3.1.1. Table and Column Properties

💡 First Principle: Properties are metadata that change how the model behaves without changing the data. A good model makes the right thing easy for report authors: the correct field is visible, named in business language, formatted, sorted sensibly, and summarized appropriately, so authors don't need to know the model's internals.

Column properties (Model view or the Column tools ribbon) that the exam names:

• Data type and format: currency, percentage, decimal places, thousands separator, date formats. Set once on the column or measure, inherited by every visual.
• Sort by column: sorts one column by another's values. Month Name sorted by Month Number shows January to December instead of April, August, December. The sort column must have one value per value of the sorted column (one MonthNumber per MonthName).
• Data category: tells Power BI what a column represents: Address, City, Country/Region, Postal Code, Latitude, Longitude for maps; Web URL and Image URL for links and images in tables. Correct categories make map visuals geocode accurately.
• Default summarization: Sum, Average, Count, Don't summarize, and so on. Set Don't summarize on numeric columns that aren't additive, such as Year, ProductKey, or UnitPrice, so dragging them into a visual doesn't produce a meaningless sum.
• Hide in report view: hides keys, technical columns, and columns used only by measures. Hidden fields remain usable by DAX and relationships.
• Display folders: organize measures and columns into folders in the Data pane.
• Name and description: business-friendly names and descriptions appear as tooltips in the Data pane and improve Copilot's understanding of the model. Synonyms help natural-language features match user phrasing.
• Is nullable / key column, summarize by, row label and similar advanced properties exist; know they're set in Model view properties.

Table properties include name, description, storage mode (Import, DirectQuery, Dual in composite models), Is hidden, and Mark as date table (3.1.4). Measures can be placed on a dedicated measures table (often a table with no visible columns) to keep the Data pane tidy.

⚠️ Exam Trap: "Month names appear in alphabetical order in the visual" is fixed with Sort by column (MonthName sorted by MonthNumber), not by sorting the visual or renaming months with numeric prefixes. Sorting the visual by the measure changes the order to value-based, which isn't what's asked.

Reflection Question: Why should Year and CustomerKey columns be set to Don't summarize, and what visible symptom appears in a report when they aren't?