Tech Exam Prep

Tech Exam Prep

By Ran Chen, EA, CFP®EducationHow ToCourses
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Tech Exam Prep episodes

  • [PL-300] 26, DAX Syntax, Row Context, and Filter Context
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - The crucial distinction between scalar values and table results in DAX functions for the PL-300 exam.
    - How row context differs from filter context and how iterators like SUMX operate line by line.
    - Why context transition occurs using CALCULATE and how it modifies the active filter context.
    - How DAX variables evaluate once upon definition and retain their frozen values across context changes.
    - How to avoid common exam traps involving identical-looking DAX expressions and evaluation order.
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    4 min
  • [PL-300] 25, Measures vs Calculated Columns and Tables
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - Differences in evaluation time and RAM storage between measures, calculated columns, and calculated tables.
    - Why calculated columns are required for slicers, visual axes, and table relationships.
    - How measures evaluate dynamically in filter context at query time without consuming memory storage.
    - Common PL-300 exam traps involving percentage aggregations and context transition in DAX.
    - Scenario-based decision rules for selecting calculated tables for role-playing dimensions and bridge tables.
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    5 min
  • [PL-300] 24, Creating a Common Date Table
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - How to generate date tables using DAX functions like CALENDAR and CALENDARAUTO, including fiscal year parameters.
    - The strict data requirements for a valid date dimension, including continuous date ranges and zero missing dates.
    - How to fix text column sorting issues in Power BI visuals using the Sort By Column feature.
    - The process and benefits of explicitly marking a table as a date table in Power BI Desktop.
    - How to manage active and inactive date relationships using USERELATIONSHIP and the D.A.T.E.S. mnemonic for exam success.
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    4 min
  • [PL-300] 23, Cross-Filter Direction and Relationship Paths
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - Default to single cross-filter direction to preserve query performance and avoid circular filter logic.
    - Use inactive relationships with the DAX USERELATIONSHIP function to analyze role-playing dimensions like Order Date and Ship Date.
    - Avoid enabling bidirectional filtering across schemas as it frequently causes performance degradation and ambiguous filter paths.
    - Resolve model ambiguity errors by ensuring only one active relationship path exists between any two tables at a time.
    - Always select the least complex data modeling configuration that satisfies reporting requirements to answer PL-300 questions correctly.
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    5 min
  • [PL-300] 22, Relationship Cardinality
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - How to select one-to-many, one-to-one, and many-to-many cardinality based on key uniqueness and table grain.
    - Why one-to-one relationships often indicate tables that should be merged in Power Query to reduce model complexity.
    - How to diagnose blank members in visuals caused by referential integrity gaps between fact and dimension tables.
    - Why duplicate keys in dimension tables force unwanted many-to-many relationships and how to fix them.
    - How to prevent ambiguous totals and double-counting caused by joining tables with mismatched grains.
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    4 min
  • [PL-300] 21, Role-Playing Dimensions
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - How to identify role-playing dimension scenarios involving Order Date, Ship Date, and Due Date on the PL-300 exam.
    - The differences between duplicating date dimensions and using inactive relationships in Power BI.
    - When to select duplicated tables to support independent, simultaneous slicers on a report page.
    - How to write DAX measures using CALCULATE and USERELATIONSHIP to activate inactive date relationships.
    - Common exam traps regarding dataset optimization, relationship limitations, and model maintenance tradeoffs.
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    4 min
  • [PL-300] 20, Table and Column Properties
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - How to configure Sort by Column to resolve chronological sorting issues for date and month fields in PL-300 scenarios.
    - The distinction between Data Type and Formatting properties, along with proper Data Category assignment for geospatial visuals.
    - Why setting Default Summarization to Do Not Summarize prevents incorrect aggregation of numeric identifiers like Zip Codes and Customer IDs.
    - Strategies for hiding technical surrogate keys and raw columns to simplify self-service reporting and improve Q&A natural language query accuracy.
    - Exam-tested techniques for using table and column descriptions to enhance metadata clarity for report creators.
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    4 min
  • [PL-300] 19, Star Schema Design and Model Granularity
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - How to distinguish fact tables from dimension tables to establish optimal one-to-many relationships.
    - How to handle granularity mismatches across different fact tables without introducing calculation errors.
    - Why flattening snowflaked dimensions improves filter context propagation and VertiPaq compression.
    - How wide flat tables degrade Power BI model performance and break time intelligence capabilities.
    - How to resolve many-to-many modeling challenges without relying on risky bi-directional cross-filtering.
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    4 min
  • [PL-300] 18, Relationship Keys and Query Load Settings
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - How to handle composite keys by concatenating columns or creating numeric surrogate keys in Power Query
    - Why data types must strictly match across related tables to ensure stable model relationships
    - How unchecking Enable Load creates connection-only staging queries without breaking downstream references
    - When to disable Include in Report Refresh for static historical data to reduce refresh duration
    - A practical mnemonic to remember key modeling and query load rules on the PL-300 exam
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    4 min
  • [PL-300] 17, Merge Queries vs Append Queries
    This podcast is made by Ran Chen, who holds an EA license, Insurance and Securities licenses (Series 6, 63, 65), and the CFP® designation. He is passionate about opening access to high-quality exam preparation resources and helping learners prepare more effectively for professional certification exams.
    In this episode you will learn:
    - How Merge Queries joins tables horizontally using matching key columns, while Append Queries stacks tables vertically.
    - The six join kinds in Power Query Merge operations, including default Left Outer and audit-oriented Left Anti joins.
    - How duplicate key values in a Merge table cause row count expansion and row duplication traps on the exam.
    - Why Append Queries requires identical column names and case sensitivity to avoid extra null-filled columns.
    - Clear scenario triggers to instantly choose between horizontal column enrichment and vertical row consolidation.
    For more free exam prep tools, practice questions, and AI-powered explanations, visit https://open-exam-prep.com/ or YouTube Channel: https://www.youtube.com/@Open-exam-prep
    5 min

About Tech Exam Prep

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Tech Exam Prep is a free, daily podcast by OpenExamPrep covering the most in-demand IT and technology certification exams — including CompTIA Security+, AWS Cloud Practitioner, CompTIA Network+, CCNA,…