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This forum is provided to promote discussion amongst students enrolled in Data Warehousing (CITS3401).
 
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UWA week 17 - 1st semester, week 7

photo Re: use of fnlwgt (all 4)
Fri 24th Apr, 12:18pm, Edward A.
ANONYMOUS wrote: Can you please link that previous post, I have either answered or read the answer to this question at least twice now and don't ever recall that being said. Final weight is not a count of the number of people that row represents. This is...

UWA week 16 - 1st semester, mid-semester break

photo Re: Dimension (all 3)
Sun 19th Apr, 3:15pm, Edward A.
If you have defined concept hierarchies you should already be able to do that. Ensure that your hierarchies are defined in Visual Studio and then import your data into Power BI using a live connection and you should be able to drill down and roll up your...
photo Re: DWT Resources (all 5)
Thu 16th Apr, 5:08pm, Edward A.  O.P.
Yes, I wrote this question and then tried to do the regeneration by hand and realised very quickly what they are used for. Incidentally if anyone else was interested in a more CS based and practical demonstration of how this works I found this thesis...
photo Re: DWT Resources (all 5)
Thu 16th Apr, 4:13pm, Edward A.  O.P.
Thanks for the resource Zeyi. I appreciate this is a very large, but also very useful field. In the example given in the lecture, would I be wrong in thinking that only the first two values of the vector produced by DWT (sqrt(2), -sqrt(2)) would be required...
photo DWT Resources (all 5)
Wed 15th Apr, 8:54pm, Edward A.
Hi Zeyi, Do you have any more resources on DWTs? I've reviewed the lecture slides and read the textbook and have a high level understanding of how DWTs work but I was looking for an example that can link the high level concept with the low-level calculations...
photo Re: Data cleaning (all 3)
Mon 13th Apr, 9:29pm, Edward A.
Personally I did a little data cleaning to fix a couple of niggling issues and to add a column for one of my concept hierarchies. I didn't remove the ?? rows because I figured there may be interesting patterns among groups that had unknown values for...
photo Re: Paste diagrams (both)
Mon 13th Apr, 9:26pm, Edward A.
Insert -> Image on Power BI
photo Re: fnlwgt meaning (all 7)
Mon 13th Apr, 9:25pm, Edward A.
Really depends upon your business queries. I think the whole point of this assignment is that we run through the process of designing a data warehouse, developing our approach based on what questions we want to answer. I realise that sounds like a bit...
photo Re: Can't see hierarchies when data is imported but fine when a live connection is used (all 4)
Mon 13th Apr, 5:32pm, Edward A.  O.P.
To answer my second question: Power BI can't import hierarchies locally, though you can build local hierarchies (which you can't do if you connect live). These hierarchies are stored alongside your Power BI file and are not reflected in your data cube....
photo Re: fnlwgt meaning (all 7)
Mon 13th Apr, 5:30pm, Edward A.
I assume so, I'm just answering questions if I know the answer because I know how frustrating this project is when you just need a small question answered
photo Re: fnlwgt meaning (all 7)
Mon 13th Apr, 4:43pm, Edward A.
It means final weight. This data set is intended to be used for testing out neural nets trying to predict the income bracket of people based on the various attributes in the data set. There is no reason to keep it for this analysis.
photo Re: Can't see hierarchies when data is imported but fine when a live connection is used (all 4)
Mon 13th Apr, 4:22pm, Edward A.  O.P.
Another question if anyone knows the answer. Why is it possible to take averages of facts when data is imported, but not when a live connection is used? Is this because when the data is imported Power BI can manipulate it in memory whereas a live connection...
photo Can't see hierarchies when data is imported but fine when a live connection is used (all 4)
Mon 13th Apr, 4:18pm, Edward A.
I've put together my data cube in Visual studio and am using the data in Power BI. In Visual studio I've created two hierarchies for my dimensions, but when I import the data into Power BI the hierarchies aren't included (even though I explicitly selected...

UWA week 15 - 1st semester, non-teaching week

photo Re: Visio (all 4)
Sat 11th Apr, 3:03pm, Edward A.
I personally used draw.io, which in my opinion is the least painful of the free drawing software available online (also available across platforms [including linux] as an offline app). There's no template or particular shapes used to create starnets,...
photo Re: Some questions: (all 3)
Fri 10th Apr, 4:34pm, Edward A.
1. In one of the lab sessions I believe Tom said that a business query does not have to have a complete query footprint, meaning that if your query does not concern some of your dimensions at all your footprint won't be a complete loop of the starnet....
photo Assignment Part 1: Starnet footprint for query on facts?
Wed 8th Apr, 4:58pm, Edward A.
I am using the US Income data set and have stored age and capital gains as facts in my fact table. One of my business queries is "Do younger people have lower capital gains than older people?". However, given this structure neither capital gains nor age...
photo Assignment Part 1: Code for data wrangling (both)
Wed 8th Apr, 4:41pm, Edward A.
In order to load the data into our database for the first part of the assignment are we allowed to write programs to manipulate the data? If so, would you like us to submit them with our assignment?

UWA week 13 - 1st semester, week 5

photo Re: Lecture 4: 60,000 possible dimension table rows (all 3)
Sun 29th Mar, 11:44am, Edward A.  O.P.
To answer my own question in the hope it might help someone else. The 60,000 unique values for each dimension limitation is a product of the fact that a 2 byte key is used to index rows in the dimension tables. This means that 2^16 - 1 rows can be stored,...
photo Re: Analysis Services Not Showing Up in SSMS (all 4)
Wed 25th Mar, 4:08pm, Edward A.  O.P.
ANONYMOUS wrote: I did manage to fix this problem by following the document supplied with lab 4. However, I have run into another problem getting VS to process my database, some kind of problem with impersonation.
photo Lecture 4: 60,000 possible dimension table rows (all 3)
Tue 24th Mar, 9:57pm, Edward A.
Hi Zeyi , I was just wondering how you calculated that each dimension table in scenario C for the example you ran through in lecture 4 would have 60,000 possible rows? Wouldn't it be possible for a dimension to have 100 million unique values if there are...
photo Re: Integration Service Project (all 4)
Mon 23rd Mar, 9:19pm, Edward A.
ANONYMOUS wrote: How?
photo Analysis Services Not Showing Up in SSMS (all 4)
Mon 23rd Mar, 9:19pm, Edward A.
I've got up to the step in week 4's lab where we are using SSMS to find the name of our Analysis Services server. I have completed all the steps in Option-Doc-VS-Extensions document and verified that all the necessary extensions are installed. I have...
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