CockroachDB provides a virtual schema called information_schema that contains information about your database's tables, columns, indexes, and views. This information can be used for introspection and reflection.
The definition of information_schema is part of the SQL standard and can therefore be relied on to remain stable over time. This contrasts with CockroachDB's SHOW statements, which provide similar data and are meant to be stable in CockroachDB but not standardized. It also contrasts with the virtual schema crdb_internal, which reflects the internals of CockroachDB and may thus change across CockroachDB versions.
The information_schema views typically represent objects that the current user has privilege to access. To ensure you can view all the objects in a database, access it as the root user.
Data exposed by information_schema
To perform introspection on objects, you can either read from the related information_schema table or use one of CockroachDB's SHOW statements.
| Object | Information Schema Table | Corresponding SHOW Statement |
|---|---|---|
| Columns | columns |
SHOW COLUMNS |
| Constraints | key_column_usage, referential_constraints, table_constraints |
SHOW CONSTRAINTS |
| Databases | schemata |
SHOW DATABASE |
| Indexes | statistics |
SHOW INDEX |
| Privileges | schema_privileges, table_privileges |
SHOW GRANTS |
| Roles | role_table_grants |
SHOW ROLES |
| Sequences | sequences |
SHOW CREATE SEQUENCE |
| Tables | tables |
SHOW TABLES |
| Views | tables, views |
SHOW CREATE |
Tables in information_schema
The virtual schema information_schema contains virtual tables, also called "system views," representing the database's objects, each of which is detailed below.
These differ from regular SQL views in that they are not showing data created from the content of other tables. Instead, CockroachDB generates the data for virtual tables when they are accessed.
Currently, there are some information_schema tables that are empty but provided for compatibility:
routinesparameters
A query can specify a table name without a database name (e.g., SELECT * FROM information_schema.sequences). See Name Resolution for more information.
administrable_role_authorizations
administrable_role_authorizations identifies all roles that the current user has the admin option for.
| Column | Description |
|---|---|
grantee |
The name of the user to which this role membership was granted (always the current user). |
applicable_roles
applicable_roles identifies all roles whose privileges the current user can use. This implies there is a chain of role grants from the current user to the role in question. The current user itself is also an applicable role, but is not listed.
| Column | Description |
|---|---|
grantee |
Name of the user to which this role membership was granted (always the current user). |
role_name |
Name of a role. |
is_grantable |
YES if the grantee has the admin option on the role; NO if not. |
columns
columns contains information about the columns in each table.
| Column | Description |
|---|---|
table_catalog |
Name of the database containing the table. |
table_schema |
Name of the schema containing the table. |
table_name |
Name of the table. |
column_name |
Name of the column. |
ordinal_position |
Ordinal position of the column in the table (begins at 1). |
column_default |
Default value for the column. |
is_nullable |
YES if the column accepts NULL values; NO if it doesn't (e.g., it has the NOT NULL constraint). |
data_type |
Data type of the column. |
character_maximum_length |
If data_type is STRING, the maximum length in characters of a value; otherwise NULL. |
character_octet_length |
If data_type is STRING, the maximum length in octets (bytes) of a value; otherwise NULL. |
numeric_precision |
If data_type is numeric, the declared or implicit precision (i.e., number of significant digits); otherwise NULL. |
numeric_precision_radix |
If data_type identifies a numeric type, the base in which the values in the columns numeric_precision and numeric_scale are expressed (either 2 or 10). For all other data types, column is NULL. |
numeric_scale |
If data_type is an exact numeric type, the scale (i.e., number of digits to the right of the decimal point); otherwise NULL. |
datetime_precision |
Always NULL (unsupported by CockroachDB). |
character_set_catalog |
Always NULL (unsupported by CockroachDB). |
character_set_schema |
Always NULL (unsupported by CockroachDB). |
character_set_name |
Always NULL (unsupported by CockroachDB). |
generation_expression |
The expression used for computing the column value in a computed column. |
column_privileges
column_privileges identifies all privileges granted on columns to or by a currently enabled role. There is one row for each combination of grantor, grantee, and column (defined by table_catalog, table_schema, table_name, and column_name).
| Column | Description |
|---|---|
grantor |
Name of the role that granted the privilege. |
grantee |
Name of the role that was granted the privilege. |
table_catalog |
Name of the database containing the table that contains the column (always the current database). |
table_schema |
Name of the schema containing the table that contains the column. |
table_name |
Name of the table. |
column_name |
Name of the column. |
privilege_type |
Name of the privilege. |
is_grantable |
Always NULL (unsupported by CockroachDB). |
constraint_column_usage
constraint_column_usage identifies all columns in a database that are used by some constraint.
| Column | Description |
|---|---|
table_catalog |
Name of the database that contains the table that contains the column that is used by some constraint. |
table_schema |
Name of the schema that contains the table that contains the column that is used by some constraint. |
table_name |
Name of the table that contains the column that is used by some constraint. |
column_name |
Name of the column that is used by some constraint. |
constraint_catalog |
Name of the database that contains the constraint. |
constraint_schema |
Name of the schema that contains the constraint. |
constraint_name |
Name of the constraint. |
enabled_roles
The enabled_roles view identifies enabled roles for the current user. This includes both direct and indirect roles.
| Column | Description |
|---|---|
role_name |
Name of a role. |
key_column_usage
key_column_usage identifies columns with PRIMARY KEY, UNIQUE, or foreign key / REFERENCES constraints.
| Column | Description |
|---|---|
constraint_catalog |
Name of the database containing the constraint. |
constraint_schema |
Name of the schema containing the constraint. |
constraint_name |
Name of the constraint. |
table_catalog |
Name of the database containing the constrained table. |
table_schema |
Name of the schema containing the constrained table. |
table_name |
Name of the constrained table. |
column_name |
Name of the constrained column. |
ordinal_position |
Ordinal position of the column within the constraint (begins at 1). |
position_in_unique_constraint |
For foreign key constraints, ordinal position of the referenced column within its uniqueness constraint (begins at 1). |
referential_constraints
referential_constraints identifies all referential (Foreign Key) constraints.
| Column | Description |
|---|---|
constraint_catalog |
Name of the database containing the constraint. |
constraint_schema |
Name of the schema containing the constraint. |
constraint_name |
Name of the constraint. |
unique_constraint_catalog |
Name of the database containing the UNIQUE or PRIMARY KEY constraint that the foreign key constraint references (always the current database). |
unique_constraint_schema |
Name of the schema containing the UNIQUE or PRIMARY KEY constraint that the foreign key constraint references. |
unique_constraint_name |
Name of the UNIQUE or PRIMARY KEY constraint. |
match_option |
Match option of the foreign key constraint: FULL, PARTIAL, or NONE. |
update_rule |
Update rule of the foreign key constraint: CASCADE, SET NULL, SET DEFAULT, RESTRICT, or NO ACTION. |
delete_rule |
Delete rule of the foreign key constraint: CASCADE, SET NULL, SET DEFAULT, RESTRICT, or NO ACTION. |
table_name |
Name of the table containing the constraint. |
referenced_table_name |
Name of the table containing the UNIQUE or PRIMARY KEY constraint that the foreign key constraint references. |
role_table_grants
role_table_grants identifies which privileges have been granted on tables or views where the grantor
or grantee is a currently enabled role. This table is identical to table_privileges.
| Column | Description |
|---|---|
grantor |
Name of the role that granted the privilege. |
grantee |
Name of the role that was granted the privilege. |
table_catalog |
Name of the database containing the table. |
table_schema |
Name of the schema containing the table. |
table_name |
Name of the table. |
privilege_type |
Name of the privilege. |
is_grantable |
Always NULL (unsupported by CockroachDB). |
with_hierarchy |
Always NULL (unsupported by CockroachDB). |
schema_privileges
schema_privileges identifies which privileges have been granted to each user at the database level.
| Column | Description |
|---|---|
grantee |
Username of user with grant. |
table_catalog |
Name of the database containing the constrained table. |
table_schema |
Name of the schema containing the constrained table. |
privilege_type |
Name of the privilege. |
is_grantable |
Always NULL (unsupported by CockroachDB). |
schemata
schemata identifies the database's schemas.
| Column | Description |
|---|---|
table_catalog |
Name of the database. |
table_schema |
Name of the schema. |
default_character_set_name |
Always NULL (unsupported by CockroachDB). |
sql_path |
Always NULL (unsupported by CockroachDB). |
sequences
sequences identifies sequences defined in a database.
| Column | Description |
|---|---|
sequence_catalog |
Name of the database that contains the sequence. |
sequence_schema |
Name of the schema that contains the sequence. |
sequence_name |
Name of the sequence. |
data_type |
The data type of the sequence. |
numeric_precision |
The (declared or implicit) precision of the sequence data_type. |
numeric_precision_radix |
The base of the values in which the columns numeric_precision and numeric_scale are expressed. The value is either 2 or 10. |
numeric_scale |
The (declared or implicit) scale of the sequence data_type. The scale indicates the number of significant digits to the right of the decimal point. It can be expressed in decimal (base 10) or binary (base 2) terms, as specified in the column numeric_precision_radix. |
start_value |
The first value of the sequence. |
minimum_value |
The minimum value of the sequence. |
maximum_value |
The maximum value of the sequence. |
increment |
The value by which the sequence is incremented. A negative number creates a descending sequence. A positive number creates an ascending sequence. |
cycle_option |
Currently, all sequences are set to NO CYCLE and the sequence will not wrap. |
statistics
statistics identifies table indexes.
| Column | Description |
|---|---|
table_catalog |
Name of the database that contains the constrained table. |
table_schema |
Name of the schema that contains the constrained table. |
table_name |
Name of the table. |
non_unique |
NO if the index was created with the UNIQUE constraint; YES if the index was not created with UNIQUE. |
index_schema |
Name of the database that contains the index. |
index_name |
Name of the index. |
seq_in_index |
Ordinal position of the column within the index (begins at 1). |
column_name |
Name of the column being indexed. |
collation |
Always NULL (unsupported by CockroachDB). |
cardinality |
Always NULL (unsupported by CockroachDB). |
direction |
ASC (ascending) or DESC (descending) order. |
storing |
YES if column is stored; NO if it's indexed or implicit. |
implicit |
YES if column is implicit (i.e., it is not specified in the index and not stored); NO if it's indexed or stored. |
table_constraints
table_constraints identifies constraints applied to tables.
| Column | Description |
|---|---|
constraint_catalog |
Name of the database containing the constraint. |
constraint_schema |
Name of the schema containing the constraint. |
constraint_name |
Name of the constraint. |
table_catalog |
Name of the database containing the constrained table. |
table_schema |
Name of the schema containing the constrained table. |
table_name |
Name of the constrained table. |
constraint_type |
Type of constraint: CHECK, foreign key, PRIMARY KEY, or UNIQUE. |
is_deferrable |
YES if the constraint can be deferred; NO if not. |
initially_deferred |
YES if the constraint is deferrable and initially deferred; NO if not. |
table_privileges
table_privileges identifies which privileges have been granted to each user at the table level.
| Column | Description |
|---|---|
grantor |
Always NULL (unsupported by CockroachDB). |
grantee |
Username of the user with grant. |
table_catalog |
Name of the database that the grant applies to. |
table_schema |
Name of the schema that the grant applies to. |
table_name |
Name of the table that the grant applies to. |
privilege_type |
Type of privilege: SELECT, INSERT, UPDATE, DELETE, TRUNCATE, REFERENCES, or TRIGGER. |
is_grantable |
Always NULL (unsupported by CockroachDB). |
with_hierarchy |
Always NULL (unsupported by CockroachDB). |
tables
tables identifies tables and views in the database.
| Column | Description |
|---|---|
table_catalog |
Name of the database that contains the table. |
table_schema |
Name of the schema that contains the table. |
table_name |
Name of the table. |
table_type |
Type of the table: BASE TABLE for a normal table, VIEW for a view, or SYSTEM VIEW for a view created by CockroachDB. |
version |
Version number of the table; versions begin at 1 and are incremented each time an ALTER TABLE statement is issued on the table. Note that this column is an experimental feature used for internal purposes inside CockroachDB and its definition is subject to change without notice. |
user_privileges
user_privileges identifies global privileges.
root users. Therefore, this view contains global privileges only for root.
| Column | Description |
|---|---|
grantee |
Username of user with grant. |
table_catalog |
Name of the database that the privilege applies to. |
privilege_type |
Type of privilege. |
is_grantable |
Always NULL (unsupported by CockroachDB). |
views
views identifies views in the database.
| Column | Description |
|---|---|
table_catalog |
Name of the database that contains the view. |
table_schema |
Name of the schema that contains the view. |
table_name |
Name of the view. |
view_definition |
AS clause used to create the view. |
check_option |
Always NULL (unsupported by CockroachDB). |
is_updatable |
Always NULL (unsupported by CockroachDB). |
is_insertable_into |
Always NULL (unsupported by CockroachDB). |
is_trigger_updatable |
Always NULL (unsupported by CockroachDB). |
is_trigger_deletable |
Always NULL (unsupported by CockroachDB). |
is_trigger_insertable_into |
Always NULL (unsupported by CockroachDB). |
Examples
Retrieve all columns from an information schema table
> SELECT * FROM db_name.information_schema.table_constraints;
+--------------------+-------------------+-----------------+---------------+--------------+-------------+-----------------+---------------+--------------------+
| constraint_catalog | constraint_schema | constraint_name | table_catalog | table_schema | table_name | constraint_type | is_deferrable | initially_deferred |
+--------------------+-------------------+-----------------+---------------+--------------+-------------+-----------------+---------------+--------------------+
| jsonb_test | public | primary | jsonb_test | public | programming | PRIMARY KEY | NO | NO |
+--------------------+-------------------+-----------------+---------------+--------------+-------------+-----------------+---------------+--------------------+
Retrieve specific columns from an information schema table
> SELECT table_name, constraint_name FROM db_name.information_schema.table_constraints;
+-------------+-----------------+
| table_name | constraint_name |
+-------------+-----------------+
| programming | primary |
+-------------+-----------------+
See also
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