Types of Fact Tables
There are basically three fundamental measurement events, which characterizes all fact tables.
- Transactional
- A transactional table is the most basic and fundamental. The grain associated with a transactional fact table is usually specified as "one row per line in a transaction", e.g., every line on a receipt. Typically a transactional fact table holds data of the most detailed level, causing it to have a great number of dimensions associated with it.
- Periodic snapshots
- The periodic snapshot, as the name implies, takes a "picture of the moment", where the moment could be any defined period of time, e.g. a performance summary of a salesman over the previous month. A periodic snapshot table is dependent on the transactional table, as it needs the detailed data held in the transactional fact table in order to deliver the chosen performance output.
- Accumulating snapshots
- This type of fact table is used to show the activity of a process that has a well-defined beginning and end, e.g., the processing of an order. An order moves through specific steps until it is fully processed. As steps towards fulfilling the order are completed, the associated row in the fact table is updated. An accumulating snapshot table often has multiple date columns, each representing a milestone in the process. Therefore, it's important to have an entry in the associated date dimension that represents an unknown date, as many of the milestone dates are unknown at the time of the creation of the row.
Read more about this topic: Fact Table
Famous quotes containing the words types of, types, fact and/or tables:
“The wider the range of possibilities we offer children, the more intense will be their motivations and the richer their experiences. We must widen the range of topics and goals, the types of situations we offer and their degree of structure, the kinds and combinations of resources and materials, and the possible interactions with things, peers, and adults.”
—Loris Malaguzzi (1920–1994)
“The rank and file have let their servants become their masters and dictators.... Provision should be made in all union constitutions for the recall of leaders. Big salaries should not be paid. Career hunters should be driven out, as well as leaders who use labor for political ends. These types are menaces to the advancement of labor.”
—Mother Jones (1830–1930)
“Your child should feel entitled to cry when you leave; crying is a natural thing for a child to do when she feels bad. The fact that your child cries when you go doesn’t mean she will never like day care. It just means she wants you to stay.”
—Amy Laura Dombro (20th century)
“Moving between the legs of tables and of chairs,
Rising or falling, grasping at kisses and toys,
Advancing boldly, sudden to take alarm,
Retreating to the corner of arm and knee,
Eager to be reassured, taking pleasure
In the fragrant brilliance of the Christmas tree....”
—T.S. (Thomas Stearns)