Active relationship Modeling
Only one relationship path between two tables can be active. Inactive ones (dashed lines) are used on demand with USERELATIONSHIP.
Power BI in plain English
A
Advanced Editor Power Query
The Power Query window that shows a query's full M code, so you can read, rename or edit the steps by hand.
Aggregation table Performance
A small pre-summarized table that answers most queries instantly, while the big detailed table is used only for drill-down.
Anti join Power Query
A join that keeps only the rows with no match in the other table. Ideal for finding orphan keys and data quality problems.
App Basics
A read-only package of reports and dashboards published from a workspace to a wide audience, with its own navigation. Audiences let different groups see different pages.
Append Power Query
Stacks queries with the same columns on top of each other, adding rows. The Power Query version of SQL UNION.
Applied steps Power Query
The ordered list of transformations in a Power Query query. Order matters: each step works on the output of the one above it.
Assume referential integrity Storage modes
A DirectQuery relationship setting that promises every fact key exists in the dimension, so Power BI can use faster INNER JOINs.
Audience Basics
A group inside an App that sees a chosen subset of its reports and pages.
Auto date/time Modeling
A Power BI option that silently creates a hidden date table for every date column. Turn it off in real models: it bloats the file.
B
Best Practice Analyzer Tools
A Tabular Editor feature that checks a model against rules (naming, formatting, performance) and lists violations.
BLANK DAX
DAX's empty value. Visuals hide rows where every measure is BLANK, which keeps them tidy.
Bookmark Visuals
A saved state of a page (filters, visibility, sort) for storytelling, toggles and reset buttons.
Bridge table Modeling
A small table of unique keys that sits between two tables whose link would otherwise be many-to-many.
Build permission Service
Permission that lets someone create their own reports on a semantic model, or query it from Excel, without editing it.
C
CALCULATE DAX
The DAX function that evaluates an expression under changed filters. It can add, replace or remove filters.
Calculated column Modeling
A column computed row by row with DAX at refresh time and stored in the model. Use it when you need to slice or filter by the result.
Calculated table Modeling
A table created with a DAX expression (e.g. CALENDAR or SUMMARIZE) and stored in the model at refresh.
Calculation group DAX
Reusable modifiers (YTD, prior month, currency…) that apply to any measure, so 10 measures × 5 variants doesn't mean 50 measures.
CallbackDataID Performance
A marker in a query plan meaning the storage engine had to call back to the formula engine for each row. A common sign of slow DAX.
Capacity Fabric
Purchased compute (F SKUs, measured in capacity units) that powers workspaces and features such as XMLA, deployment pipelines and large models. PPU is a per-user alternative for Power BI features.
Capacity Metrics app Fabric
The admin app that shows how much capacity each item consumes and when throttling happens.
Cardinality Modeling
(1) For relationships: one-to-many, one-to-one or many-to-many. (2) For columns: how many distinct values a column has. High cardinality compresses badly.
Column profiling Power Query
Power Query's built-in data checks: % valid/error/empty, distinct and unique counts, and value statistics. By default it only looks at the top 1,000 rows.
Composite model Storage modes
A model that mixes storage modes or sources, e.g. DirectQuery facts with Import dimensions, or a shared model extended with local tables.
Conditional formatting Visuals
Colours, icons or data bars driven by values or rules, so exceptions stand out.
Context transition DAX
When CALCULATE, or a measure reference, runs inside a row context, the current row turns into an equivalent filter.
Cross-filter direction Modeling
Which way filters flow across a relationship. Single (dimension → fact) is the safe default. Both can cause ambiguity and slower queries.
Cross-highlight Visuals
What happens to other visuals when you click a data point: filter (remove the rest) or highlight (show the matching share). Control it with Edit interactions.
CROSSFILTER DAX
Changes a relationship's filter direction, or turns it off, inside one measure only.
Custom function Power Query
A reusable M function you write once and invoke on many columns or queries, e.g. to clean a money column.
D
Dashboard Basics
A single page in the Service made of tiles pinned from one or more reports. Good for monitoring and alerts, but no slicers and limited interaction.
Data alert Service
A notification when a dashboard tile's number crosses a threshold you set.
Dataflow Fabric
Power Query that runs in the cloud and is reused by many semantic models. Gen2 in Fabric can write its output to a Lakehouse or Warehouse.
Date table Modeling
A continuous table of dates with Year/Month/Quarter columns, marked as a date table. Time intelligence needs one.
DATEADD DAX
Time intelligence functions that shift or build date ranges, e.g. DATEADD(Dates[Date], -1, MONTH) = the same dates one month earlier.
DAX DAX
Data Analysis Expressions: the formula language for measures, calculated columns, calculated tables and security rules.
DAX Studio Tools
A free tool for writing and timing DAX queries, reading query plans and measuring model size.
Delta table Fabric
An open table format (Parquet files plus a transaction log) that Fabric uses everywhere.
Deployment pipeline Deployment
A Service feature that moves content Dev → Test → Prod, with rules that swap data sources or parameters per stage.
Dimension table Modeling
A table that describes things you filter and group by: product, customer, region, date.
Direct Lake Storage modes
A Fabric storage mode that loads Delta tables straight from OneLake into memory: close to Import speed without import refreshes. It can fall back to DirectQuery.
DirectQuery Storage modes
Data stays in the source, and every visual sends a live query. It is always current, but slower and with some DAX limits.
Distinct vs unique Power Query
Distinct = how many different values exist. Unique = how many values appear exactly once.
DIVIDE DAX
Safe division that returns BLANK (or a value you choose) instead of an error when dividing by zero.
Drill down Visuals
Moving down a hierarchy within the same visual, e.g. Year → Quarter → Month.
Drillthrough Visuals
Right-click a data point to jump to a detail page filtered to that item (e.g. one customer).
Dual storage mode Storage modes
A table that acts as Import or DirectQuery depending on the query, typically used for dimensions in composite models.
E
Enable Load Power Query
The query setting that decides whether a query's result becomes a table in the model. Turn it off for staging or helper queries.
Endorsement Governance
Trust labels on content. Promoted = 'recommended'. Certified = reviewed and approved by people the admin authorized.
Enter Data Basics
A Power BI Desktop button that creates a small table by typing or pasting. It is handy for practice data, but it can't be refreshed from a source.
Explicit measure DAX
A measure you write in DAX. An implicit measure is the automatic sum Power BI creates when you drag in a numeric column. Prefer explicit measures.
F
Fact table Modeling
The table of events or measurements (sales lines, clicks, stock snapshots): many rows, numbers and keys.
Field parameter Visuals
A slicer-driven switch that changes which measure or column a visual uses.
Filter context DAX
The set of filters that applies to one calculation: slicers, visual rows and columns, page and report filters and cross-highlighting. It is why the same measure shows a different number in each cell.
Filter pane Visuals
The side pane with visual-, page- and report-level filters. Authors can lock or hide these filters.
Formula engine Performance
The single-threaded part of the engine that handles complex logic. Too much time here usually means the DAX needs a rewrite.
G
Gateway Service
Software on a machine in your network that lets the cloud Service reach on-premises data for refresh or DirectQuery.
Git integration Deployment
Connecting a Fabric workspace to a Git branch (Azure DevOps or GitHub) so content is version-controlled and reviewable.
Governance Governance
The policies that keep self-service BI trustworthy: who can publish, tenant settings, certified models, labels, naming and monitoring.
Grain Modeling
The level of detail one row represents, e.g. one order line or one region per category per month. Mixing grains without care causes double counting.
H
Hierarchy Modeling
An ordered set of columns (Year → Quarter → Month) that users can drill down through.
Hybrid table Storage modes
One table with imported history partitions plus a DirectQuery partition for today's live data.
I
Import mode Storage modes
Data is copied into Power BI's compressed memory engine. The fastest option, but it needs refreshing.
Incremental refresh Performance
Refreshing only recent date partitions (e.g. the last 3 days) and keeping older history, instead of reloading everything.
Iterator DAX
A function ending in X (SUMX, AVERAGEX, MAXX…) that evaluates an expression row by row over a table, then aggregates the results.
K
KEEPFILTERS DAX
Makes a CALCULATE filter intersect with the existing filter instead of replacing it.
L
Lakehouse Fabric
A Fabric item holding files plus Delta tables. It is built for Spark and notebooks and has a read-only SQL endpoint.
LASTNONBLANK DAX
Returns the last date that actually has data. The core of semi-additive measures like stock on hand.
Limited relationship Storage modes
A relationship between tables from different sources in a composite model. It has no guaranteed one side and behaves slightly differently.
Lineage view Service
A diagram of how sources, dataflows, models, reports and dashboards depend on each other.
Live connection Storage modes
A report that connects to an existing published semantic model and uses its model as is.
M
M Power Query
The formula language behind Power Query. Every step you click is written as a line of M, which you can read and edit in the Advanced Editor.
Many-to-many Modeling
A relationship where neither side's key is unique. It is supported, but it needs care. A bridge table often gives clearer behaviour.
Matrix Visuals
Power BI's pivot-table visual: rows, columns, values, subtotals and drill-down.
Measure DAX
A DAX formula computed at query time for whatever filters apply to that cell. Not stored, and it is what every number on a visual should be.
Medallion architecture Fabric
Bronze (raw) → Silver (cleaned) → Gold (business-ready) layers of data, each more trustworthy than the last.
Merge Power Query
Joins two queries side by side on matching key columns, adding columns. The Power Query version of a SQL JOIN or VLOOKUP.
Microsoft Fabric Fabric
Microsoft's all-in-one analytics platform. Data integration, engineering, warehousing, real-time and Power BI share one storage layer called OneLake.
Mobile layout Visuals
A separate portrait layout you design for each page so reports read well on phones.
My workspace Basics
Your personal workspace in the Service. Fine for experiments. Team content should live in a shared workspace.
N
Notebook Fabric
An interactive code document (PySpark, Python, SQL) used in Fabric for data engineering and data science.
O
Object-level security Security
Hides whole tables or columns (e.g. Salary) from certain roles. It is set with Tabular Editor.
OneLake Fabric
Fabric's single organization-wide data lake. Tables are stored once, in Delta format, for every engine to read.
P
Parameter Power Query
A named value, such as a server, file path or environment, that queries read instead of a hard-coded value. You can change it in the Service without editing the file.
Parent-child hierarchy Modeling
Rows that point to another row in the same table, such as an employee's ManagerKey. DAX's PATH functions flatten it into levels.
Partition Performance
A slice of a table (often by date) that can be refreshed on its own.
PATH DAX
DAX functions that turn a parent-child table into a text path ('1|2|6|8') you can split into levels or test for membership.
PBIP Deployment
Power BI Project format: the same report saved as a folder of readable text files (TMDL for the model, JSON for the report) so Git can track and compare changes.
PBIX Basics
The single binary file Power BI Desktop saves: queries, model, report pages and, in Import mode, the data itself.
Performance Analyzer Performance
A Desktop pane that records how long each visual takes, split into DAX query, visual display and other.
Power BI Desktop Basics
The free Windows application where you build reports: connect to data, shape it, model it and design pages. The file you save is a .pbix or a Power BI Project (.pbip).
Power BI Service Basics
The cloud website (app.powerbi.com) where reports are published, shared, refreshed on a schedule and turned into dashboards and apps.
Power Query Power Query
The data preparation tool in Power BI, Excel and Fabric. Every click becomes a recorded step that replays on each refresh.
Publish to web Governance
Makes a report PUBLIC on the internet with no sign-in. Never use it for internal data. Admins often disable it.
Q
Query folding Power Query
When Power Query translates your steps into the source's own language (usually SQL) so the source does the work. Faster refreshes, and required for efficient incremental refresh.
R
RangeStart / RangeEnd Power Query
Two reserved Date/Time parameters that incremental refresh uses to load one date partition at a time.
RANKX DAX
Ranking functions: RANKX ranks items by an expression, and TOPN returns the top N rows of a table.
Reference Power Query
A new query that starts from another query's output and stays linked to it. Use it to build staging → clean layers without copying steps.
Relationship Modeling
A link between two tables on a key column that lets filters flow from one table to another.
REMOVEFILTERS DAX
The DAX functions that remove filters inside CALCULATE. REMOVEFILTERS and ALL ignore every filter on the given columns or tables. ALLSELECTED keeps what the user selected. ALLEXCEPT keeps the listed columns.
Report Basics
One or more interactive pages of visuals built on one semantic model. Users can filter, slice, drill and hover.
Role-playing dimension Modeling
One dimension used in several roles, e.g. a Date table linked to both OrderDate (active) and ShipDate (inactive).
Row context DAX
The idea of 'the current row' while DAX walks a table (calculated columns and iterators). It does not filter other tables by itself.
Row-level security Security
Rules that filter which rows each user sees in the same model. Static = a fixed role per group. Dynamic = one role using the signed-in user's email and a mapping table.
S
Scheduled refresh Service
Automatic reloads of an Import model in the Service: up to 8 a day with Pro and 48 a day on capacity.
Selection pane Visuals
The pane that lists every object on a page so you can rename, group, show or hide them. Essential for bookmark toggles.
Semantic model Basics
The tables, relationships, measures and security rules behind a report. Many reports can share one semantic model. It was called a 'dataset' before 2023.
Semi-additive measure Modeling
A number that adds up across some dimensions but not time, like stock on hand or account balance. Across time you take the last value, not the sum.
Sensitivity label Security
A Microsoft Purview label (e.g. Confidential) that travels with data exported to Excel, PowerPoint or PDF.
Server Timings Performance
A DAX Studio view that shows the storage engine vs formula engine time and every storage engine query for one DAX query.
Shortcut Fabric
A OneLake pointer to data stored somewhere else, used without copying it.
Slicer Visuals
An on-canvas filter control (list, dropdown, date range…) that users click to filter the page.
Slowly changing dimension Modeling
How a dimension handles changes. Type 1 overwrites the old value. Type 2 adds a new row with valid-from and valid-to dates so history stays correct.
Snowflake schema Modeling
A star whose dimensions are split into chains of tables (Product → Subcategory → Category). In Power BI you usually flatten these back into one dimension.
Star schema Modeling
A fact table in the centre joined one-to-many to dimension tables around it. The shape Power BI is designed for.
Storage engine Performance
The fast, multi-threaded part of the engine that scans compressed data. Good DAX gives it most of the work.
Subscription Service
An email with a snapshot of a report page or dashboard, sent on a schedule.
Surrogate key Modeling
A meaningless whole-number key (CustomerKey = 101) used instead of a text business key. It compresses better and allows history tracking.
Sync slicers Visuals
A feature that makes one slicer's selection apply on several report pages.
T
Table.Buffer Power Query
An M function that loads a table into memory once, so repeated lookups don't re-read the source. Useful, but it stops query folding.
Tabular Editor Tools
A tool for editing models directly: calculation groups, OLS, scripting, bulk edits and the Best Practice Analyzer.
Tenant settings Governance
Organization-wide switches in the Power BI/Fabric admin portal (export, publish to web, sharing…), often enabled only for specific security groups.
Thin report Architecture
A report file that contains no model of its own and connects live to a shared semantic model in the Service.
Time intelligence DAX
DAX functions for calendar comparisons: year-to-date, prior month, same period last year, rolling windows. They need a proper date table.
TMDL Deployment
Tabular Model Definition Language: a readable text format for semantic models, one file per table. It is ideal for Git diffs.
Tooltip page Visuals
A small custom report page shown when hovering a data point, filtered to what you hovered.
TREATAS DAX
Applies the values of one column as a filter on another column that has no physical relationship: a 'virtual relationship'.
U
Unpivot Power Query
Turns wide columns (Jan, Feb, Mar) into rows of Attribute and Value. Models and DAX prefer tall, narrow tables.
Usage metrics Service
Built-in reports showing who viewed which report pages and how often.
USERELATIONSHIP DAX
Activates an inactive relationship for one calculation only, e.g. to count by ship date instead of order date.
USERPRINCIPALNAME Security
A DAX function that returns the signed-in user's login (usually their email). The key to dynamic RLS.
V
Variables DAX
VAR … RETURN stores an intermediate result once inside a measure. Measures become easier to read, easier to debug and often faster.
VertiPaq Performance
The in-memory column-store engine behind Import mode. It compresses each column. Fewer distinct values means a smaller, faster model.
View Native Query Power Query
Right-click a step to see the SQL that Power Query sends to the source. If the option is greyed out, folding has stopped at or before that step.
W
Warehouse Fabric
A Fabric item with a full T-SQL (read/write) data warehouse experience, stored as Delta tables in OneLake.
Window functions DAX
WINDOW, OFFSET, INDEX and RANK compute running totals, previous-row values and positions over a sorted set of rows.
Workspace Basics
A shared folder in the Service that holds reports, semantic models, dataflows and other items, with roles: Admin, Member, Contributor and Viewer.
X
XMLA endpoint Deployment
An enterprise connection point (on capacity or PPU) that lets tools like SSMS and Tabular Editor read and write published models.