title: Axapta/DynamicsAx: UTC datetime conversion
body: <p>We are trying to interpret the data stored in Axapata's TIMEZONESRULESDATA table. Particularly, we'd like to figure out how it stores DST begin/end times. So far, my guess is:</p>
  
  <p>TZENUM: foreign key referencing TIMEZONESLIST (time zone name and identifier)<br>
  YEAR: 0 if rule is valid indefinitely or a year where the timezone rule is in effect<br>
  BIAS: offset to UTC time in minutes<br>
  DBIAS: offset of DST (added to BIAS to get total offset from UTC)  </p>
  
  <p>Now for the part I don't understand:  </p>
  
  <p>DYEAR,DMONTH,DDAYOFWEEK,DDAY,DHOUR,DMINUTE,DSECOND<br>
  SYEAR,SMONTH,SDAYOFWEEK,SDAY,SHOUR,SMINUTE,SSECOND  </p>
  
  <p>I would guess from the dates that the D* is the start date of DST and S* is end. However, I do not understand why it would need a year and a dayofweek field. Also, *DAY does not seem to indicate the day of month - at least it doesn't indicate the correct one for switching DST. It also doesn't seem to correspond to the dates at which Axapta's own DateTimeUtil or Form autoconversion converts the dates.</p>
  
  <p>Does anyone know how to interprete this table? Or where I could look it up?</p>
  
  <p>Sören</p>