dgen_fld ::= 


  { RECNUM 
  | SYSDATE 
  | CONSTANT val 
  | SEQUENCE [( { COUNT | MAX | integer } [, incr] )] 
  | { REF_spec init_spec | SID_spec init_spec | BFILE_spec init_spec }
  | EXPRESSION \" sql string \" }

For information on how to read this syntax, see Appendix C.