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Benefits of having a Data Model before the presentation layer?

shyamcharan
Not applicable

Benefits of having a Data Model before the presentation layer?

Hi Experts,

I have worked on a qlikview design model where I have three different layers as mentioned before in all the QlikView solutions.

I have listed out the benefits as I can think. I appreciate if anyone add more to it.

QVD Layer(Extract Layer):

  1. This layer can be straight data dump from the DW
  2. The QVD Layer (which I tend to call the Extract layer) should be exactly the same as the data source. No transformation. Tracking back sums through each layer is easier.
  3. Matching the Extract with data source and Match the Model with the Extract is easy where a data issue may occur.

Data Model Layer:

  1. The difference is the Model is ready for a binary load to the UI / Dashboard where as a transform would create a new columns with all the calcs / renames / joins / mapping / etc.
  2. Most of the transformations can be done here reducing the effort on QVW layer
  3. Most of the complex calculations can be done here reducing the effort on the Chart/Tabular engines
  4. One Data Model can be used by multiple Dashboards hence reducing the effort in creating individual Data Models for different dashboards
  5. Benefit of the transform over a model is that multiple dashboards can mix and match and re-use the same QVD's (this is also the same as the extract layer, no point going to the same data source twice)
  6. Easy to maintain the changes. Requires less time in implementing the changes that effect multiple dashboards.
  7. When working in team or group scenarios, this type of division allows different layers of the application to be worked on simultaneously and independently of each other


Dashboard Layer:

  1. This is final presentation layer
  2. Better to push complex calculations to the Data Model Layer.
Comments
richard_pearce6
Not applicable

Totally agree!

richard_pearce6
Not applicable

My thoughts :

The QVD Layer (which I tend to call the Extract layer) should be exactly the same as the data source. No transformation. The reason being is that you can track back your sums through each layer. You would match your Extract with your data source. Match the Model with the Extract, etc. That way you can easily see where a data issue may occurring.

richard_pearce6
Not applicable

Cont.....

The next layer I would have as a transform (Model). The difference in my mind is the Model is ready for a binary load to the UI / Dashboard where as a transform would create a new set of QVD's with all the calcs / renames / joins / mapping / etc.

richard_pearce6
Not applicable

Cont.....

Benefit of the transform over a model is that multiple dashboards can mix and match and re-use the same QVD's (this is also the same as the extract layer, no point going to the same data source twice)

richard_pearce6
Not applicable

Sorry for all the posts. For some reason I was being blocked when trying to submit the whole thing....

Gabriel
Not applicable

Hi Richard,

I agree with both your points. Having Extraction layer without transformation is good and Transformation layer where you can create additional field(s) which include and not limited to calculation, derive new fields and many more is good idea.

Data trace-ability is possible and easy with this approach.

shyamcharan
Not applicable

Thank you all.

I have added your points to the list.

Regards,

Shyam

jaaldurgam
Not applicable

Good attempt. However there are some drawbacks of this approach. Now a days there is a bit fight happening between ETL and ELT approaches..

Good one!
Sreeni

Not applicable

Good One.. However, I also agree with Jd Sreeni's point

shyamcharan
Not applicable

Thanks for the Inputs sreeni.

Can you please provide more details so that I can add those to the above mentioned topic.

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Last update:
‎09-22-2015 11:24 PM
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