types of fact tables in informatica

Types of Fact Tables

• Fact-less Fact Tables. A fact table that does not contain any measure is a fact-less fact table. This table will only...
• Centipede Fact Table. Centipede fact table is a normalized fact table. Modeller may decide to normalize the fact instead...
• Conformed Fact Tables. They are measures re-used across multiple dimension models.

Full Answer

What are the different types of Fact tables?

The different types of fact tables are as explained below: There are three types of facts: Additive facts can be used with any aggregation function like Sum (), Avg () etc. Example is Quantity, sales amount etc. Semi-additive facts are those where only a few of aggregation function can be applied. For example, Consider bank account details.

What are fact tables in data warehouse?

They are measures re-used across multiple dimension models. A fact table stores some kind of measurements and are captured against a specific time. Now it might so happen that the business might not able to capture all of its measures always for every point in time.

What is a fact table in SQL Server?

Facts are also known as measurements or metrics. A fact table record captures a measurement or a metric. In the schema below, we have a fact table FACT_SALES that has a grain that gives us the number of units sold by date, by store, and product. All other tables such as DIM_DATE, DIM_STORE and DIM_PRODUCT are dimensions tables.

How to get the most useful data from a fact table?

To obtain the most useful data in a fact table or entity, you should use measures that are both numeric and additive. Using these measures guarantees that data can be retrieved and aggregated, so that the business can make use of the wealth of business data in the database. Fact tables and entities also contain foreign keys to the dimension tables.

What are the 3 types of fact tables?

These are:Transaction fact tables.Periodic snapshot tables, and.Accumulating snapshot tables.

What are the main types of facts?

The different types of facts are explained in detail below.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. ... Non-Additive:

What are the 2 kinds of data that a fact tables contain?

Thus, the fact table consists of two types of columns. The foreign keys column allows joins with dimension tables, and the measures columns contain the data that is being analyzed.

How many fact tables are there?

There are four types of fact tables: transaction, periodic snapshot, accumulating snapshot and factless fact tables.

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 are different types of facts controllers?

There are three major facets of FACTS controllers. They are shunt controllers, series controllers and phase angle controllers. These are combined categorized also as combined series-series and combined series-shunt controllers.

Is fact table normalized or denormalized?

A fact table is always DENORMALISED table. It consists of data from dimension table (Primary Key's) and Fact table has Foreign keys and measures.

What types of fields can a fact table have?

A fact table can store different types of measures such as additive, non-additive, semi-additive.

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. Additionally, any table in a dimensional database that has a composite key must be a fact table.

How many types of fact tables are there in data warehouse?

three typesThere are three types of fact tables and entities: Transaction. A transaction fact table or transaction fact entity records one row per transaction. Periodic.

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.

Can we have more than 1 fact table?

A data warehouse can have more than one fact table. However, you do want to minimize joins between fact tables. It's ok to duplicate fact information in different fact tables.

What is transaction fact table?

Transaction fact tables are easy to understand: a customer or business process does some thing; you want to capture the occurrence of that thing, and so you record a transaction in your data warehouse and you’re good to go.

Why do periodic snapshot tables have a large number of fields?

This is because any reasonably interesting metric may be shoved into the period table.

What is accumulating snapshot table?

Unlike periodic snapshot tables, accumulating snapshot tables are a little harder to explain. To understand why Kimball and his peers came up with this approach, it helps to understand a little about the kinds of questions that were being asked of business in the 90s, which was when the Data Warehouse Toolkit was first written.

What is a fact table?

A fact table stores quantitative information for analysis and is often denormalized. A fact table holds the measures, metrics and other quantifiable information. The different types of fact tables are as explained below:

What is a fact table that does not contain any measure?

A fact table that does not contain any measure is a fact-less fact table. This table will only contain keys from different dimension tables. This is often used to resolve a many-to-many cardinality issue.

Can you use aggregation functions on non-additive facts?

You cannot use numeric aggregation functions such as Sum (), Avg () etc on Non-additive facts. For example of non-additive fact is any kind of ratio or percentage. Non numeric facts can also be a non-additive facts.

How to create a fact table?

Here is an overview of four steps to designing a fact table described by Kimball: 1 Choosing business process to a model – The first step is to decide what business process to model by gathering and understanding business needs and available data 2 Declare the grain – by declaring a grain means describing exactly what a fact table record represents 3 Choose the dimensions – once the grain of the fact table is stated clearly, it is time to determine dimensions for the fact table. 4 Identify facts – identify carefully which facts will appear in the fact table.

What are the different types of measures in a fact table?

Measure types. Fact table can store different types of measures such as additive, non-additive, semi-additive. Additive – As its name implied, additive measures are measures which can be added to all dimensions.