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Hi there:
My client has provided me with some tables in order to create a Dashboard; if I load them into Qlik without further transformation I get this:
How bad is this? Cause according to official documentation:
Multiple synthetic keys are often a symptom of an incorrect data model, but not necessarily. However, a sure sign of an incorrect data model is if you have synthetic keys based on other synthetic keys.
I have read here and here that, indeed, there's no need to worry about synthetic keys themselves, but I do have several synthetic combinations ($Syn5 to $Syn8) that seem to be a sure sign of an incorrect data model.
I realize there are some redundancies; for instance, ID_MES is included within FCH_ACTO_COMERCIAL (even ID_ANIO goes within ID_MES, but at least ID_ANIO only appears in one table, TABLA_FCH_DIA, and doesn't mess with connections between tables):
ID_ANIO | ID_MES | FCH_ACTO_COMERCIAL |
2020 | 202001 | 20200101 |
Anyway, I have tried some test graphics and they work pretty fine:
Can't say the same when I try to optimize the data model with my own keys:
Hash256(ID_SFID, ID_MES, FCH_ACTO_COMERCIAL) as %key1
Hash256(ID_MES, ID_SFID, LINEA_NEGOCIO_NMR) as %key2
Synthetics go away and it looks much nicer, but some of my graphs stop working properly:
For instance, now it seems it's unable to relate TABLA_TRAFICO (where NUM_TRAFICO_BRUTO belongs to) to TABLA_SFID (where DE_NOMBRE_MANAGER_KAM and DE_ENSENIA belong to), and no idea what happens to the forth widget, that disappears completely (all of their fields belong to the same table, ACTIVIDAD_PPALES_LOB).
Well, thanks in advance for your help.