MySQL auto-store datetime for each row

Question

In MySQL, I'm 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.

Every time I INSERT or UPDATE the database, I will have to use the NOW() keyword. 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?

Digitiform

My poor grammar lurks on the dark depths of Stack Overflow. Thank you @Eric Leschinski. – Digitiform

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 CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP

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

Reference: TIMESTAMP properties

Swirl

ahh I didn't know you can use something like ON UPDATE CURRENT_TIMESTAMP – Digitiform

Aditional info: One TIMESTAMP column in a table can have the current timestamp as the default value for initializing the column, as the auto-update value, or both. It is not possible to have the current timestamp be the default value for one column and the auto-update value for another column. dev.mysql.com/doc/refman/5.0/en/timestamp-initialization.html – Elsyelton

DEFAULT ON UPDATE CURRENT_TIMESTAMP is not valid SQL. It must be either dt_modified datetime ON UPDATE CURRENT_TIMESTAMP or dt_modified datetime DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP If you still claim it is valid, then perhaps MySQL Workbench has a problem with it that should be mentioned. – Stenotypy

Answer 2

If you're using phpmyadmin you can do this by :

Imaret

Answer 3

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

should be the correct code.

Trompe

Answer 4

Well, you can't have both:

mysql doc:

It is not possible to have the current timestamp be the default value for one column and the auto-update value for another column.

Sad, isn't it?

You could however use null instead of now() following this tip

Fusilier

Answer 5

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.

Occasional

Answer 6

In phpmyadmin you can set

OR use this query

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

Busk

Answer 7

could be set as default an on update of rows

ALTER TABLE `tablename` CHANGE `dt` `dt` TIMESTAMP on update CURRENT_TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP;

Convulsion