SQL Server Automatic Update Datetimestamp Field

Need a datetime column in SQL Server that automatically updates when the record is modified

SQL Server doesn't have a way to define a default value for UPDATE.

So you need to add a column with default value for inserting:

ADD modstamp DATETIME2 NULL DEFAULT GETDATE()

And add a trigger on that table:

CREATE TRIGGER tgr_modstamp
ON **TABLENAME**
AFTER UPDATE AS
  UPDATE **TABLENAME**
  SET ModStamp = GETDATE()
  WHERE **ID** IN (SELECT DISTINCT **ID** FROM Inserted)

And yes, you need to specify a identity column for each trigger.

CAUTION: take care when inserting columns on tables where you don't know the code of the application. If your app have INSERT VALUES command without column definition, it will raise errors even with default value on new columns.

SQL Server : on update set current timestamp

Make a trigger on insert and update that updates the column with the current timestamp.

CREATE TRIGGER dbo.trgAfterUpdate ON dbo.YourTable
AFTER INSERT, UPDATE 
AS
  UPDATE dbo.YourTable
  SET last_changed = GETDATE()
  FROM Inserted i

To update a single row (which has been edited or inserted) you should use

CREATE TRIGGER dbo.trgAfterUpdate ON dbo.YourTable
AFTER INSERT, UPDATE 
AS
  UPDATE f set LastUpdate=GETDATE() 
  FROM 
  dbo.[YourTable] AS f 
  INNER JOIN inserted 
  AS i 
  ON f.rowID = i.rowID;

These should be all you need.

GETUTCDATE() if you want it in UTC

SQL Server knows the rows it processes

update myTable set last_time =CURRENT_TIMESTAMP ; worked, but it
updated all the rows instead of the current.

Yeah, guess what - because that is exactly what you tell SQL Server: Update all rows in the table.

Doesn't Sql Server know which is the actual record it is processing?

Sets have no current row ;) That is where the problem starts.

The only way to do that exactly as you want is up in my answer on the beginning: a timestamp.

When is a timestamp (auto) updated?

Give the command SHOW CREATE TABLE whatever

Then look at the table definition.

It probably has a line like this

logtime TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,

in it. DEFAULT CURRENT_TIMESTAMP means that any INSERT without an explicit time stamp setting uses the current time. Likewise, ON UPDATE CURRENT_TIMESTAMP means that any update without an explicit timestamp results in an update to the current timestamp value.

You can control this default behavior when creating your table.

Or, if the timestamp column wasn't created correctly in the first place, you can change it.

ALTER TABLE whatevertable
     CHANGE whatevercolumn 
            whatevercolumn TIMESTAMP NOT NULL
                           DEFAULT CURRENT_TIMESTAMP 
                           ON UPDATE CURRENT_TIMESTAMP;

This will cause both INSERT and UPDATE operations on the table automatically to update your timestamp column. If you want to update whatevertable without changing the timestamp, that is,

To prevent the column from updating when other columns change

then you need to issue this kind of update.

UPDATE whatevertable
   SET something = 'newvalue',
       whatevercolumn = whatevercolumn
 WHERE someindex = 'indexvalue'

This works with TIMESTAMP and DATETIME columns. (Prior to MySQL version 5.6.5 it only worked with TIMESTAMPs) When you use TIMESTAMPs, time zones are accounted for: on a correctly configured server machine, those values are always stored in UTC and translated to local time upon retrieval.

Auto update DATETIME column on insert with SQL?

It seems the issue was that the column needed to be a TIMESTAMP not DATETIME upon changing it, I was able to successfully add the CURRENT_TIMESTAMP argument.

SQL Server 2005 Auto Updated DateTime Column - LastUpdated

A default constraint only works on inserts; for an update use a trigger.

Making a DateTime field in a database automatic?

You need to set the "default value" for the date field to getdate(). Any records inserted into the table will automatically have the insertion date as their value for this field.

The location of the "default value" property is dependent on the version of SQL Server Express you are running, but it should be visible in the column properties tab if you select the date field of your table when editing the table.

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