Full Answer
What is a factless fact table in data warehousing?
Data Warehousing > Concepts > Factless Fact Table. A factless fact table is a fact table that does not have any measures. It is essentially an intersection of dimensions. On the surface, a factless fact table does not make sense, since a fact table is, after all, about facts.
What are the two types of factless tables?
There are two types of factless tables: One is for capturing an event, and one is for describing conditions. An event establishes the relationship among the dimension members from various dimensions, but there is no measured value. The existence of the relationship itself is the fact.
What is an event-based factless fact table?
An event-based factless fact table is student attendance information; the grain of the fact table is one row per student each day.
What is a fact less fact table in ATS?
A tracking process or collecting status can be performed by using fact less fact tables. The fact table does not have numeric values that are aggregate, hence the name. Mere key values that are referenced by the dimensions, from which the status is collected, are available in fact less fact tables.
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 factless fact in data warehouse?
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.
How many attributes does factless fact table have?
There are two kinds of factless fact tables: Factless fact table describes events or activities. Factless fact table describes a condition, eligibility, or coverage.
What are the three types of fact tables?
There are three types of fact tables and entities: Transaction. A transaction fact table or transaction fact entity records one row per transaction. Periodic.
What is the meaning of Factless?
Lacking facts; inaccurate or fictionalfactless (comparative more factless, superlative most factless) Lacking facts; inaccurate or fictional.
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 factless fact in Microstrategy?
A factless fact table is table that doesn't have fact at all. They may consist of nothing but keys. There are tow types of factless fact table. 1-> event 2-> coverage.
Is star schema normalized or denormalized?
Star schema's dimension tables do not contain any foreign keys. That is, the dimension tables do not reference any other tables, nor do they have any "sub-dimension tables." They are generally denormalized because some information may be duplicated in the dimension tables.
What are the SCD types?
What are the types of SCD?Type 0 – Fixed Dimension. No changes allowed, dimension never changes.Type 1 – No History. Update record directly, there is no record of historical values, only current state.Type 2 – Row Versioning. ... Type 3 – Previous Value column. ... Type 4 – History Table. ... Type 6 – Hybrid SCD.
Can we join 2 fact tables?
The answer for both is "Yes, you can", but then also "No, you shouldn't". Joining fact tables is a big no-no for four main reasons: 1. Fact tables tend to have several keys (FK), and each join scenario will require the use of different keys.
How many fact tables are there?
There are four types of fact tables: transaction, periodic snapshot, accumulating snapshot and factless fact tables.
Which are two types of fact?
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.More items...
Factless fact table for event or activity
When designing a dimensional model, you often find that you want to track events or activities that occur in your business process but you can’t find measures to track. In these situations, you can create a transaction-grained fact table that has no facts to describe that events or activities.
Factless fact table for event or activity example
For example, you may want to track employee leaves. How often and why your employee leaves are very important for you to plan your daily activities and resources.
What is a factless table?
Factless Fact Table. A factless fact table is a fact table that does not have any measures. It is essentially an intersection of dimensions. On the surface, a factless fact table does not make sense, since a fact table is, after all, about facts.
Why is adding a fact that always shows 1 redundant?
However, adding a fact that always shows 1 is redundant because we can simply use the COUNT function in SQL to answer the same questions.
About Factless Fact Table
This tutorial assumes that the reader is familiar with SQL Server database and data warehouse business intelligence concepts. As well as is comfortable with the common terms used and applied in this field (of business intelligence).
When to use Factless FACT Tables
In order to understand the use of Factless FACT table we have to refer to, Kimball Group, one of the earliest pioneers in the field of Data Warehouse. According to Kimball Group, "It is possible that the event merely records a set of dimensional entities coming together at a moment in time.
How to use FactLess FACT Table
Let us now look at a common example of how to use a Factless Fact table.
What is a factless table?
Factless fact table. A factless fact table is a fact table that does not have any measures. It is essentially an intersection of dimensions (it contains nothing but dimensional keys). There are two types of factless tables: One is for capturing an event, and one is for describing conditions.
What are the two types of factless tables?
There are two types of factless tables: One is for capturing an event, and one is for describing conditions. An event establishes the relationship among the dimension members from various dimensions, but there is no measured value. The existence of the relationship itself is the fact.