Transaction fact tables are the most fundamental view of the business’s operations. This type of table represents an event that occurred at an instantaneous point in time. A row is added to the table for each event occurrence. For example, when an order is entered into the ERP system (or “booked”), there will be an Order Booking transaction for each order line.

Periodic Snapshots are required to see the cumulative performance of the business at regular, predictable time intervals, weekly or monthly for example. A picture (i.e. “Snapshot”) is taken at the specified interval. For example, we may want to know our Open Order amounts at the end of each month.

History Fact Tables, or Accumulating tables, cover the complete life of a transaction. They represent an indeterminate time span. These types of tables always have multiple date and time stamps. An example of an accumulating table is a Sales Order history table that has a row for each change in the “life” of an order line. An order is placed (booked), shipped, invoiced, etc.