What is factless fact table with example?
A factless fact table is a fact table that does not have any measures, i.e. any numeric fields that can be aggregated. For example, if you are modelling product sales, you can have a Sales fact table that will contain the dimension keys and, for example, the “amount” value/measure, to record the amount sold.
What is a factless fact table in ETL?
Factless tables simply mean the key available in the fact that no remedies are available. Factless fact tables are only used to establish relationships between elements of different dimensions. And are also useful for describing events and coverage, meaning tables contain information that nothing has happened.
What is fact table in Informatica?
A fact table is a primary table in a dimensional model. A Fact Table contains. Measurements/facts. Foreign key to dimension table.
What is the meaning of Factless?
Lacking facts; inaccurate or fictional
factless (comparative more factless, superlative most factless) Lacking facts; inaccurate or fictional.
What is the use of junk dimension?
A junk dimension is a convenient grouping of typically low-cardinality flags and indicators. By creating an abstract dimension, these flags and indicators are removed from the fact table while placing them into a useful dimensional framework.
What is junk dimension with example?
A Junk Dimension is a dimension table consisting of attributes that do not belong in the fact table or in any of the existing dimension tables. The nature of these attributes is usually text or various flags, e.g. non-generic comments or just simple yes/no or true/false indicators.
What is difference between fact table and dimension table?
The main difference between fact table or reality table and the Dimension table is that dimension table contains attributes on that measures are taken actually table. 1. Fact table contains the measuring of the attributes of a dimension table.
What are the 2 kinds of data that a fact tables contain?
Thus, a fact table consists of two types of columns. The foreign keys column allows to join with dimension tables and the measure columns contain the data that is being analyzed. A Transaction table is the most basic and fundamental view of business operations.
How many fact tables are there?
There are four types of fact tables: transaction, periodic snapshot, accumulating snapshot and factless fact tables.
What is a junk table?
What is junk dimension in Informatica?
Why do we use junk dimension?
A junk dimension combines several low-cardinality flags and attributes into a single dimension table rather than modeling them as separate dimensions. There are good reasons to create this combined dimension, including reducing the size of the fact table and making the dimensional model easier to work with.
What is the use of fact table?
A fact table stores quantitative information for analysis and is often denormalized. A fact table works with dimension tables. A fact table holds the data to be analyzed, and a dimension table stores data about the ways in which the data in the fact table can be analyzed.
Why is a fact table used?
Which schema has multiple fact tables?
A star schema is a data model that stores information in multiple table types: a single fact table and multiple dimensional tables.
What is a factless fact table?
By definition, the factless fact table is a fact table that does not contain any facts. There are two kinds of factless fact tables: Factless fact table describes events or activities. Factless fact table describes a condition, eligibility, or coverage. Both kinds of factless fact tables play a very important role in your dimensional model design.
What are the two parts of a factless query?
These queries always have two parts: a factless coverage table that contains all the possibilities of events that might happen and an activity table that contains the events that did happen. When the activity is subtracted from the coverage, the result is the set of events that did not happen.
What is fact table in data warehouse?
A Fact table is typically a table created in a data warehouse which contains facts such as total number of employees in an organization or average sales figures for all the products and so on. How a dimension is related to a fact table?
What is the fact_leave table?
At the center of the diagram below is the FACT_LEAVE table that has no facts at all. However, the FACT_LEAVE table is used to measure employee leave the event when it occurs. The following SQL statement is used to count the number of leaves that an employee has been taken: