Composite Keys and Synthetic Keys

[lucarizziero]

Hello,

Hi have a data structure that create Synthetic keys based on key dimensions, but also other Synthetic keys based on other Synthetic key, causing slow performances (the biggest fact table has 50000 rows).

The last steps of script running highlights the situation:

I have my facts that refers to the product dimensions at different levels:

- cod_articolo & cod_articolo2

- cod_articolo & cod_articolo2 & cod_colore

- cod_articolo & cod_articolo2 & cod_colore & cod_fornitore

- cod_articolo & cod_articolo2 & cod_colore & cod_fornitore & taglia_num

Any suggestion ?

Thanks

[Miguel_Angel_Baeyens]

Hello Luca,

Since QlikView links tables using same named fields, it will create a synthetic key for each additional field named alike, solving all possible matches. They may be useful provided you want all those "joins" between your tables.

Say for example you have a fact table with Invoices, in which lines are stored not only the cod_articolo but the cod_articolo2 and cod_colore as well, and at the same time these fields can be retrieved from your main Articolo table, then you can not load them in the Invoice Line table, and only in the Articolo table. Besides, you can try to create by your own those composite keys, and use the AutoNumber() function on them, so QlikView will compare numbers, not alphanumerical values, and check if that performs better.

Hope that helps.