DISTINCT

In the Ultra Transcenders books

DBX-DEP

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

Terms in this definition

• Once flow

  A flow that executes a single time and repeats only if the pipeline is fully refreshed. It's a common choice for a first full load ahead of a change feed, and that refresh becomes dangerous once the original files no longer exist.

• SELECT

  A DML command in SQL used to retrieve rows from one table or several.

• Set

  Secret permission in Key Vault for writing secrets; some older material refers to it as Create.

Related terms

• AI landing zone

  There is no distinct AI landing zone to build. According to the Azure landing zone FAQ, AI workloads simply go into normal workload landing zones beneath the platform you already have.

• Approximate aggregate functions

  Built-in SQL functions, including approx_count_distinct, approx_percentile and approx_top_k, that give up exactness in return for faster, cheaper results.

• Automatic rebalance

  A vSAN cluster option that shifts components across capacity devices when the gap in usage between any two exceeds a threshold, 30% unless changed. VCF advises turning it on to keep data evenly spread, despite more resync traffic when hosts join; it is distinct from reactive rebalancing, which begins once a device is 80% full.

• Automatic statistics

  When queries run against the Fabric Data Warehouse or the SQL analytics endpoint, the engine creates statistics (histograms, cardinality and average column length) on columns used for filtering, joining, grouping, sorting or DISTINCT. The histogram objects are named with a _WA_Sys_ prefix.

• Backup Operators

  Members can sign in to and shut down a Windows computer, and back up or restore any file on it regardless of permissions. Distinct from Azure's Backup Operator role.

• Cardinality

  How many different values a column holds. Columns with many distinct values compress badly in Import mode, so cutting them down makes the model smaller; this is separate from the cardinality of a relationship, such as one-to-many.

• Connection strings

  A distinct group of App Service settings, aimed mostly at .NET applications, that reaches the app as environment variables with a prefix. Apps on other stacks usually rely on app settings instead.

• Control plane

  Management layer used to create, configure and remove resources, as distinct from the data plane where they are used. Azure Resource Manager fills this role for Azure, and in AKS Azure operates the Kubernetes control plane on your behalf.