sp_dbextend uses this syntax:
sp_dbextend [ command [, arguments...] ]
where command is one of the options discussed below, and arguments specifies the database name, segment name, amount of free space, and so on. See the Reference Manual: Procedures.
If you do not include an argument, sp_dbextend defaults to help. See the Reference Manual: Procedures.
The automatic expansion procedure does not create new
devices; it only alters the size of the database and segment on
existing devices to which the segment currently maps.
To discontinue threshold action procedure, clear the threshold using the sp_dropthreshold, or use sp_dbextend with the clear option. See the Reference Manual: Procedures.