MySQL auto-store datetime for each row

Question

Lately I've been doing quite a few projects that require the use of back-end, including MySQL.

However I'm quite sick of adding the columns dt_created and dt_modified (which are date time stamps for creation and last modified respectively) to all the tables I have in my database.

Everytime I INSERT or UPDATE the database, I will have to use NOW() where appropriately. This is going all over my persistence.

Is there any efficient alternative where MySQL can automatically store at least the datatime of the row that is inserted and let me retrieve it?

Answer 1

You can use DEFAULT constraints to set the timestamp:

ALTER TABLE
 MODIFY dt_created datetime DEFAULT CURRENT_TIMESTAMP

ALTER TABLE
 MODIFY dt_modified datetime DEFAULT ON UPDATE CURRENT_TIMESTAMP

Then you wouldn't have to specify NOW() in your INSERT/UPDATE statements.

Reference: TIMESTAMP properties

Answer 2

Similar question was asked here "Timestamp for MySQL" the timestamp field will update every time it is accessed. You might also consider a Trigger placed on the table in question to automatically populate those fields for you. Depending on the environment some shops/businesses do not like the use of triggers and so you might have to find alternate work arounds.

Answer 3

ALTER TABLE  `tablename` CHANGE  `dt`  `dt` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP

should be the correct code.