i use discoverer desktop 9i.
i would like to know if there is any limitation for the number of values entered in a parameter (if the values are numbers)
or if there is a length limitation for the parameter value (if the vale is string)
If you are asking about the maximum size of an "in list" for number, the size is 1000.
If you are asking how many digits can a prompt have (associated with datatype NUMBER), it is 38 which corresponds with the number of significant digits associated with a NUMBER datatype.
For varchar2 parameters, I would stick with varchar2 less than 4000 bytes.