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IntervalMatch, Slowly Changing Dimensions and Calendar

Hi everyone,


My  HR data model is made mainly with slowly changing dimensions, which I have combined into one 'Sub Intervals' table.

I have six tables of data HR dependent on the time that I had to control using the interval match and subintervlas.

Basically my end result is being able to choose a point in time in calendar, and see the state of my employees based on the different slowly changing dimensions.

Data model:

Unbenannt.PNG

I have two cases:

1. When I round up date(ceil(SubIntervalEnd)) in script I have problem with SubIntervals table, this table create one additional interval (31.12.2016 - 01.01.2017) which is wrong and if I didn't remove this row from table I have wrong result, when I choose last date in calendar.

Unbenannt.PNG

2. When I don't round up date(ceil(SubIntervalEnd)), IntervalMatch in BridgeTableKalendar I don't see last day with  connection to interval(01.01.2017).

Unbenannt.PNG

Do you know what is the problem? Where I made a mistake and how can I solve it?

SubIntervalBegin - min date is 01.01.2014

SubIntervalEnd   -  max date is 01.01.2017

Script:


Let vEpsilon = Pow(2,-27);

//// ============ Load all distinct beginnings and endings Intervals ============

TempSubIntervals:
//Tabelee PA0000
Load distinct PA0000.PERSONALNUMMER_TMP as PERSONALNUMMER, PA0000.BEGDA0001 as SubIntervalBegin  Resident PA0000;
Load distinct PA0000.PERSONALNUMMER_TMP as PERSONALNUMMER, PA0000.ENDDA0001 as SubIntervalBegin  Resident PA0000;
//Tabelle PA0001
Load distinct PA0001.PERSONALNUMMER_TMP as PERSONALNUMMER, PA0001.BEGDA0001 as SubIntervalBegin  Resident PA0001;
Load distinct PA0001.PERSONALNUMMER_TMP as PERSONALNUMMER, PA0001.ENDDA0001 as SubIntervalBegin  Resident PA0001;
... for rest table script looks the same


// ============ Create the SubIntervals ============

SubIntervals:
Load*,
PERSONALNUMMER & '|' & SubIntervalBegin  as SubIntervalID,
SubIntervalBegin & '-' & SubIntervalEnd as SubInterval.key;
Load
SubIntervalBegin  as SubIntervalBegin ,
date(ceil(SubIntervalEnd)) `      as SubIntervalEnd,
PERSONALNUMMER,
PERSONALNUMMER  as %PERSONALNUMMER.Personendaten,
Load PERSONALNUMMER
SubIntervalBegin,
Dual(SubIntervalEnd, (SubIntervalEnd - $(#vEpsilon))) as SubIntervalEnd
Where not IsNull(SubIntervalEnd) ;
Load PERSONALNUMMER, SubIntervalBegin,
If(PERSONALNUMMER = Previous(PERSONALNUMMER), Previous(SubIntervalBegin)) as SubIntervalEnd
Resident TempSubIntervals
Order By PERSONALNUMMER, SubIntervalBegin  Desc;
Drop Table TempSubIntervals;


TmpBridgeTablePA0000:
IntervalMatch (SubIntervalBegin, PERSONALNUMMER)
Load distinct PA0000.BEGDA0001PA0000.ENDDA0001, PA0000.PERSONALNUMMER_TMP as PERSONALNUMMER resident PA0000;

BridgeTable_PA0000:
Load
PERSONALNUMMER & '|' & SubIntervalBegin as SubIntervalID,
PERSONALNUMMER & '|' & PA0000.BEGDA0001 & '|' & PA0000.ENDDA0001 as PA0000.OriginalIntervalID
Resident TmpBridgeTablePA0000;


Drop table TmpBridgeTablePA0000;

TmpBridgeTablePA0001:
IntervalMatch (SubIntervalBegin, PERSONALNUMMER)
Load distinct PA0001.BEGDA0001PA0001.ENDDA0001, PA0001.PERSONALNUMMER_TMP as PERSONALNUMMER resident PA0001;

BridgeTable_PA0001:
Load

PERSONALNUMMER & '|' & SubIntervalBegin as SubIntervalID,
PERSONALNUMMER & '|' & PA0001.BEGDA0001 & '|' & PA0001.ENDDA0001 as PA0001.OriginalIntervalID
Resident TmpBridgeTablePA0001;

Drop table TmpBridgeTablePA0001;

... for rest table script looks the same

   TMP_Kalender:
LOAD
date(MinimumDatum + IterNo() - 1) as Datum,
date(MinimumDatum + IterNo() - 1) as %DATUM,
Month(date(MinimumDatum + IterNo() - 1)) as Monat,
Year( date(MinimumDatum + IterNo() - 1)) as Jahr,
Week( date(MinimumDatum + IterNo() - 1)) as Woche
WHILE MinimumDatum + IterNo() - 1 <= MaximumDatum;


LOAD
min(PA0000.BEGDA0001) as MinimumDatum,
   max(PA0000.ENDDA0001as MaximumDatum

RESIDENT PA0000;


NoConcatenate

Kalender:
LOAD
%DATUM,
// date(ceil(%DATUM)) as %DATUM,
Datum  as Kalender.Datum,
Monat  as  Kalender.Monat,
Jahr  as Kalender.Jahr,
MonthEnd(Datum) as Kalender.MonatJahr,
if(Datum = date(floor(MonthEnd(Datum))), floor(MonthEnd(Datum)),'') as Kalender.MonatJahrUltimo
Resident TMP_Kalender;

 

 

BridgeTableKalendar_TMP:
IntervalMatch (%DATUM)
Load Distinct SubIntervalBegin, SubIntervalEnd  Resident SubIntervals;


NoConcatenate


BridgeTableKalendar:
Load
(
SubIntervalBegin & '-' & SubIntervalEnd) as SubInterval.key,
SubIntervalBegin as TMPSubIntervalBegin,
SubIntervalEnd as TMPSubIntervalEnd,
%DATUM
Resident BridgeTableKalendar_TMP;

Drop table BridgeTableKalendar_TMP;

 

Thanks!

1 Solution

Accepted Solutions
MVP
MVP

Re: IntervalMatch, Slowly Changing Dimensions and Calendar

I think you are following pretty much the tech doc written by Henric

IntervalMatch and Slowly Changing Dimensions

but with slight modifications, which you should carefully review.

For example the original uses:

// ============ Create the bridge table between the two interval types ============

TmpBridgeTable:

IntervalMatch (SubIntervalEnd, SPID)

Load distinct OriginalBegin, OriginalEnd, TmpSPID as SPID resident OriginalIntervals;

BridgeTable:

Load

  SPID & '|' & SubIntervalEnd as SubIntervalID,

  SPID & '|' & OriginalBegin & '|' & OriginalEnd as OriginalIntervalID

  Resident TmpBridgeTable;

Drop Field TmpSPID;

Drop table TmpBridgeTable;



where you are using the SubIntervalBegin fields.

12 Replies

Re: IntervalMatch, Slowly Changing Dimensions and Calendar

I'm afraid I don't understand the issue. Do you have a date 01.01.2017 in your data? Is that supposed to be the last date in your data? And you want to be able to select that date? If so, then why shouldn't there be an interval 31.12.2016-01.01.2017?


talk is cheap, supply exceeds demand
MVP
MVP

Re: IntervalMatch, Slowly Changing Dimensions and Calendar

Magdalena, I think you are following Henric Cronstroem's tech doc about slowly changing dimensions, subchapter interval partioning.

There is a reason he is using

Dual(SubToDate, SubToDate - $(#vEpsilon)) as SubToDate

It creates a SubToDate showing the previously calculated SubToDate (which is effectively the start of the next subinterval for the same key), but having a numeric value just a little smaller / before.

This is to prevent that the Intervalmatch is making incorrect matches.

Looking at your data, if you remove the ceil() [which would recall the dual numeric part calculation shown above],

your interval match seem to correctly creating links for dates between 1.4.2016 and 31.12.2016 (including), while your PERSONALNUMMER seems to show exactely these BEGDA00001 and ENDDA00001 values for that interval.

Hence, I see no issue with removing the Ceil() function and just keeping to HIC's sample.

Or may I have missed something else?


Not applicable

Re: IntervalMatch, Slowly Changing Dimensions and Calendar

When I count(distinct PERSONALNUMMER) for 01.01.2017, it shows me wrong  data, becouse he counts  wrong row with interval 31.12.2016-01.01.2017.

Not applicable

Re: IntervalMatch, Slowly Changing Dimensions and Calendar

When I remove the ceil(), I have a problem with IntervalMatch calendar, because it does not refer to the date 01.01.2017 in the calendar intervals, when  ENDDA0001 is 01.01.2017, so the last day in Calendar(%DATUM) is 31.12.2016 for  ENDDA0001 (01.01.2017).

MVP
MVP

Re: IntervalMatch, Slowly Changing Dimensions and Calendar

It's hard to tell how to fix your issue without looking at your data.

I remember I had to adjust the interval creation in another thread

How to check whether certain record timestamps overlap...

Maybe check if the discussion there is giving you any hint, if not, try to create a small sample QVW that demonstrates your setting and issue, then upload this sample to this thread (you can use dummy data for this sample, but it should show your issue).

Not applicable

Re: IntervalMatch, Slowly Changing Dimensions and Calendar

Hi,

Sorry that's so late, in attached sample QVW.

BR,

Magda

MVP
MVP

Re: IntervalMatch, Slowly Changing Dimensions and Calendar

I am not 100% sure (well, it would be easier with a small, reloadable sample application), but maybe it's enough

to use ceil in your calendar bridge creation:

BridgeTableKalendar_TMP:

IntervalMatch (%DATUM)

Load Distinct SubIntervalBegin, Ceil(SubIntervalEnd) as SubIntervalEnd  Resident SubIntervals;

Not applicable

Re: IntervalMatch, Slowly Changing Dimensions and Calendar

I tried this but unfortunately this doesn't work properly.

MVP
MVP

Re: IntervalMatch, Slowly Changing Dimensions and Calendar

Could you check if attached model is correct?

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