LOAN and ITEM is valid?

The weak entity of Loan uses a partial key of 'loan_dateLeant' and the primary keys from CUSTOMER and ITEM to form its primary key. However LOAN has a 'one to many' relationship with ITEM as a loan can consist of more than one item. But surely this means that if more than one item is loaned, then the loan record will have two item_id values for part of its primary key?

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