Importing non duplicate records from a XML file to a SQL server with LINQ

I have a SQL server database with th开发者_运维百科e following structure:

[Order]
OrderId
CustomerId
(...)

[OrderDetail]
OrderDetailId
OrderId
ProductId
Quantity 
(....)

I want to import an xml file like this that can contain records already inserted in the database:

<import>
    <orders>
        <order Id="1" />
        <order Id="2" />
        <order Id="3" />
    </order>
    <orderDetails>
        <orderDetail id="1" orderId="1" product="123" quantity="1" />
        <orderDetail id="2" orderId="1" product="456" quantity="5" />
    </orderDetails>
</import>

What is the most optimal way to read the xml file with LINQ2XML and check the database and insert only the non duplicate (new) rows to the database using LINQ2SQL?

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Since both of these tables have ID columns, you could just surround the insertion method with a try/catch and trap any PK exceptions. Sounds fairly efficient to me.