Global_star.gif is a diagram of a star schema. In the center is the UNITS_HISTORY_FACT table, with a composite primary key, made of four foreign keys: MONTH_ID, ITEM_ID, SHIP_TO_ID, and CHANNEL_ID. The table has one other column, UNITS, which is a fact column for number of units. Joined to this table are four other tables: TIME_DIM, which has MONTH_ID as its primary key and several other attributes such as MONTH_DESC, QUARTER_ID, QUARTER_DESC, YEAR_ID, and so on; PRODUCT_DIM, which has ITEM_ID as its primary key and other attributes such as ITM_DSC, ITEM_PACKAGE_ID, FAMILY_ID, FAMILY_DSC, and so on; CHANNEL_DIM, which has CHANNEL_ID as its primary key and CHANNEL_DSC, ALL_CHANNELS_ID, and ALL_CHANNELS_DSC as its other attributes; and CUSTOMER_DIM, which has SHIP_TO_ID as its primary key, with other attributes such as SHIP_TO_DSC, ACCOUNT_ID, ACCOUNT_DSC, and so on.