The timestamp user-defined datatype is necessary for columns in tables that are to be browsed in Open Client™ DB-Library applications.
Every time a row containing a timestamp column is inserted or updated, the timestamp column is automatically updated. A table can have only one column of the timestamp datatype. A column named timestamp automatically has the system datatype timestamp. Its definition is:
varbinary(8) "NULL"
Because timestamp is a user-defined datatype, you cannot use it to define other user-defined datatypes. You must enter it as “timestamp” in all lowercase letters.