TABLE_CONSTRAINTS view¶

This Information Schema view displays a row for each table constraint that is defined in the specified (or current) database. This view returns information about the following constraint types:

PRIMARY KEY
FOREIGN KEY
UNIQUE

For general information about constraints, see Constraints.

See also:: REFERENTIAL_CONSTRAINTS view

Columns¶

Column Name	Data Type	Description
CONSTRAINT_CATALOG	TEXT	Database that the constraint belongs to
CONSTRAINT_SCHEMA	TEXT	Schema that the constraint belongs to
CONSTRAINT_NAME	TEXT	Name of the constraint
TABLE_CATALOG	TEXT	Name of the database of the current table
TABLE_SCHEMA	TEXT	Name of the schema of the current table
TABLE_NAME	TEXT	Name of the current table
CONSTRAINT_TYPE	TEXT	Type of the constraint
IS_DEFERRABLE	TEXT	Whether evaluation of the constraint can be deferred
INITIALLY_DEFERRED	TEXT	Whether evaluation of the constraint is deferrable and initially deferred
ENFORCED	TEXT	Whether the constraint is enforced
COMMENT	TEXT	Comment for this constraint
CREATED	TIMESTAMP_LTZ	Creation time of the constraint
LAST_ALTERED	TIMESTAMP_LTZ	Date and time the object was last altered by a DML, DDL, or background metadata operation. See Usage Notes.
RELY	TEXT	Whether a constraint in NOVALIDATE mode is taken into account during query rewrite. For details, see Constraint properties.

Usage notes¶

The view only displays objects for which the current role for the session has been granted access privileges.
The LAST_ALTERED column is updated when the following operations are performed on an object:
- DDL operations.
- DML operations (for tables only). This column is updated even when no rows are affected by the DML statement.
- Background maintenance operations on metadata performed by Snowflake.

Example¶

Create a hybrid table with a multi-column PRIMARY KEY constraint and a comment on the constraint. Query the view to get information about the constraint.

CREATE OR REPLACE HYBRID TABLE HT2PK
  (col1 NUMBER(38,0) NOT NULL,
  col2 NUMBER(38,0) NOT NULL,
  col3 VARCHAR(16777216),
  CONSTRAINT PKEY_2 PRIMARY KEY (col1, col2) COMMENT 'Primary key on two columns');

SELECT constraint_name, table_name, constraint_type, enforced, comment
  FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
  WHERE COMMENT IS NOT NULL;

Copy

+-----------------+------------+-----------------+----------+----------------------------+
| CONSTRAINT_NAME | TABLE_NAME | CONSTRAINT_TYPE | ENFORCED | COMMENT                    |
|-----------------+------------+-----------------+----------+----------------------------|
| PKEY_2          | HT2PK      | PRIMARY KEY     | YES      | Primary key on two columns |
+-----------------+------------+-----------------+----------+----------------------------+

Return a list of constraints on all tables that have names beginning with HT:

SELECT constraint_name, table_name, constraint_type, enforced, comment
  FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
  WHERE table_name LIKE 'HT%'
  ORDER BY table_name;

Copy

+-----------------------------------------------------+------------------------+-----------------+----------+----------------------------+
| CONSTRAINT_NAME                                     | TABLE_NAME             | CONSTRAINT_TYPE | ENFORCED | COMMENT                    |
|-----------------------------------------------------+------------------------+-----------------+----------+----------------------------|
| SYS_CONSTRAINT_da2e8533-5501-4862-ae42-0a7798d578eb | HT01                   | PRIMARY KEY     | YES      | NULL                       |
| SYS_CONSTRAINT_5b3c6d13-f607-4ef6-a147-0026bae98c71 | HT1                    | PRIMARY KEY     | YES      | NULL                       |
| SYS_CONSTRAINT_d5887706-0e3b-4d5b-8787-e3327cdf4851 | HT100                  | PRIMARY KEY     | YES      | NULL                       |
| PK1                                                 | HT1PK                  | PRIMARY KEY     | YES      | NULL                       |
| SYS_CONSTRAINT_f1d1e153-cc32-477c-9a24-5c049e40ca0a | HT239                  | PRIMARY KEY     | YES      | NULL                       |
| SYS_CONSTRAINT_fe27c4f3-23f6-4091-92c4-5acd53cc5029 | HT239                  | UNIQUE          | YES      | NULL                       |
| PKEY_2                                              | HT2PK                  | PRIMARY KEY     | YES      | Primary key on two columns |
| SYS_CONSTRAINT_0bd41d0f-11f7-4366-82a3-f03f31fcce7e | HT616                  | PRIMARY KEY     | YES      | NULL                       |
| SYS_CONSTRAINT_6124310b-5f50-4009-a5c0-dc1b5a89b0bc | HT616                  | UNIQUE          | YES      | NULL                       |
| SYS_CONSTRAINT_bf3d76ba-de1e-4227-954f-9f53de777ed4 | HT619                  | PRIMARY KEY     | YES      | NULL                       |
| SYS_CONSTRAINT_c97bfe9b-6098-4b8a-b796-e341071db72a | HT619                  | FOREIGN KEY     | YES      | NULL                       |
| SYS_CONSTRAINT_6e02d776-1759-449e-aece-467aaaefcfc8 | HTFK                   | PRIMARY KEY     | YES      | NULL                       |
| SYS_CONSTRAINT_51118aaf-1ee6-4548-bc9a-f87e65d92528 | HTFK                   | FOREIGN KEY     | YES      | NULL                       |
| SYS_CONSTRAINT_fe27c4f3-23f6-4091-92c4-5acd53cc5029 | HTLIKE                 | UNIQUE          | YES      | NULL                       |
| SYS_CONSTRAINT_f1d1e153-cc32-477c-9a24-5c049e40ca0a | HTLIKE                 | PRIMARY KEY     | YES      | NULL                       |
| SYS_CONSTRAINT_aad16788-491a-4e68-b0e3-30d48a33a1c1 | HTPK                   | PRIMARY KEY     | YES      | NULL                       |
| SYS_CONSTRAINT_0bdff17e-e90a-4929-99c5-98e3597e3069 | HTT1                   | PRIMARY KEY     | YES      | NULL                       |
| SYS_CONSTRAINT_39e9110f-7a72-454e-bfe2-0a26eca97e7c | HT_PRECIP              | PRIMARY KEY     | YES      | NULL                       |
| SYS_CONSTRAINT_6acd8274-04e7-4b22-b9ae-29185b979219 | HT_SENSOR_DATA_DEVICE1 | PRIMARY KEY     | YES      | NULL                       |
| SYS_CONSTRAINT_39e9110f-7a72-454e-bfe2-0a26eca97e7c | HT_WEATHER             | PRIMARY KEY     | YES      | NULL                       |
| SYS_CONSTRAINT_843d828a-900d-409e-a57d-8f27b602eccf | HT_WEATHER             | PRIMARY KEY     | YES      | NULL                       |
+-----------------------------------------------------+------------------------+-----------------+----------+----------------------------+