DataType - the “type class” of the tag, used to tell which column the data comes from.
0 - Int
1 - Float
2 - String
3 - Date/Time
QueryMode - another name for “interpolation” mode, or the “category” of data.
0 - Discrete/Digital
3 - Analog
How’d it go from 0 to 3? 1 used to be analog, but with 7.3 we had to change what analog meant (with compression), so 1=Old style analog, while 3=new compressed analog. 2 means the same as 1, but as a selectable option, which isn’t actually selectable right now (it was used for testing/dev, but we didn’t think it made sense in the release).
For what it’s worth, I’ll throw in a bonus note about what the different analog modes mean:
1 or 2, old style - simple deadband. With 2 values stored, the system only interpolates from V2.timestamp-SC_Exec_Rate.
3, new style - SLIM compression. With 2 values, the system interpolates across the full range from V1.timstamp->V2.timestamp.
The repercussions for this are that graphing the raw data looks more correct with the new system, but discrete values incorrectly classified look worse.
Ok, way more than you asked for.