When switched on for a KQL database or table (it starts disabled), an Eventhouse exposes that data in OneLake in Delta format. Other Fabric engines, Direct Lake included, can then read it without anyone copying it.
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In the Ultra Transcenders books
Each book explains OneLake availability in context, with comparison tables and the common traps.
Terms in this definition
- KQL database
Lives within a Microsoft Fabric eventhouse and keeps tables that you query in KQL. One eventhouse may contain several of them, and each can hold many tables.
- Event
Table in Log Analytics where entries from Windows event logs are kept.
- Eventhouse
Holds one or more KQL databases and is where Real-Time Intelligence in Microsoft Fabric keeps time-stamped streaming events for analysis, indexed by the moment they arrive.
- OneLake
Built on Azure Data Lake Storage Gen2, it is the one logical data lake for an entire Microsoft Fabric tenant, provisioned automatically, and the place where every Fabric workload keeps its data.
- FORMAT
A DAX function that turns a value into text according to a format string, for instance "MMMM" to show a month's name. Since the output is text, numeric operations can't use it, and dynamic format strings were introduced to get around that.
- Direct Lake
Mode for Fabric semantic models that loads Delta or Parquet files from OneLake straight into VertiPaq, giving almost import-level performance without duplicating data.
- CRUD
Shorthand for create, read, update and delete, the four basic things you do with data. Data-plane roles in Azure Cosmos DB, for instance, authorise those operations on items.
Related terms
- OneLake integration
After each refresh, a semantic model with this option on writes its Import-mode tables to OneLake in Delta format, where a lakehouse can pick them up via a shortcut. Eventhouses do the same thing with OneLake availability.