DEFINE

In the Ultra Transcenders books

PL-300

Each book explains DEFINE in context, with comparison tables and the common traps.

Terms in this definition

• DAX query

  A query against a semantic model that returns a table, comparable to a T-SQL SELECT. It is written with EVALUATE, optionally preceded by DEFINE for query-only measures and variables and followed by ORDER BY, and it doesn't alter the model.

• FIRST

  A DAX function available only inside visual calculations. It fetches the value at the start of one axis of the visual's matrix, which makes it handy for comparing each point with the first; its opposite is LAST.

• EVALUATE

  Keyword that every DAX query must contain; whatever table expression follows it becomes the query's output. Clauses such as DEFINE, ORDER BY and START AT may be added if needed.

• Measure

  A figure like total revenue, worked out by aggregating fact table data wherever dimensions intersect within a semantic model.

• Agents (classic) API

  First-generation Foundry Agent Service API, based on threads, messages and runs. It is deprecated, replaced by conversations and responses, and retires on 31 March 2027.

Related terms

• Activator

  Rather than just displaying data as a dashboard does, this Real-Time Intelligence tool in Microsoft Fabric reacts to it. You define rules without writing code, and once a pattern or condition is spotted it can send an email or Teams message, or start a Power Automate flow or Fabric pipeline.

• Address space

  The CIDR block or blocks that define a VNet. Every subnet has to fall inside it; blocks can be added, or altered when nothing is using them.

• AMO

  A .NET client library that SSMS and Visual Studio use to administer Analysis Services servers and define their objects; for tabular models, TOM (the Tabular Object Model) builds on top of it.

• Automatic indexing

  By default, Azure Cosmos DB indexes all properties of all items in a container, so you don't need to define a schema or maintain secondary indexes yourself. Paths can be left out through an indexing policy.

• Container vector policy

  The vectorEmbeddings setting on an Azure Cosmos DB container, specifying for each vector path its number of dimensions, data type and distance function. You define it, together with vector indexes, when creating the container.

• Custom categories (Content Safety)

  Lets Content Safety detect categories you define, either in standard form (trained over several hours and retiring on 1 September 2026) or in rapid form from samples; for a handful of niche terms, a blocklist takes less effort.

• Custom log table

  Table in Log Analytics whose name ends in _CL and whose schema you define, populated through a DCR with data no standard table suits.

• Custom organization roles

  In GitHub Enterprise Cloud, you can define extra organisation roles granting chosen permissions across all repositories, beyond the predefined ones.