LAST USER can be used as a default value in columns with character data types.
On INSERT, this constant has the same effect as CURRENT USER.
On UPDATE, if a column with a default value of LAST USER is not explicitly modified, it is changed to the name of the current
user.
When combined with the DEFAULT TIMESTAMP, a default value of LAST USER can be used to record (in separate columns) both the
user and the date and time of day a row was last changed.