Again, before I can answer that, I need to know how you want to conceptually handle the nesting. The "correct" way to put nested elements into a relational database would be to fold out additional lookup tables but that would get to be pretty complicated. The simplest (and "incorrect" i.e. non-relational) way is to serialize the data e.g. to join all of the nested fields into a single field with e.g. a semicolon separator. My guess is that your best option will be instead to "promote" the nested fields i.e. to go from this

  <PotentialSpecificHeat>
    <Bias>-4.43921585E-05</Bias>
    <Error1>0.53285588E-02</Error1>
    <Error2>0.57902443E-02</Error2>
    <Tau1>5.00000000E-01</Tau1>
    <Tau2>5.69579788E-01</Tau2>
    <Value>0.32688055</Value>
  </PotentialSpecificHeat>
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to this (eliminate PotentialSpecificHeat as an enclosing tag and promote its nested elements to unested tags with a PSH prefix to show their origin)

    <PSH_Bias>-4.43921585E-05</Bias>
    <PSH_Error1>0.53285588E-02</Error1>
    <PSH_Error2>0.57902443E-02</Error2>
    <PSH_Tau1>5.00000000E-01</Tau1>
    <PSH_Tau2>5.69579788E-01</Tau2>
    <PSH_Value>0.32688055</Value>
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If that kind of thing would work for you then you can use Perl to combine your files into one file and pre-process the nested tags into tags. You could then use DBD::AnyData on the results.