What is a database fact table?
A fact table is the central table in a star schema of a data warehouse. A fact table stores quantitative information for analysis and is often denormalized. The foreign keys column allows joins with dimension tables, and the measures columns contain the data that is being analyzed.
What is fact table with example?
A fact table is found at the center of a star schema or snowflake schema surrounded by dimension tables. A fact table consists of facts of a particular business process e.g., sales revenue by month by product. Facts are also known as measurements or metrics. A fact table record captures a measurement or a metric.
How do you create a fact table?
Steps in designing Fact Table:
- Identify a business process for analysis(like sales).
- Identify measures or facts (sales dollar).
- Identify dimensions for facts(product dimension, location dimension, time dimension, organization dimension).
- List the columns that describe each dimension.
What is fact table and its types?
The fact table is a central table in the data schemas. It is found in the centre of a star schema or snowflake schema and surrounded by a dimension table. It contains the facts of a particular business process, such as sales revenue by month.
Why do we need fact table?
Fact tables provide the (usually) additive values that act as independent variables by which dimensional attributes are analyzed. Fact tables are often defined by their grain. The grain of a fact table represents the most atomic level by which the facts may be defined.
What are the different types of facts?
There are three types of facts:
- Additive: Additive facts are facts that can be summed up through all of the dimensions in the fact table.
- 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.
Can fact table have primary key?
The fact table also has a primary (composite) key that is a combination of these four foreign keys. As a rule, each foreign key of the fact table must have its counterpart in a dimension table. Therefore a dimension table can also be a fact table for a separate star schema.
What are the three types of facts?
What are different types of fact table?
There are three types of fact tables:
- Transaction Fact Table. The transaction fact table is a basic approach to operate the businesses.
- Snapshot Fact Table. The snapshot fact table describes the state of things at a particular time and contains many semi-additive and non-additive facts.
- Accumulated Fact Sheet.
What are three types of facts?
Can we join two fact tables?
Joining fact tables can be done but there are some inherent risks so you need to be careful when joining fact tables is required. In the following simple scenario, we have a fact of authors to articles and a separate fact of articles to pageviews.