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Facts and Fact table- Data warehouse fundamentals- part 5

Types of fact table
Fact tables are of two types
  1. CFT (Cumulative fact table)
  2. SFT (Snap Shot fact table)


Cumulative fact table
If we are loading the values into fact table based on time, then that is called cumulative fact table.

Snap Shot fact table
If we are loading the values based on client requirement, then that is called snap shot fact tables.

Types of facts

Fact: Fact is a numeric value, based on that numeric value; we are going to analyze data.
There are three types of facts are there. They are as follows.
  1. Additive fact
  2. Semi additive fact
  3. Non additive fact


Additive fact: - If fact values are coming from all dimensional tables, then such a fact is called additive fact.

Semi additive fact: - If fact values are coming from few dimension tables, then that is called semi additive fact.
Example: Transactions at bank (say if I drop deposit some money in my mom’s account, she only gets to know that amount is credited. She won’t know who credited money or how it is credited etc.)
Non additive fact: - If facts are not coming from any dimension table, then it is called Non additive fact.


REVENUE
PROFIT
PROFIT PERCENTAGE
20000
2000
-----------
40000
4000
50%

Here Revenue and profit are facts and profit percentage which is also a fact, is calculated using these two facts.
Here we can observe that Profit percentage values are not coming from any dimension tables.
Some more examples are Profits, Loss, gains, Ratio etc.


Factless Fact: - If fact table cannot contain any facts, then it is called factless fact.

SLNO
PID
LID
TID
CID
REVENUE
PROFIT
1
22
356
459
16
25,000
6000
2
56
45
546
75
60,000
4500
Upto






71
-----
----------
400 (Representing June 4th)
---------
----------
--------
72
52
56
985
21
75,321
9000


Here we know that by table that there is no sale happened on June 4th (TID- 400). So analysis is done why ‘No sale’ happened on that day.

Factless fact is basically used for negative analysis.

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