TABLE_CONSTRAINTS view

The TABLE_CONSTRAINTS view contains the primary and foreign key relations in a BigQuery dataset.

Required permissions

You need the following Identity and Access Management (IAM) permissions :

bigquery.tables.get for viewing primary and foreign key definitions.
bigquery.tables.list for viewing table information schemas.

Each of the following predefined roles has the needed permissions to perform the workflows detailed in this document:

roles/bigquery.dataEditor
roles/bigquery.dataOwner
roles/bigquery.admin

For more information about IAM roles and permissions in BigQuery, see Predefined roles and permissions .

Schema

The INFORMATION_SCHEMA.TABLE_CONSTRAINTS view has the following schema:

Column Name	Type	Meaning
`CONSTRAINT_CATALOG`	`STRING`	The constraint project name.
`CONSTRAINT_SCHEMA`	`STRING`	The constraint dataset name.
`CONSTRAINT_NAME`	`STRING`	The constraint name.
`TABLE_CATALOG`	`STRING`	The constrained table project name.
`TABLE_SCHEMA`	`STRING`	The constrained table dataset name.
`TABLE_NAME`	`STRING`	The constrained table name.
`CONSTRAINT_TYPE`	`STRING`	Either `PRIMARY KEY` or `FOREIGN KEY` .
`IS_DEFERRABLE`	`STRING`	`YES` or `NO` depending on if a constraint is deferrable. Only `NO` is supported.
`INITIALLY_DEFERRED`	`STRING`	Only `NO` is supported.
`ENFORCED`	`STRING`	`YES` or `NO` depending on if the constraint is enforced. Only `NO` is supported.

Scope and syntax

Queries against this view must include a dataset qualifier. For queries with a dataset qualifier, you must have permissions for the dataset. For more information see Syntax . The following table shows the region and resource scopes for this view:

View name	Resource scope	Region scope
`[ PROJECT_ID .] DATASET .INFORMATION_SCHEMA.TABLE_CONSTRAINTS;`	Dataset level	Dataset location

Replace the following:

Optional: PROJECT_ID : the ID of your Google Cloud project. If not specified, the default project is used.

Examples

The following query shows the constraints for a single table in a dataset:

 SELECT 
  
 * 
 FROM 
  
  PROJECT_ID 
 
 . 
  DATASET 
 
 . 
 INFORMATION_SCHEMA 
 . 
 TABLE_CONSTRAINTS 
 WHERE 
  
 table_name 
  
 = 
  
  TABLE 
 
 ;

Replace the following:

PROJECT_ID : Optional. The name of your cloud project. If not specified, this command uses the default project.
DATASET : The name of your dataset.
TABLE : The name of the table.

Conversely, the following query shows the constraints for all tables in a single dataset.

 SELECT 
  
 * 
 FROM 
  
  PROJECT_ID 
 
 . 
  DATASET 
 
 . 
 INFORMATION_SCHEMA 
 . 
 TABLE_CONSTRAINTS 
 ;

With existing constraints, the query results are similar to the following:

+-----+---------------------+-------------------+-----------------------+---------------------+--------------+------------+-----------------+---------------+--------------------+----------+
| Row | constraint_catalog  | constraint_schema |    constraint_name    |    table_catalog    | table_schema | table_name | constraint_type | is_deferrable | initially_deferred | enforced |
+-----+---------------------+-------------------+-----------------------+---------------------+--------------+------------+-----------------+---------------+--------------------+----------+
|   1 | myConstraintCatalog | myDataset         | orders.pk$            | myConstraintCatalog | myDataset    | orders     | PRIMARY KEY     | NO            | NO                 | NO       |
|   2 | myConstraintCatalog | myDataset         | orders.order_customer | myConstraintCatalog | myDataset    | orders     | FOREIGN KEY     | NO            | NO                 | NO       |
+-----+---------------------+-------------------+-----------------------+---------------------+--------------+------------+-----------------+---------------+--------------------+----------+

If the table or dataset has no constraints, the query results look like this:

+-----------------------------+
| There is no data to display |
+-----------------------------+