Feedback: ADD CONSTRAINT does not document IF NOT EXISTS

[hand-crdb]

Steven Hand (hand-crdb) commented:

Page: https://cockroachlabs.com/docs/v22.2/add-constraint.html

What is the reason for your feedback?

[ ] Missing the information I need

[ ] Too complicated

[ X] Out of date

[ ] Something is broken

[ ] Other

Additional details

CockroachDB appears to support IF NOT EXISTS in ALTER TABLE ADD CONSTRAINT but this is not documented. See GitHub issue #53007 and the example below:

> create table a (pk integer primary key, p integer, d integer, q integer);
CREATE TABLE

> ALTER TABLE a ADD CONSTRAINT c UNIQUE (p);
ALTER TABLE

> ALTER TABLE a ADD CONSTRAINT c UNIQUE (p);
ERROR: constraint with name "c" already exists
SQLSTATE: 42710

> ALTER TABLE a ADD CONSTRAINT if not exists c UNIQUE (p);
ALTER TABLE

> ALTER TABLE a ADD CONSTRAINT if not exists d UNIQUE (d);
ALTER TABLE

> show create table a;
  table_name |              create_statement
-------------+----------------------------------------------
  a          | CREATE TABLE public.a (
             |     pk INT8 NOT NULL,
             |     p INT8 NULL,
             |     d INT8 NULL,
             |     q INT8 NULL,
             |     CONSTRAINT a_pkey PRIMARY KEY (pk ASC),
             |     UNIQUE INDEX c (p ASC),
             |     UNIQUE INDEX d (d ASC)
             | )
(1 row)

The above example is from v22.1.13.

Jira Issue: DOC-6648

[exalate-issue-sync]

Lauren Hirata Singh (lnhsingh) commented:
Ryan Kuo - is this update covered by your SQL docs cleanup?

[exalate-issue-sync]

Ryan Kuo (taroface) commented:
Lauren Hirata Singh Steven Hand This was indeed covered in the SQL docs reorg - {{IF NOT EXISTS}} is found in the {{ALTER TABLE}} SQL diagram and parameters table for {{ADD CONSTRAINT}}.

https://www.cockroachlabs.com/docs/stable/alter-table.html#add-constraint

I’ll close the issue.