Bug #17809 support for DEFAULT CURRENT_USER

• Submitted: 28 Feb 2006 22:24
• Modified: 10 Mar 2023 1:18
• Reporter: Peter Laursen (Basic Quality Contributor)
• Status: Closed
• Category: MySQL Server: DML
• Severity: S4 (Feature request)
• OS: Any (any)
• CPU Architecture: Any

[28 Feb 2006 22:24] Peter Laursen

Description:
This request could save people some coding in situations where they want to keep track of who created or who last changed a recored:

Enable fuctionalities with CURRENT_USER as exists with CURRENT_TIMESTAMP.

How to repeat:
alter table `test`.`dummy` change `creator` `creator` varchar (50)  DEFAULT current_user;

Error Code : 1064
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'current_user NOT NULL' at line 1
(0 ms taken)

Suggested fix:
implement support for 

DEFAULT CURRENT_USER

and even for 

DEFAULT CURRENT_USER on update CURRENT_USER

[5 Mar 2006 9:07] Valeriy Kravchuk

Thank you for a reasonable feature request. This feature will be available as soon as expressions will be allowed in DEFAULT clause.

[5 Mar 2006 9:30] Peter Laursen

Any idea when that will be ?

[10 Mar 2023 1:18] Jon Stephens

This enhancement is implemented in MySQL 8.0.34, described in the 8.0.34 changelog as follows:

    CURRENT_USER() can now be used as a default value for CHAR,
    VARCHAR, and TEXT columns in CREATE TABLE and ALTER TABLE ...
    ADD COLUMN statements. To insure that values having the maximum
    possible length can be stored, the column should be able to
    accommodate 288 characters (or more).

    The synonyms SESSION_USER() and USER() are also supported in all
    of the cases just mentioned. For example, the following sequence
    of statements now works similarly to what is shown here:

mysql> SELECT CURRENT_USER();
+-------------------+
| CURRENT_USER()    |
+-------------------+
|  sakila@localhost |
+-------------------+
1 row in set (0.00 sec)

mysql> CREATE TABLE t (
     >  c1 VARCHAR(288) DEFAULT (USER()), 
     >  c2 VARCHAR(288) DEFAULT (CURRENT_USER()), 
     >  c3 VARCHAR(288) DEFAULT (SESSION_USER())
     > );
Query OK, 0 rows affected (0.04 sec)

mysql> INSERT INTO t VALUES ROW();
Query OK, 1 row affected (0.01 sec)

mysql> TABLE t;
+-------------------+-------------------+-------------------+
| c1                | c2                | c3                |
+-------------------+-------------------+-------------------+
|  sakila@localhost |  sakila@localhost |  sakila@localhost |
+-------------------+-------------------+-------------------+
1 row in set (0.00 sec)

    When used in this way, these functions are also included in the
    output of SHOW CREATE TABLE and SHOW COLUMNS, and can be seen in
    the COLUMN_DEFAULT column of the Information Schema COLUMNS
    table.

Closed.