Our Top 5 Areas to Study for the PL-300 Exam!

Are you studying for the PL300 PowerBI data analyst exam and feeling overwhelmed? In this video, I'm going to summarize some of the top things you should focus on when studying for that exam. Hello everyone, my name is Angelica Chuan and I'm going to talk to you today about some of the biggest concepts and some of the things you don't want to overlook on that PL300 study guide when you're preparing. A big mistake people make in preparing for this exam is treating the exam like a memorization test. The PL300 is not one of the fundamentals exams, but instead an exam that's going to test you on the application of these skills. Trying to remember every button in the UI definition or DAX function. That's not really what Microsoft is trying to test you for on this PL300 exam. Instead

there are a few key concepts that you will see over and over again appearing in different themes and different ways on the exam. And if you understand these, everything else becomes easier. Let's start with one of the things that people underestimate the most for that PL300 exam and in PowerBI in general, and that's data modeling. In PowerBI, your model is the foundation of

everything. your visuals, the performance of your model, your DAX results, and even rowle security. Microsoft expects you to understand the star schema, which is the preferred modeling approach in PowerBI development. This is a design where a central fact table stores measurable data and connects to multiple denormalized dimension tables. With that you need to know the difference between fact and dimension tables and be able to identify those. Fact tables are what you are measuring. These store observations and events. Uh examples of these include things like sales orders, stock balances, logs, and even occurrences. Your dimension tables describe business entities like customers, products, sales territory, and date. I like to refer to these as the who, what, when, and where in modeling. Dimension tables contain a relatively small number of rows, while your fact table will contain many more rows and continue to grow over time. You'll also see questions about relationships and cardality. And you must understand how relationships affect filtering and your analysis. This includes understanding that cardality

especially when it comes to the one to many relationship versus many to many relationships. One to many relationships, an example of this, a common one you'll see is like customer table to sales table. Each customer appears once in that customer dimension, but that same customer can appear many times in the sales table because the sales table represents one row per transaction and we might have some repeat customers who are coming back to us multiple times to purchase more of our product. Many to many relationships are a little bit different and sometimes a little more complex to understand. A common example of this for all my fellow teachers out there is looking at students to classes. So you have a student's table and a classes table and a student can enroll in many classes and a class can have many students. There is

no single one side here because both tables can contain repeating values. You'll also want to know and understand something called roleplaying dimensions. Role- playing dimensions are dimensions that can filter related facts differently, particularly the date dimension or date table. And these are used to support those different analytical perspectives like order date, ship date. If your model is wrong, your results in your visuals and therefore some of those answers might be incorrect. So you need to have these modeling concepts down before you sit for that PL300 exam. With modeling comes another important concept. Next up, we have DAX. And this is where a lot of people panic unnecessarily. Don't get me wrong, DAX can be hard and it can be difficult to master. And the PL300 is not necessarily testing your

memorization of every DAX function. It's testing whether you understand how DAX evaluates data. When working with DAX, one of the most important things to understand is the difference between row context and filter context. Row context means DAX is evaluating your data run one row at a time. You see this most often in calculated columns where the formula runs separately for each row in a table. Filter context on the other hand is about which rows are included in a calculation based on slicers, filters, and visuals. Filter context can come from various places in your report based on your interactions and based what's filtering down that data. And it's why measures change as users interact with a report. There are also a few key DAX functions that I would pay close attention to when you're studying and preparing for that exam. The PL300 probably wants to make sure you recognize and understand the use of the calculate function. It's one of the most important functions in DAX because it allows you to override filter context and to change the filter context. You should also know the difference between

sum and sumx. Sum is simply going to add up the values in a column. While sumx is going to iterate row by row, evaluate an expression for each row, summing those results. You also want to make sure you understand when to use a calculated measure versus a calculated column. You're going to see this come up multiple times. Calculated columns can be defined by a DAX expression and are evaluated row by row. So you will see the results in your table view. columns will take up more space in your model and can significantly impact the performance if you're using it over and over again in those report visuals. Measures are a little different. Measures are dynamic and they're not evaluated row by row like a column is in DAX. So you won't see the results of your measures produced on that table view. Instead, the measure value can only be seen in a visual. DAX measures run at query time and are not stored in the model the same way a DAX calculated column is. Here's a simple rule to keep in mind when you're taking that exam. Use columns when you need to perform rowle calculations and use measures when the calculation might be a little more complex and you need to aggregate data and aggregated data that's going to change dynamically based on user interaction. expect to see questions that are more so testing your knowledge like which DAX expression returns the correct result not what does this DAX function do now let's talk about the power query editor and what you can do here because this is another area people underestimate on that PL300 exam

Microsoft isn't testing whether you can click buttons in Power Query they're testing whether you understand how to profile clean and shape data before it ever reaches the model in the PowerBI desktop. From the exam perspective, Power Query breaks down into a couple of buckets. One, the first major one is profiling and cleaning the data. You're expected to know how to evaluate data using the column statistics and column properties features. There are three main ones. Column distribution shows you the distribution of data within a column. This includes the counts of distinct and unique values. Column profile gives you a more indepth look into the statistics within the column for the first 10,00 rows of data unless you switch to evaluating based on the entire data set. Column profile gives you a breakdown of column statistics and value distribution sections and column quality which is going to show you the uh percentage of values in the column that are resulting in empty nulls or are completely valid. You'll also want to make sure you can identify and fix null values, how to resolve inconsistencies in your model, and what to do when data quality or data errors result in the model and how to resolve them. Like when you are loading data and you're refreshing your report and when you refresh that report, you find out that the location of a file that was once connected has changed or moved and now you can no longer refresh the report and find the new data. The second bucket is transforming and loading the data. And this is where a lot of exam scenarios live. You want to be comfortable with choosing the appropriate column data types to store your columns for filtering those columns later on. You want to be familiar with creating and transforming columns and using that query language. You want to know how to group and aggregate rows and when to use that group by function in the Power Query editor. You want to know the difference between pivoting, unpivoting, and transposing data. And know that these are different in your model. Pivoting and pivoting are the opposite of one another. And transposing is transposing that data from columns to rows or rows to columns. You want to understand how to convert semi-structured data like JSON and CSV files into proper tables that can be analyzed in your model. You may also see questions about model preparation like

creating those facts and dimensions and largely this will be done in the power query editor before you load it into your model. You may need to know when to use reference versus duplicate queries. Duplicate queries will act completely independently of the model or the query they were duplicated from. Well, reference is always going to uh contain that single source stuck at initially referencing back to the source table that you referenced initially from. Merging and appending queries is another big one you want to know the difference between and many people confuse the two. When you're trying to merge queries, you are joining columns from one table to columns of another. And appending queries involves adding rows from one table to rows of another. With both of these options, you can merge into an existing query or merge as new. And the same applies to the appending queries transformation. You may also need to create an appropriate key for model relationships when one doesn't naturally exist. The key idea to remember in your

PL300 exam is Power Query is where you prepare data for analysis, not where you necessarily calculate insights. Let's shift now from the PowerBI desktop to talk about the PowerBI service a little bit. Microsoft wants you to understand security and sharing in PowerBI. This is going to include workspace roles and knowing which workspace roles should be applied and to whom. You have the admin, member, contributor and viewer role. The admin role has full control of the workspace. They can manage users and roles. They can update or delete the workspace. They can delete users and publish and manage apps and app permissions. Next up is the member. The member has a little less permissions. They can create, edit, and delete content. They can publish and manage apps and add users with lower permissions. But they cannot manage the workspace itself and therefore they cannot delete the workspace. Your contributor role. This role can create and edit content and if allowed by admin, they can update the app. And the one thing you want to know with this is they can't publish a new app or manage access. Our viewer can only interact and view content within apps and within that workspace. They have no ability to create, edit, or manage anything else at all. Next up in this section, one big thing you want to make sure you understand completely is rowle security. Rowle security, also referred to as RLS in PowerBI, allows you to restrict which rows of data each user can see. It's based on rules defined in the model using DAX. You can set up simple basic also known as static role level security to filter down to let's say particular regions within your uh model. For example, if you wanted to create a role for each sales territory so that when a user is assigned to this role, they can only see the role assigned to the sales territory country when it is equal to the United States or to France or Canada. You can also create dynamic security using a function known as user principal name. User principle name allows you to capture the state of the logged in user in the PowerBI desktop and the PowerBI service and those filters that are applied are automatically applied whenever someone is assigned that viewer level access in the PowerBI report. Most importantly you want to know here is that the viewer is the only role that role security will be enforced upon. Admin member contributors are going to bypass that RLS and see all data. So rowle security only filters rows. It is not object level security. If you do not want someone to see a particular report, then you shouldn't share it with them. A very common trap that you may find yourself in on an exam is thinking workspace access and workspace app access are the same. Workspace apps can have multiple audiences with varying levels of access and permissions and workspaces have different roles that can be assigned. Another trap you may find yourself in is assuming that RLS that role level security applies to everyone including admin member and contributors. Important reminders only viewers are affected by role level security and keep that in mind throughout any of those questions that you see on security. Questions in this area often feel deceptively simple, but they're testing whether you understand how PowerBI is used in real organizations. Visual behavior and interactions is one that surprises many people. There are a lot of concepts and

skills listed in this section. And the PL300 is not testing your knowledge on making reports look pretty. Instead, it focuses on how visuals behave and how visuals behave when users interact with them. You should understand a few main things. You want to know the key difference between drill down and drill through. Drill down lets users move deeper within the same visual by navigating through a hierarchy, such as going from year to quarter to month within a chart or a visual. Drill through allows a user to go from one report page to a more detailed report page that's filtered to a selected data point by clicking let's say a customer and open up opening up a customer details page. In short, drill down allows the user to stay on the same visual and explore levels within a hierarchy, while drill through navigates to another report page for deeper context. Cross filtering and cross- highlighting is another one that trips some people up on the exam. What happens when a user clicks on a bar in a bar chart? How do the other visuals in the report respond? What is the natural behavior? Bar charts and column charts typically are going to highlight while visuals like a card or a matrix are going to filter as that is the default option. You want to know the difference why one visual filters and instead another will highlight and you want to keep that in mind. Another thing you want to be familiar with is the process of configuring tool tips and navigation behavior in your reports. For this section on the exam, you want to think less about where do I click and more about what does the user experience need to be when they interact with this report. A bonus I want to throw in here

is knowing what to expect and how to prepare for the case study section on the exam. One of the biggest things that people overlook on the PL300 is the case study section. And this part of the exam feels very different from the rest. In the case study section, you're given a single business scenario. Usually it contains multiple tabs of information. Things like a background, data sources, business requirement, technical requirements, and possible issues that the business is currently facing. Then you answer multiple questions based on that same scenario. What catches people offguard in this section is you can't move freely between those sections. Meaning you can't move between the section that's just set for your case study and the rest of the multiplechoice or the drag and drop and build questions on the exam. Once you move past the case study, you cannot go back. And the questions in this section are much more context heavy. Microsoft isn't testing isolated facts here. They're testing whether you can read business requirements carefully and identify constraints and priorities and make the best PowerBI decision based on that scenario. The best way to prepare for this section is to practice slowing down before even looking over the entire scenario in each of those tabs. Briefly look at each of those questions. Then go back, identify who the users are, what the requirements are for those users, what are the data sources, and what are the core business goal is for this scenario. If you treat the case study like a real consulting scenario and not a rapidfire quiz, you'll avoid one of the most common reasons people lose easy points on that PL300 exam. All right, let's wrap up and recap the most

important things to focus on that PL300 exam when you are studying and preparing. First up, data modeling is everything and it affects everything. So, be sure you understand these concepts like star schema and facts and dimensions as well as birectional filtering. DAX concepts matter more than function definition. Three, power query decisions affect storage and performance. Next up, security and sharing are tested subtly. And last, visual behavior matters more than formatting. If you're studying for that PL300 exam, my biggest recommendation to you is to put yourself into some practice scenario-based questions and review those. You can do this by taking the Microsoft practice exam or using a Cert Prep program like our CERT XP that contains test preparation questions. After you choose an answer, when you are studying using those practice questions, make sure you explain the why. Explain why it is correct. Forcing yourself to find the reasoning solidifies that you understand the feature and the function and the why behind it, not just where or how to do it in PowerBI. You want to make sure you have hands-on experience. Getting hands-on experience is the best way to prepare for a skills-based exam. So, taking the time to develop a PowerBI report from start to finish allows you to learn the nuances and intricacies of PowerBI report development and will make you feel more comfortable and confident when answering those questions on the exam. That mindset shift alone can be the difference between passing and failing. If you want access to my PL300 review course and XP, you can sign up for an annual subscription using the code prag. works/angelico40. I'll include a link in the description below for you to use later on. I hope you enjoyed this video and good luck studying for that PL300 exam. I know you'll be a certified PowerBI data analyst in no time. I hope you enjoyed this video and as always, I'll see you in the next one.