Question

There are some other questions where people have problems with timestamp being all zeros. I have checked them and this is not a duplicate.

I declare a table like this:

CREATE TABLE  `my_db`.`my_table` (
  `time_stamp` timestamp NOT NULL,
  `author` varchar() NOT NULL,
  `text` text NOT NULL,
  `md5` int(11) NOT NULL,
  PRIMARY KEY (`time_stamp`)
) ;

I also have a second table which will have a timestamp as primary key and they should have the same value.

Coding in Delphi, I use SELECT CURRENT_TIMESTAMP which returns something like '19/6/2010 4:56:17 AM' which I then use in an INSERT statement. The INSERT succeeds, but the timestamp is all zeros.

What am I doing wrong?

Here’s the INSERT code:

  sqlCommand := 'INSERT INTO my_db.my_table(time_stamp, author, text, md5) VALUES ("' 
                   + timestamp + 
                    '", "mawg", ' +
                    '"Hello, world"' +
                    0 +
                    '");';
  Result := DoSQlCommandWithNoResultSet(sqlCommand, AdoConnection);

Insertion will be extremely low rate, one entry every few weeks or maybe months, so I am happy with timestamp as primary key. I am keeping “versions” of things, so timestamp makes sense to me.

I am begging to think that this is an ADO problem, although I would expect ADO to just “pass through”. I don’t see any other solution. In a console, the output is “correct”, but when run through ADO in Delphi then it is wrong

Can I specify to MySQL how it ought to format its dates?

Answer 1

After reviewing the MySQL documentation, it appears that if your timestamp value is incorrectly formatted, it would normally cause the timestamp to be '0000-00-00 00:00:00'.
In any case, you don’t need to specify a timestamp value—that’s the benefit of TIMESTAMP over DATETIME. And even if you did, you can simply set it to NOW() instead of running an unnecessary SELECT statement.

Edit:

Also, I know you said you thought this through, but have you considered daylight savings time? This could cause two records to have the same timestamp when the clock is set back during autumn.

Edit 2:

K, I don’t know why I didn’t catch this earlier, but that timestamp format you gave is incorrect. Try inserting a valid timestamp like '2010/06/19 4:56:17'. MySQL has pretty relaxed parsing of date & time values, but it always has to be year-month-date and hour-minute-seconds.

Edit 3:

Alright, there seems to be a little confusion over this, so I’m gonna post this quote from the MySQL 5.0 doc page on the DATETIME format:

For values specified as strings that include date part delimiters, it is not necessary to specify two digits for month or day values that are less than 10. ‘1979-6-9’ is the same as ‘1979-06-09’. Similarly, for values specified as strings that include time part delimiters, it is not necessary to specify two digits for hour, minute, or second values that are less than 10. ‘1979-10-30 1:2:3’ is the same as ‘1979-10-30 01:02:03’.