Reduce Power BI Data Model Size Without Losing Information
Optimize model performance
Answer
Correct answer: D — Remove MovementDate to eliminate redundancy and reduce the data model size without losing information.
You import a Power BI dataset that contains the following tables: ✑ Date ✑ Product ✑ Product Inventory The Product Inventory table contains 25 million rows. A sample of the data is shown in the following table. [sampleXML/xmlfile-119_4.png] The Product Inventory table relates to the Date table by using the DateKey column. The Product Inventory table relates to the Product table by using the ProductKey column. You need to reduce the size of the data model without losing information. What should you do?
Community Insight
The core concept tested is data model optimization through column reduction, with the common trap being confusion between summarization settings and actual data storage volume.
This question addresses techniques to optimize a large Power BI data model by identifying and removing redundant columns. It establishes that removing duplicate or unnecessary columns is the most effective way to reduce storage size while preserving all unique data.
Many learners incorrectly choose Option A (Change Summarization for DateKey to Don't Summarize) because they misunderstand that changing aggregation behavior does not reduce the physical storage size of the underlying rows.
Community Discussion (88 comments)
MissElla
👍 1
Selected: D
B or D, as long as we have to chose only one answer, it would be D then
aa83599
👍 3
Selected: B
If you delete DATE table and Date Key, then you eliminate a lot of redundant data
jaume
👍 3
Selected: D
D. Remove MovementDate column as the data details are already included in the DateKey column therefore MovementDate information is redundant. By defaultI expect DateKey to be Don't Summarize but anyway, in the question it's not mentioned anything about Summarization. Removing relationship would make impossible to set any analysis based on date (you could split DateKey column and get from there day, month and year but this would increase data model size) Changing UnitCost to Integer (this category doesn't exist in PBI but Whole Number!!!) would result in lost of information as values in this column are all decimals
JPShields
👍 1
This requires you to notice that MovementDate and DateKey have the same date. I agree that it doesnt tell you they are ALWAYS the same though.
wistom
👍 4
If D is correct - how can we guarrantee that 'Movementdate' always has the same info as DateKey? i.e. having 5 identical rows does not tell us all rows are the same...
rcaliandro
👍 2
Selected: D
We can remove the movementdate 'cause the same information in kept in the datekey column
Mohamed_Nasr
👍 1
Selected: D
D is right one
Kiran37
👍 1
correct answer
shahrzadkhb
👍 1
Selected: D
D is correct. We can remove it since it does not provide new information. We can have these information from DateKey column.
MoneyStacking
👍 1
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Shark13
👍 1
Hey , out of 52 pages , how many pages you referred? Going through 52 pages is not feasible
ELJORDAN23
👍 1
Selected: D
D is correct.
0e18c76
👍 1
Yeah. There's a typo indeed. As per the explanation the response should be D.
AZFabio
👍 1
Selected: D
D is correct
Elektrolite
👍 1
You can also remove rows where nothing went in or out
GowthamMupparapu
👍 2
Selected: D
As per the given explanation option D is crearly the answer. We are achieving required functionality without losing information as both the rows contain same information
arrow040
👍 1
Selected: D
Dates can be removed from fact tables in a data warehouse or analytical database if you replace them with date keys that are linked to a separate date dimension table. Thus, answer D is correct.
Dani_eL
👍 1
Selected: D
wrong typing Correct Answer: A 🗳️ as explanation clearly states case D : "The DateKey and MovementDate columns have the same information. Movementdate can be removed."
Tsbki
👍 2
Selected: D
The view solutions pane says correct answer is A, but the explanation given clearly explain why D is the correct answer. ???
momo1165
👍 3
Movement date is correct, first because we do not know if the datekey is summarized or not in the first place. second if we have a date table that uses datekey then what do we need movement date for?
Dsbuff
👍 1
Selected: D
D is correct.
fbbucky
👍 2
Selected: D
definitely is D!
kimii1993
👍 10
Selected: D
- I said: D
KokS24
👍 4
All the questions that you got in the exam were from this website(without contributor access) only or from any other website. If yes please tell me your resources too.
Abir9564
👍 1
D should be correct answer according to my knowledge.
acvribeiro
👍 1
Selected: D
Remove unnecessary column
nick0651
👍 1
Selected: D
D is right
Rasaqh
👍 3
I think 'A' option will further increase the size of the model beacuse changing summarization to Don't Summarise will lead to the expansion of the data and thereby increasing the size. 'D' option, removing MovementDate will actually reduce the size of the data model.
Rasaqh
👍 3
What is the best way to reduce the size of the data model in Power BI? These techniques include: Remove unnecessary columns. Remove unnecessary rows. Group by and summarize. Optimize column data types. Preference for custom columns. Disable Power Query query load. Disable auto date/time. Switch to Mixed mode.
discoverp
👍 1
Selected: D
Correct answer = D Look at the explanation which exactly says why D is the right answer, not A.
Igetmyrole
👍 1
D is the answer. Although the reporting requirements determine what to choose, option D is correct among the options. Remove MovementDate is a valid option to reduce the size of the data model without losing information.
Anurekha
👍 1
Selected: D
D is correct answer
RicoPallazzo7
👍 1
Selected: D
The movement date can be retrieved from the dateKey. The A: why do change the summarization would lead to a reduced space?
Thubui
👍 1
they are of different types to mislead, to make us think they are different but they are just the same information. This question is a tricky one.
lmrod
👍 1
Different format doesn't imply different type. But I agree with you that "without losing information" should discard option D. We don't know if they use Movement Date in some way or if it's always equal to DateKey
CRAKN1
👍 1
Changing Summarization for DateKey to Don't Summarize might lead to incorrect results if you are using DateKey in relationships or calculations that require aggregation.
Cyprien_B
👍 1
Selected: D
Useless column
Regina18
👍 1
The DateKey column is a primary column, not a date column. therefore, they are different columns
Bnxyl
👍 5
Selected: A
The key statement is without losing information.
Maniula
👍 4
You don't loose any information with D. That date will still be in the model through DateKey & Date table.
Tofuuuu
👍 1
D RIGHT
LeeTheRed
👍 1
I meant no loss of information
Rinesh25
👍 1
Selected: A
Without losing data " A '' only correct
RicoPallazzo7
👍 1
you can retrieve the date from the dateKey field, i think it is D
lmrod
👍 2
Can we be sure that both tables contain the same data in the whole table?
Shalaleh
👍 1
Selected: D
We do not need Movement date column.
ApacheKafka
👍 1
But they are of different types. So ... A seems more logical.
wellingtonluis
👍 2
Attention to the subject "without losing information.", It can't be possible to be "D".
semauni
👍 8
DateKey and MovementDate contain the same data :)
LeeTheRed
👍 1
MovementDate has the same information as DateKey, so loss of information if removed.
RazaTheLegend
👍 1
Selected: D
See the given answer explanation, the answer from website is wrong but the arguement for D, which is correct Correct Answer : D No confusion, and no need to discuss further
SanaCanada
👍 1
Selected: D
You can also see the given answer explanation, they also with D but by mistake there is label A Correct Answer : D No confusion, and no need to discuss further
Aneran
👍 3
Selected: D
To reduce the size of the data model without losing information, you can consider removing the MovementDate column as option D suggests. The reason for this is that the MovementDate column might not be needed if it is already captured in the DateKey column. If the DateKey column includes information about the movement date of each inventory item, then the MovementDate column is redundant and can be removed.
ApacheKafka
👍 1
But cant you see they are of different types?
vysh07
👍 5
How we would be able to guess the ans if he didn't mention what he is analyzing? If he mentions we can understand what columns are needed for analysis and what is not required. Simply giving tables and saying remove the unnecessary columns and simply the model ho could we do. Can somebody help me ?
joaowendling
👍 3
In this case we can see that, whatever is being analyzed, the columns DateKey and MovementDate contain the same information. MovementDate can be removed since the relationship with the Date table is being made by the DateKey
srikanth923
👍 3
Selected: D
D is the answer, the movement date can be removed as the data key is still there
Champion1234
👍 1
Selected: D
D is correct
gilgir
👍 1
Ok, D is correct but I would have added a "group by" in "power query" SQL connection ...
AndM
👍 2
Selected: A
Why should D be correct? the sample does not say anything about the whole.
chezleon62
👍 2
D is correct
CluelessKamikaze
👍 1
Selected: D
D is correct. Movement Date is superfulous because we already have the Datekey column. Removing a column will reduce the data model size
MegaLion
👍 6
Selected: A
Because you need to reduce size of the model without losing any information
HoangNV
👍 1
I agree with you. Without losing any information is the most importance.
svg10gh
👍 1
Selected: D
D is right
kiwi69
👍 1
Selected: D
D is the right answer
LuukvdD
👍 2
Wouldn't you technically be able to reduce the size even more by creating two calculated columns: one to check if the unit price has changed compared to the previous record and one that adds the in and outgoing stock. Then you filter out the rows where there were no changes & where there was no stock movement, after which you delete both columns. It would make the refresh slower, but it would lead to a small dataset.
lsperes2982
👍 1
Selected: D
D is correct
Hoeishetmogelijk
👍 1
Selected: D
The DateKey and MovementDate columns have the same information. Movementdate can be removed.
Pauwels
👍 1
Selected: D
Correct Answer: A 🗳️ The DateKey and MovementDate columns have the same information. Movementdate can be removed. Incorrect: Not C: Integer data type would lose data.
musicalhacker
👍 2
Selected: A
Because You need to reduce the size of the data model without losing information.
mlehu
👍 2
Selected: D
D is the right answer
susunz
👍 2
Selected: D
D is right
dorypl300
👍 3
D, because the best way to reduce the data model size is to remove the unnecessary column.
samad1234
👍 2
D is correct
Mizaan
👍 4
Selected: D
Without doubt D. It does say without losing data, but it also says reduce size of the model. If you remove the movementdate, you still have that information in the date table
Popsyy
👍 2
Selected: D
D is right
NGenov
👍 1
It says "Without losing information". Nobody said datekey and movement date contain same information. A maybe could be correct.
lukelin08
👍 2
D The explanation is correct though
IxIsa
👍 3
Selected: D
D is correct
Manzy2599
👍 3
Selected: D
D is correct
Snow_28
👍 5
D is the right answer as it says to reduce the model size plus option A is not suitable because changing the summarize option to "Not summarize" will not affect the size of the model.
RichardOgoma
👍 5
Selected: D
The movement date field is not necessary since we can slice and dice with the date dimension table.
saurinkhamar
👍 3
D remove movementdate.
Manikom
👍 8
Selected: D
D is the correct
Jukibabu
👍 23
looks like a typo - D is good as explained below
ElijahSu
👍 59
Selected: D
D is right
Muffinshow
👍 6
Selected: D
D The explanation is correct though
Comments & Corrections
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Expert Analysis
Why the Answer Is Correct
Removing the MovementDate column (Option D) is the correct action because, as noted in community comments, it appears to be a duplicate of DateKey. In Power BI, each column consumes memory based on its cardinality and data type. If two columns contain identical information, one can be safely removed without losing any analytical capability or data integrity. This directly reduces the size of the dataset.Why the Other Options Are Wrong
Option A is incorrect because changing the summarization property affects how measures aggregate data in visuals but does not change the number of rows stored in the column. Options B and C are detrimental: removing relationships breaks data analysis capabilities, and changing UnitCost to Integer would likely result in loss of precision (information loss), violating the 'without losing information' constraint.Community Comment Notes
Community consensus strongly supports Option D. As user ElijahSu noted, "D is right." User semauni clarified the reasoning: "DateKey and MovementDate contain the same data:)". User Snow_28 added that "changing the summarize option... will not affect the size of the model," confirming why Option A is a distractor.Exam Strategy
Always look for redundancy in large tables before considering complex optimizations. If two columns seem to hold the same information, removing one is the fastest way to shrink the model size without affecting functionality.
Frequently Asked Questions
Why doesn't changing summarization reduce model size?
Summarization only changes how data aggregates in visuals; it does not remove rows from the table or reduce the storage footprint.
Is it safe to remove a column if it duplicates another?
Yes, if the columns contain identical values, removing one preserves all unique data and significantly reduces memory usage.
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