Information schema

The information schema consists of a set of views that contain information about the objects defined in the current database.

Tables

The information_schema.tables view contains all tables, views, sinks, and materialized views defined in the current database.

NOTE

Materialized views are specific to the information schema of RisingWave. They are not included in the information schema of PostgreSQL.

The information_schema.tables view contains the following columns.

Column	Type	Description
table_catalog	varchar	Name of the current database.
table_schema	varchar	Name of the schema that contains the table, view, or materialized view. The default schema for user-created objects is public.
table_name	varchar	Name of the table, view, or materialized view.
table_type	varchar	Type of the table, view, or materialized view. BASE TABLE for a user-defined table, VIEW for a non-materialized view, MATERIALIZED VIEW for a materialized view, and SYSTEM TABLE for a system table.
is_insertable_into	varchar	YES if the table or view is insertable into, NO if not. User-defined tables are always insertable, while views and materialized views are not necessarily.

Table constraints

The table_constraints view contains all constraints for tables that the current user owns or has privileges other than SELECT on.

The table_constraints view contains the following columns.

Column	Type	Description
constraint_catalog	varchar	Name of the database that contains the constraint.
constraint_schema	varchar	Name of the schema that contains the constraint.
constraint_name	varchar	Name of the constraint.
table_catalog	varchar	Name of the database that contains the table.
table_schema	varchar	Name of the schema that contains the table.
table_name	varchar	Name of the table.
constraint_type	varchar	Type of the constraint: PRIMARY KEY(p), UNIQUE(u), CHECK(c), or EXCLUDE(x).
is_deferrable	varchar	YES if the constraint is deferrable, NO if not.
initially_deferred	varchar	YES if the constraint is deferrable and initially deferred, NO if not.
enforced	varchar	YES if the constraint is validated and enforced, NO if not.

TEMPORARY LIMITATION

This view assumes the constraint schema is the same as the table schema, since pg_catalog.pg_constraint only supports primary key.

Schemata

The schemata view contains all accessible schemas in the current database for users, either by way of being the owner or having some privilege.

It contains the following columns.

Column	Type	Description
catalog_name	varchar	Name of the database containing the schema.
schema_name	varchar	Name of the schema.
schema_owner	varchar	Name of the schema owner.
default_character_set_catalog	varchar	Name of the database that contains the schema’s default character set.
default_character_set_schema	varchar	Name of the schema containing the default character set.
default_character_set_name	varchar	Name of the schema’s default character set.
sql_path	varchar	SQL path specification for the schema.

Views

The information_schema.views view contains information about the views in the database.

It contains the following columns.

Column	Type	Description
table_catalog	varchar	Name of the current database.
table_schema	varchar	Name of the schema that contains the view.
table_name	varchar	Name of the view.
view_definition	varchar	SQL statement that defines the view.

TEMPORARY LIMITATION

Users with access to information_schema.views can potentially access all views, which poses a security risk. We are working to resolve this limitation. Once the fix is implemented, this message will be removed.

Columns

The information_schema.columns view contains information about columns of all tables, views, and materialized views in the database.

Column	Type	Description
table_catalog	varchar	Name of the current database.
table_schema	varchar	Name of the schema that contains the table, sink, view, or materialized view. The default schema for user-created objects is public.
table_name	varchar	Name of the table, sink, view, or materialized view
column_name	varchar	Name of the column
ordinal_position	int32	Ordinal position of the column within the table (count starts at 1)
is_nullable	varchar	YES if the column is possibly nullable; NO if it is known not nullable.
data_type	varchar	Data type of the column
is_generated	varchar	ALWAYS if the column has a generated value; NEVER if it doesn’t.
generation_expression	varchar	Expression for generating values when is_generated is ALWAYS.

How to use the information schema views?

You can use various information schema views to determine the makeup of tables, sinks, views, and materialized views in a database.

For example, you can query for names and types of all the tables, views, and materialized views in the current database:

SELECT table_name, table_type
FROM information_schema.tables;

To query for all of the columns in a table, sink, view, or materialized view called taxi_trip:

SELECT column_name
FROM information_schema.columns
WHERE table_name='taxi_trip';

To find out tables, sinks, views, and materialized views that contain a column called trip_id:

SELECT table_name
FROM information_schema.columns
WHERE column_name='trip_id';