Greetings!
Is there a silent specification change that can cause 'autoincrement'
to be dropped for a table? I seem to have lost 'autoincrement' (and
all the keys) on all 5 tables that use it, but I might have made a
change to all 5 tables and not inserted anything into them so I didn't
notice the change. table type MyISAM, mysql version 4.1.14-max

I track changes to my tables in a text file, and this is the 'evolved'
table deff. It works fine: show index is correct and autoincrement
exists in describe:

create table questions_temp (
content blob default "" NOT NULL,
answer_type set ("single","multiple","ordered") default "single" NOT
NULL,
correct_answer CHAR(16) default "" NOT NULL,
question_factor TINYINT default 1 NOT NULL,
previous_question_id SMALLINT UNSIGNED default 0 NOT NULL,
event_id SMALLINT UNSIGNED default 0 NOT NULL,
question_id SMALLINT UNSIGNED AUTO_INCREMENT NOT NULL,
KEY event_key (event_id),
KEY question_key (question_id));


However, show create shows this:
questions | CREATE TABLE `questions` (
`content` blob NOT NULL,
`answer_type` set('single','multiple','ordered') NOT NULL default
'single',
`correct_answer` varchar(16) NOT NULL default '',
`question_factor` tinyint(4) NOT NULL default '1',
`previous_question_id` smallint(5) unsigned NOT NULL default '0',
`event_id` smallint(5) unsigned NOT NULL default '0',
`question_id` smallint(5) unsigned NOT NULL default '0'
) ENGINE=MyISAM DEFAULT CHARSET=latin1

and describe shows this:
+----------------------+------------------------------------+------
+-----+---------+-------+
| Field | Type | Null |
Key | Default | Extra |
+----------------------+------------------------------------+------
+-----+---------+-------+
| content | blob |
| | | |
| answer_type | set('single','multiple','ordered') |
| | single | |
| correct_answer | varchar(16) |
| | | |
| question_factor | tinyint(4) |
| | 1 | |
| previous_question_id | smallint(5) unsigned |
| | 0 | |
| event_id | smallint(5) unsigned |
| | 0 | |
| question_id | smallint(5) unsigned |
| | 0 | |
+----------------------+------------------------------------+------
+-----+---------+-------+


no keys, no autoincrement.

I was able to fix the tables with:
alter table questions modify column question_id SMALLINT UNSIGNED
AUTO_INCREMENT NOT NULL KEY;
(note the addition of "KEY' at the end)
and
alter table questions add index event_key (event_id);
but I would like to know what I did so I don't do it again *wink*

Thanx!