If your database consist all dates something like 01/02/2000 or 01-Feb-2000, you will need to break the date field into year, qtr,month & if required date.

to do this, create a class named TIME, under that create new object, in it's select box use oracle's date functions to get required information.

For E.g. : to_char(sales_date, 'YYYY') for getting only year from the date.

similarly, for quarter you can use to_char(sales_date, 'Q')

& for month to_char(sales_date, 'MM') for month number, instead of 'MM' if you use 'MON' it will return you abrevations like Jan for January & so on. for full name of month use 'MONTH'