Share via

Information schema

  • Article

Applies to: check marked yes Databricks SQL check marked yes Databricks Runtime 10.4 LTS and above check marked yes Unity Catalog only

The INFORMATION_SCHEMA is a SQL standard based schema, provided in every catalog created on Unity Catalog.

Within the information schema, you can find a set of views describing the objects known to the schema’s catalog that you are privileged to see. The information schema of the SYSTEM catalog returns information about objects across all catalogs within the metastore. Information schema system tables do not contain metadata about hive_metastore objects.

The purpose of the information schema is to provide a SQL based, self describing API to the metadata.

Entity relationship diagram of the information schema

The following entity relationship (ER) diagram provides an overview of a subset of information schema views and how they relate to each other.

ER diagram of information schema

Information schema views

Name Description
CATALOG_PRIVILEGES Lists principals that have privileges on the catalogs.
CATALOG_PROVIDER_SHARE_USAGE Describes provider share mounted onto catalogs.
CATALOG_TAGS Contains tags that have been applied to the catalogs.
CATALOGS Describes catalogs.
CHECK_CONSTRAINTS Reserved for future use.
COLUMN_MASKS Describes column masks on table columns in the catalog.
COLUMN_TAGS Contains column tagging metadata within a table.
COLUMNS Describes columns of tables and views in the catalog.
CONNECTION_PRIVILEGES Lists principals that have privileges on the foreign connections.
CONNECTIONS Describes foreign connections.
CONSTRAINT_COLUMN_USAGE Describes the constraints referencing columns in the catalog.
CONSTRAINT_TABLE_USAGE Describes the constraints referencing tables in the catalog.
CREDENTIAL_PRIVILEGES Lists principals that have privileges on the credentials.
CREDENTIALS Describes credentials.
EXTERNAL_LOCATION_PRIVILEGES Lists principals that have privileges on the external locations.
EXTERNAL_LOCATIONS Describes external locations.
INFORMATION_SCHEMA_CATALOG_NAME Returns the name of this information schema’s catalog.
KEY_COLUMN_USAGE Lists the columns of the primary or foreign key constraints within the catalog.
METASTORE_PRIVILEGES Lists principals that have privileges on the current metastore.
METASTORES Describes the current metastore.
PARAMETERS Describes parameters of routines (functions) in the catalog.
PROVIDERS Describes providers.
RECIPIENT_ALLOWED_IP_RANGES Lists allowed IP ranges for recipients.
RECIPIENT_TOKENS Lists tokens for recipients.
RECIPIENTS Describes recipients.
REFERENTIAL_CONSTRAINTS Describes referential (foreign key) constraints defined in the catalog.
ROUTINE_COLUMNS Describes result columns of table valued functions.
ROUTINE_PRIVILEGES Lists principals that have privileges on the routines in the catalog.
ROUTINES Describes routines (functions) in the catalog.
ROW_FILTERS Describes row filters on tables in the catalog.
SCHEMA_PRIVILEGES Lists principals that have privileges on the schemas in the catalog.
SCHEMA_TAGS Contains schema tagging metadata within the schema.
SCHEMA_SHARE_USAGE Describes the schemas referenced in shares.
SCHEMATA Describes schemas within the catalog.
SHARE_RECIPIENT_PRIVILEGES Describes the recipients granted access to shares.
SHARES Describes shares.
STORAGE_CREDENTIAL_PRIVILEGES [Deprecated] Lists principals that have privileges on the storage credentials.
STORAGE_CREDENTIALS [Deprecated] Describes storage credentials.
TABLE_CONSTRAINTS Describes metadata for all primary and foreign key constraints within the catalog.
TABLE_PRIVILEGES Lists principals that have privileges on the tables and views in the catalog.
TABLE_SHARE_USAGE Describes the tables referenced in shares.
TABLE_TAGS Contains table tagging metadata within a table.
TABLES Describes tables and views defined within the catalog.
VIEWS Describes view specific information about the views in the catalog.
VOLUMES Describes volumes defined in the catalog.
VOLUME_PRIVILEGES Lists principals that have privileges on the volumes in the catalog.
VOLUME_TAGS Contains volume tagging metadata applied to a volume.

Notes

While identifiers are case-insensitive when referenced in SQL statements, they are stored in the information schema as STRING. This implies that you must either search for them using the case in which the identifier is stored, or use functions such as ilike.

Examples

SQL 
> SELECT table_name, column_name
    FROM information_schema.columns
    WHERE data_type = 'DOUBLE'
      AND table_schema = 'information_schema';

The following are examples of workflows that use the system level information schema tables.

If you want to view all tables that have been created in the last 24 hours, your query could look like the following.

SQL 
> SELECT table_name, table_owner, created_by, last_altered, last_altered_by, table_catalog
    FROM system.information_schema.tables
    WHERE  datediff(now(), last_altered) < 1;

If you want to view how many tables you have in each schema, consider the following example.

SQL 
> SELECT table_schema, count(table_name)
    FROM system.information_schema.tables
    WHERE table_schema = 'tpch'
    GROUP BY table_schema
    ORDER BY 2 DESC