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From Vinayak Borkar <vbo...@yahoo.com>
Subject Re: VXQuery Number Query Plans
Date Thu, 07 Jun 2012 02:54:49 GMT
> My questions:
>   - in 1. The plan use the function promote. Is this to ensure the type
> is correct for the addition function?
>   - in 1b. Why does the type here show anyAtomicType instead of integer?
>

The add function you use in the query is defined as an operator in the 
builtin-operators.xml file. Remember that this operator is polymorphic. 
It can add integers, doubles, duration to dates etc. So the static type 
of the operator's argument specify that they should be the supertype of 
all acceptable argument types and that is anyAtomicType in this case.

You are correct in that the promote will ensure that the input data is 
compliant with the expected argument type of the addition function.

At runtime, the function needs to make sure that the inputs are correct 
and throw a dynamic error otherwise.

Vinayak

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