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Reference guide

PL-300 Course Notes

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Section 1 Data Preparation Preview
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Summary

Data preparation starts with choosing the right connection pattern for the business requirement. Power BI Desktop can connect to files, databases, online services, Power Platform sources, Fabric items, and shared semantic models. PL-300 questions often test whether the model needs imported data, live query behavior, or reuse of an existing semantic model instead of building a new dataset from scratch.

Key Points

  • Import Mode: A storage mode that loads source data into the Power BI semantic model and serves report queries from the in-memory model after refresh.

Common Mistakes

  • Do not choose DirectQuery just because data is large; Import, DirectQuery, and Direct Lake depend on refresh, latency, source limits, and Fabric storage requirements.

Exam Tips

  • If the question mentions combining sources with different sensitivity, look for Power Query privacy levels.
Section 2 Data Modeling Preview
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Summary

Data modeling in PL-300 is about building a semantic model that answers business questions quickly and correctly. A star schema is the default design target: fact tables store transactions or measurable events, while dimension tables store descriptive attributes used for filters, slicers, grouping, and labels.

Key Points

  • Star Schema: A modeling pattern with fact tables connected to descriptive dimension tables for efficient filtering and aggregation.

Common Mistakes

  • Do not collapse facts and dimensions into one wide table when a star schema would make relationships and DAX simpler.

Exam Tips

  • If the answer choice separates facts from descriptive lookup tables, it is usually pointing toward star schema design.
Section 3 Visualization & Analysis Preview
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Summary

Visualization begins with the business question, not the chart gallery. Use bar and column charts for category comparison, line charts for trends over time, cards for single KPIs, tables or matrices for detailed lookup, maps for geography, and scatter plots when the question asks about relationships, clusters, or correlation between numeric measures.

Key Points

  • Scatter Plot: A visual used to compare two numeric measures and identify correlation, clusters, or outliers.

Common Mistakes

  • Do not choose a visual because it looks impressive; match it to comparison, trend, distribution, correlation, detail, or KPI intent.

Exam Tips

  • If the question asks about correlation or relationships between two numeric measures, choose a scatter chart.
Section 4 Power BI Security Preview
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Summary

Power BI security starts with workspace roles. Admin, Member, Contributor, and Viewer permissions control what a person can manage, publish, edit, or consume inside a workspace. Least privilege means giving users the smallest role that supports their job, such as Viewer for report consumption rather than Contributor.

Key Points

  • Workspace Role: A Power BI workspace permission level such as Admin, Member, Contributor, or Viewer that controls workspace capabilities.

Common Mistakes

  • Workspace Viewer access does not automatically grant Build permission on the semantic model.

Exam Tips

  • If users only consume curated reports, distribute a Power BI app rather than giving workspace edit roles.