Basics - What are Semi-additive and factless facts and in which scenario will you use such kinds of fact tabl

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What are Semi-additive and factless facts and in which scenario will you use such kinds of fact tables

Total Answers and Comments: 4

Last Update: August 03, 2007

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Submitted by: Santanu Patra

Semi-Additive: Semi-additive facts are facts that can be summed up for some of the dimensions in the fact table, but not the others. For example:
Current_Balance and Profit_Margin are the facts. Current_Balance is a semi-additive fact, as it makes sense to add them up for all accounts (what's the total current balance for all accounts in the bank?), but it does not make sense to add them up through time (adding up all current balances for a given account for each day of the month does not give us any useful information

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phdsong, cfo_2016

June 29, 2005 06:43:47

Santanu Patra

RE: What are Semi-additive and factless facts and in which scenario will you use such kinds of fact tabl...

Semi-Additive: Semi-additive facts are facts that can be summed up for some of the dimensions in the fact table but not the others. For example:
Current_Balance and Profit_Margin are the facts. Current_Balance is a semi-additive fact as it makes sense to add them up for all accounts (what's the total current balance for all accounts in the bank?) but it does not make sense to add them up through time (adding up all current balances for a given account for each day of the month does not give us any useful information

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June 29, 2005 06:45:54

Santanu Patra

RE: What are Semi-additive and factless facts and in which scenario will you use such kinds of fact tabl...

A factless fact table captures the many-to-many relationships between
dimensions but contains no numeric or textual facts. They are often used to record events or
coverage information. Common examples of factless fact tables include:
- Identifying product promotion events (to determine promoted products that didn t sell)
- Tracking student attendance or registration events
- Tracking insurance-related accident events
- Identifying building facility and equipment schedules for a hospital or university

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July 25, 2007 12:53:00

SANTOSH SHINDE

RE: What are Semi-additive and factless facts and in w...

There has been so much talk about numeric additive values in fact tables that it may come as a surprise that two kinds of very useful fact tables don't have any facts at all! They may consist of nothing but keys. These are called factless fact tables.

first type of factless fact table is a table that records an event. Many event-tracking tables in dimensional data warehouses turn out to be factless.

A second kind of factless fact table is called a coverage table. Coverage tables are frequently needed when a primary fact table in a dimensional data warehouse is sparse.

Good Luck

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August 03, 2007 08:05:20

siraj.khan

RE: What are Semi-additive and factless facts and in w...

Semi-additive facts are those facts which can be aggregate according to the context. so it can contain a fact but the factless fact table does not contain fact's but it contains the dimmentions. It's a type of a dimmentions.

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