Mirrors a database living in another system so it can be queried read-only from Unity Catalog over a Lakehouse Federation connection. Making one takes CREATE CATALOG, and on the connection you need ownership or CREATE FOREIGN CATALOG.
Read more: Microsoft Learn
In the Ultra Transcenders books
Each book explains Foreign catalog in context, with comparison tables and the common traps.
Terms in this definition
- Schema
The middle part of a Unity Catalog name (
catalog.schema.table), grouping tables, views, volumes, functions and models inside a catalog. A grant on it covers everything in it now and later, and nothing inside can be reached withoutUSE SCHEMA. - Chat message roles
Labels on chat messages: instructions go under system, the person's input under user, the model's previous answers under assistant, and results returned by a called tool under tool (or function).
- Unity Catalog
Azure Databricks' governance solution covering both data and AI in one place, with centralised permissions, auditing, data discovery and lineage.
- OVER
Gives a T-SQL window function its window: PARTITION BY, ORDER BY and, if wanted, a ROWS or RANGE frame. Rankings and running totals can then be worked out while every row is kept.
- Lakehouse Federation
Azure Databricks' approach to query federation: foreign catalogs and Unity Catalog connections expose outside databases and catalogs for governed, read-only queries, with work pushed down to the source when possible.
- Connection
Resource that attaches a virtual network gateway to its peer, which may be an ExpressRoute circuit, a second VNet gateway (Vnet2Vnet) or a local network gateway over IPsec. Resetting it recovers a single tunnel and avoids rebooting the whole gateway.
- 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.
- Catalog
The first level of Unity Catalog's
catalog.schema.tablenaming and the primary boundary for isolating data. Privileges granted on a catalog flow down to every schema and object it contains.
Related terms
- Authorised paths
Cloud storage locations specified when creating a foreign catalog for Hive metastore federation. Tables reached through the catalog have to live beneath these locations, so changing a table's location can't be used to get at other data.
- REFRESH FOREIGN
Updates, on request, what Unity Catalog knows about a foreign catalog, schema or table. Without it, federated metadata is updated automatically when queried.
- USE CONNECTION
The Unity Catalog permission that allows work through a connection, such as creating a foreign catalog or building pipelines, while keeping its credentials hidden.