Microsoft Power BI exam 70-778 preparation workshop

martinraffeiner.com │ m_raffeiner
22.06.2019
Preparing for "Analyzing and Visualizing Data with Power BI (Microsoft Exam 70-778)”

Preparing for "Analyzing and Visualizing Data with Power BI (Microsoft Exam 70-778)” martinraffeiner.com │ m_raffeiner
martinraffeiner.com │martin@martinraffeiner.com │ m_raffeiner

This workshop...
Managing expectations
IS…
• Interactive
• Hands-on
• Meant to be a guide
• An overview of important concepts (and functionalities)
• …hopefully fun with some light bulb moments for you!
IS NOT…
• Providing exam questions
• A replacement for self-preparation
• A detail training (in M, DAX,…)
• A walkthrough of every functionality

It‘s also possible to do a 3-day bootcamp...
Managing expectations

It is important to grasp the main concepts.
The „Big Picture“
Power BI Desktop
„Consuming and transforming
data by using Power BI Desktop“
Queries
„Modeling and visualizing data“
Data
Reports
Power BI Service
„Configure dashboards, reports,
and apps in the Power BI
Service“
Datasets
Workspaces
Apps
Reports
Dashboards
…
Power BI Mobile App
„Query“ „Publish“

Let‘s get started.
Consuming and transforming data by using Power BI Desktop
Power BI Desktop
data by using Power BI
Desktop“
Queries
Data
Model
Reports
Power BI Service
Service“
Datasets
Workspaces
Apps
Reports
Dashboards
…
Power BI Mobile App

You can connect to databases, files and folders with different connectivity
modes.
Data sources Data connectivity modes
• Import
• Direct Query
• Live Connection
Model size, Data refresh, Performance, Data
transformation, Data modeling, Security,…
https://radacad.com/directquery-live-connection-or-import-data-tough-decision
→ Composite models!

It used to be like that...
Pictures from a presentation held by Kasper de Jonge

Then...composite models

And now...

Let‘s get some data
Hands-on

Let‘s talk about some Power Query essentials.
Power Query Editor
• Formula Bar (Advanced Editor!)
• Query Settings pane
• Data preview (Caching!)
• Query Dependencies
• …
Data types
Power Query: Data Model:

Let‘s look at the anatomy of a Power Query („M“) function.
let
Source = Csv.Document(…)
#"Promoted Headers" = Table.PromoteHeaders(Source, [PromoteAllScalars=true]),
#"Changed Type" = Table.TransformColumnTypes(#"Promoted Headers",{{"SalesTerritoryKey", Int64.Type},
{"SalesTerritoryRegion", type text}, {"SalesTerritoryCountry", type text}, {"SalesTerritoryGroup", type text}})
in
#"Changed Type"
https://docs.microsoft.com/en-us/powerquery-m/understanding-power-query-m-functions
https://docs.microsoft.com/en-us/powerquery-m/power-query-m-reference

Let‘s clean and transform some data.
Hands-on
Some keywords
• Query folding
• Duplicate/ reference queries
• Enable load
• Several ways to one goal (e.g. error handling,
conditional column vs. column from example,…
• Functions and Parameters
• …
https://www.biinsight.com/power-bi-desktop-query-parameters-part-1/
https://www.biinsight.com/power-bi-desktop-query-parameters-part2-dynamic-data-masking-
and-query-parameters/
https://www.biinsight.com/power-bi-desktop-query-parameters-part-3-list-output/
https://radacad.com/custom-functions-made-easy-in-power-bi-desktop

Let‘s move on.
Modeling and visualizing data
Power BI Desktop
Queries
Data
Model
Reports
Power BI Service
Service“
Datasets
Workspaces
Apps
Reports
Dashboards
…
Power BI Mobile App

First things first: some theory.
The „Model“ window Some keywords
• Fact/ Dimension, Lookup/ Measure, Source/ Target
tables
• Active/ Inactive relationship
• Cardinality
• (Cross-) Filter direction

Let‘s look at model ambiguity.
Pictures from https://www.sqlbi.com/articles/bidirectional-relationships-and-ambiguity-in-dax/

Let‘s calculate some columns and explore report features.
Hands-on
Some keywords
• Sort by column
• Create categories
• Create hierarchy
• Navigate hierarchy

Let‘s look at some DAX functions.
Aggregation functions e.g.:
• SUM
• AVERAGE
Iteration functions e.g.:
• SUMX
• AVERAGEX
https://docs.microsoft.com/en-us/dax/dax-function-reference
Filter functions e.g.:
• CALCULATE
• CROSSFILTER
Time-intelligence functions e.g.:
• PREVIOUSYEAR
• …
And more…
Date and time functions e.g.:
• MONTH, DAY,…
• TODAY
Text functions e.g.:
• CONCATENATE
• FORMAT

Let‘s do some DAX.
Understanding „Filter context“ Some keywords
• Every cell is an island
• „Filter context“ and „Row context“ both are
evaluation contexts
• CALCULATE
• ..and more!
Picture from https://www.excelguru.ca/blog/

Let‘s visualize some data using a gauge.
From here… To here…( and e.g. showing only data for YEAR 2014)
• Sales Amount
• Sales Territory Plan

Let‘s visualize some data using a stacked column chart.
From here… To here…( and e.g. showing only data for YEAR 2014)
• Sales Amount
• Product Category
• Year

Some more keywords.
(What) Do you know about…
• Row Level Security
• Interactions (between visuals)
• Phone Layout
• Custom visuals
• Performance Analyzer
• Themes
• Q&A
• AI
• Incremental Refresh
• Aggregations
https://community.powerbi.com/t5/Themes-Gallery/bd-p/ThemesGallery

Let‘s move on.
Configure dashboards, reports, and apps in the Power BI Service
Power BI Desktop
Queries
Data
Model
Reports
Power BI Service
Service“
Datasets
Workspaces
Apps
Reports
Dashboards
…
Power BI Mobile App

Let‘s look at two of the most important topics here.
Understanding data refresh (8 vs. 24 times) Sharing/ Collaborating
Picture from https://docs.microsoft.com/en-us/power-bi/refresh-data
Types of data refresh
Picture from
https://static1.squarespace.com/static/52d1b75de4b0ed895b7e7de9/t/5cfc076387c
0cc000168d8e8/1560020840670/BestPracticesForDeliveringAndSharingContentInPo
werBI_MelissaCoates.pdf

Some more keywords.
(What) Do you know about…
• Dashboards
• Alerts
• Analyze in .xls
• Data Gateway
• Power BI API
• Embedding Power BI
• ….

The exam itself.
Microsoft Exam 70-778
Microsoft Exam 70-778: https://www.microsoft.com/en-us/learning/exam-70-778.aspx
Types of exam questions: https://www.microsoft.com/en-us/learning/certification-exams.aspx?types=true

5 personal tips.
Microsoft Exam 70-778
1. Relax, you are prepared! It’s maybe just the same thing as it was for me: Your last exam has been quite some time
ago. So just actively accept the upcoming tension and let it go again.
2. Don’t make the mistake to search in the internet for exam questions. There will be always a question you might not
be able to answer. Beside that, you do not even know if the provided answers are correct.
3. Expect long questions. There is a lot of information. Read through each question line by line. Filter which information
is relevant. Use paper and pencil to write down the main points. Also drawing sometimes helps. Especially when it
comes to data modelling questions.
4. Don’t panic if you do not know an answer immediately. Maybe you want to revisit the respective question at the very
end of the exam.
5. Plan your time wisely. Divide the number of questions by the time given. Like this, you can roughly estimate how
much time you can spend for one question. This also prevents you from overthinking a question.
https://www.martinraffeiner.blog/preparing-for-analyzing-and-visualizing-data-with-power-bi-microsoft-exam-70-778-part-2/

Besides the links directly included in the presentation, some other resources which I
can highly recommend for your exam preparation.
Resources
General/ Overarching:
• Exam preparation playlist from “Guy in a Cube”: https://www.youtube.com/playlist?list=PLv2BtOtLblH1dQPV49Ni12olDcUoW-GEl
Loading and transforming data:
• Pivot and Unpivot with Power BI: https://radacad.com/pivot-and-unpivot-with-power-bi
• Data Privacy Settings: https://blog.crossjoin.co.uk/2017/05/24/data-privacy-settings-in-power-bipower-query-part-1-performance-implications/ (there
are several parts)
• Power Query site by Ken Puls and Miguel Escobar with lots of useful articles and resources (Free eBook, 1h trial training for their academy):
https://www.powerquery.training/
Modeling data and DAX:
• Understanding “the model” in PowerBI, free webinar (“Strengthen Your Data Modeling Skills with Power BI”) by Kasper de Jonge:
https://www.kasperonbi.com/on-demand-webinar-strengthen-your-data-modeling-skills-with-power-bi/
• (Free) Intro courses about DAX and Data Modeling: https://www.sqlbi.com/training/
• MS Business Application Summit Session by Marco Russo (Microsoft Power BI: Deep dive into DAX evaluation context):
https://www.youtube.com/watch?v=teYwjHkCEm0
• Super useful resource about the DAX language itself: https://dax.guide/
• Session @ SQL Bits by Alberto Ferrari (Time intelligence in DAX): https://www.sqlbi.com/tv/time-intelligence-in-dax-sqlbits-x/
Power BI Service:
Best thing is to subscribe to the monthly newsletter of the PowerBI blog to stay up-to data about the newest features (https://powerbi.microsoft.com/en-
us/blog/) and also have from time to time a look to the PowerBI YouTube channel when the videos summarizing/ explaining the new features of the
monthly releases are posted (https://www.youtube.com/user/mspowerbi/featured)

Microsoft Power BI exam 70-778 preparation workshop

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Microsoft Power BI exam 70-778 preparation workshop