MyDAC or VCL Bug ?

[swierzbicki]

Hi,

I just found that at runtime :

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If Query['MyDate'].IsNull then DoSomething();

get an EVariant Invalide OP error with message : Invalid variant operation
while

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If Query.FieldByName('MyDate').IsNull then DoSomething();

worked like a charm !

Is this a VCL bug or a MyDAC bug ?

Ps : MyDate is a TDateTimefield type

[Antaeus]

This is not a bug. These lines are not equal because this call

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  Query['MyDate']

returns value of Variant type, but this one

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  Query.FieldByName('MyDate')

returns value of TField type. TField has IsNull method implemented but Variant does not. Following three calls are equal:

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  Query['MyDate']
  Query.FieldValues['DName']
  Query.FieldByName('MyDate').Value

[swierzbicki]

Thank you for this explaination