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Hey.. Arthur_Wood,<br />
<br />
Thanks for your input. It was accidentally posted by a friend using my account without me logging off first.<br />
As such, this question is closed now.<br />
<br />
Cheers<br />
hongjun
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Hey.. Arthur_Wood,

Thanks for your input. It was accidentally posted by a friend using my account without me logging off first.
As such, this question is closed now.

Cheers
hongjun

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Hi,<br />
<br />
&nbsp; &nbsp;I know that for weak entity, we have to include the primary keys of the strong attribute as one of the weak entity's attribute. I would like to know if it is possible that the primary keys of the weak entity does not include the primary key of the strong entity which it is related to? Lets say in one question, the answer given was <br />
<br />
<a href="https://www.experts-exchange.com/questions/10102690/Weak-and-Strong-Entities.html?query=weak+entity&clearTAFilter=true" rel="ugc">https://www.experts-exchange.com/questions/10102690/Weak-and-Strong-Entities.html?query=weak+entity&clearTAFilter=true</a><br />
<br />
Strong entity...<br />
Table Orders <br />
ID &nbsp; &nbsp; &nbsp; &nbsp;int &nbsp; &nbsp; &nbsp;Primary Key <br />
OrderNum &nbsp;varchar<br />
OrderDate datetime<br />
<br />
Table Items<br />
ID &nbsp; &nbsp; &nbsp; &nbsp;int &nbsp; &nbsp; &nbsp;Primary Key<br />
Desc &nbsp; &nbsp; &nbsp;varchar<br />
<br />
weak....<br />
Table OrderDetail<br />
OrderID &nbsp; int &nbsp; &nbsp; &nbsp;Foreign Key (references Order.ID)<br />
ItemID &nbsp; &nbsp;int &nbsp; &nbsp; &nbsp;Foreign Key (references Item.ID)<br />
Qty &nbsp; &nbsp; &nbsp; int <br />
<br />
So if I give a unique number lets say OrderDetail_id as the primary key, do I still need the OrderID and ItemID as one of the primary keys in the weak entity?
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Hi,

   I know that for weak entity, we have to include the primary keys of the strong attribute as one of the weak entity's attribute. I would like to know if it is possible that the primary keys of the weak entity does not include the primary key of the strong entity which it is related to? Lets say in one question, the answer given was 

http://www.experts-exchange.com/Databases/Q_10102690.html?query=weak+entity&clearTAFilter=true

Strong entity...
Table Orders 
ID        int      Primary Key 
OrderNum  varchar
OrderDate datetime

Table Items
ID        int      Primary Key
Desc      varchar

weak....
Table OrderDetail
OrderID   int      Foreign Key (references Order.ID)
ItemID    int      Foreign Key (references Item.ID)
Qty       int 

So if I give a unique number lets say OrderDetail_id as the primary key, do I still need the OrderID and ItemID as one of the primary keys in the weak entity?

weak entity and its primary key

Databases are organized collections of data, most commonly accessed through management systems including schemas, tables, queries and processes that allow users to enter and manipulate the information or utilize it in other fashions, such as with web applications or for reporting purposes.