What is... A Schema?

In Databricks, a schema, also known as a database, is the second level of the Unity Catalog's three-level namespace hierarchy, which includes catalog, schema, and table. A schema organizes data and AI assets into logical categories that are more granular than catalogs, typically representing a single use case, project, or team sandbox. It can contain tables, views, volumes, models, and functions, providing a structured way to manage data access control and improve data discoverability.

In the context of tables, a schema is where tables reside, and it helps in logically grouping tables and other data objects for better organization and management.

Unity Catalog’s Object Model

Users must have the USE_SCHEMA data permission on the schema and its parent catalog,and they must have the SELECT permission on the table or view. Additionally, a table schema, which is not specific to Databricks, defines the structure of a table, including the table's columns, their data types, and any constraints on the data, such as primary keys or unique constraints