If the measures columns in the source data contain summary data, the time-related column must indicate the time period for which the data is summarized. For example, assume that the SALESINVACT table contains measures columns SALES and COGS; a date-related column, TRANSDATE; and STATE and PRODCODE columns that categorize by sales date, state, and product code.
Each row in the SALESINVACT table summarizes product sales and costs for a particular date for customers from a particular state. A row can also summarize data by other periods; for example, by week.