Type of facts
Type of facts | Explanation |
Additive | Measures should be added to all dimensio ... |
Semi-Additive | In this type of facts, measures may be a ... |
Non-Additive | It stores some basic unit of measurement ... |
Full Answer
What is the difference between facts and dimensions?
Key Differences Between Fact Table and Dimension Table
- Fact table contains measurement along the dimension/attributes of a dimension table.
- Fact table contains more records and less attribute as compared to dimension table whereas, dimension table contain more attributes and fewer records.
- The table size of fact table grows vertically whereas, table size of dimension table grows horizontally.
What is fact table and dimension table?
Key Differences Between Fact Table and Dimension Table
- Fact Table contains the values or measurements of the attributes of the dimension table.
- Fact table comprises of fewer attributes and more records whereas the dimension table comprises of lesser records and more attributes.
- The fact table grows vertically while the dimension table grows horizontally.
What are the different types of dimensions?
Types of Dimensions
- Slowly Changing Dimensions. It depends on the business requirement, where any particular feature history of changes in the data warehouse is preserved.
- Rapidly Changing Dimensions. ...
- Junk Dimensions. ...
- Stacked dimension. ...
- Deferred Dimension. ...
- Distorted Dimension. ...
- Degenerate Dimension. ...
- Role-playing Dimension. ...
- Shrunken Dimension. ...
- Fixed Dimension. ...
What are facts and dimensions in a data warehouse?
What is Dimensional Modeling in Data Warehouse?
- Elements of Dimensional Data Model. Facts are the measurements/metrics or facts from your business process. ...
- Steps of Dimensional Modelling. ...
- Rules for Dimensional Modelling. ...
- Benefits of Dimensional Modeling. ...
- Summary: A dimensional model is a data structure technique optimized for Data warehousing tools. ...
What are facts and dimensions with example?
Employees and customers are examples of dimensions, they do. Products are sold, they are also dimensions as they have something done to them. Facts, are the verb. An entry in a fact table marks a discrete event that happens to something from the dimension table.
What are the different types of facts?
We can divide the Facts in to these three types.Non-Additive.Semi-Additive.Additive.
What are the types of dimensions?
Top 9 Types of DimensionConformed Dimensions. A dimension is considered a conformed dimension and is found in many places. ... Role Playing Dimensions. ... Shrunken Dimensions. ... Static Dimensions. ... Degenerate Dimensions. ... Rapidly Changing Dimensions. ... Junk Dimensions. ... Inferred Dimensions.More items...
What are the 3 types of fact tables?
These are:Transaction fact tables.Periodic snapshot tables, and.Accumulating snapshot tables.
What is a fact and dimension?
Facts and dimensions are data warehousing terms. A fact is a quantitative piece of information - such as a sale or a download. Facts are stored in fact tables, and have a foreign key relationship with a number of dimension tables. Dimensions are companions to facts, and describe the objects in a fact table.
What is dimension and types of dimension?
Dimension: A dimension table has two types of columns, primary keys and descriptive data. For example, Time and Customer....Stacked dimension.Transaction_type_keyTransaction_typeCategory6Full deliveryPayment type7On deliveryPayment type6 more rows
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.
What are the types of dimensions and facts in data warehouse?
Types of Dimensions in Data Warehouse Conformed Dimension. Outrigger Dimension. Shrunken Dimension. Role-playing Dimension.
What are three basic types of dimensions?
There are three different types of dimensions on prints: Reference Dimensions, Tolerance Dimensions, and Basic Dimensions.
What are the types of dimension tables?
Types of Dimension TableSCD (Slowly Changing Dimensions) The dimension attributes that tend to change slowly with time rather than changing in a regular interval of time are called slowly changing dimensions. ... Conformed Dimension. ... Junk Dimension. ... Degenerate Dimension. ... Roleplay Dimension.
What is dimension table with example?
A dimension table or dimension entity is a table or entity in a star, snowflake, or starflake schema that stores details about the facts. For example, a Time dimension table stores the various aspects of time such as year, quarter, month, and day.
What are facts and dimensions in star schema?
Model. The star schema separates business process data into facts, which hold the measurable, quantitative data about a business, and dimensions which are descriptive attributes related to fact data. Examples of fact data include sales price, sale quantity, and time, distance, speed and weight measurements.
What is dimension in web design?
A website dimension consists of the website’s name and URL attributes. They describe different objects ...
What is dimension table?
Dimension tables often take the form of descriptive characteristics of facts and are helped by their attributes. Dimensions sometimes contain one or more hierarchical relationships.
What is junk dimension?
Junk dimensions form a collection of random transactional codes, text attributes, or flags. They often don’t logically belong to any specific dimension. Most often, the values of these attributes fall under simple (yes/no (or) true/false) indicators.
What is a shrunken rollup dimension?
Shrunken rollup dimensions are essentially subdivisions of columns and rows of a base dimension. These dimensions are great for developing aggregated fact tables. It’s handy when business processes naturally capture data at a higher level of granularity.
Why do we use degenerate dimensions?
As it’s derived from a fact table, it doesn’t have its own dimension. We use degenerate dimensions to collect snapshots of a fact table.
What is a fact table?
In a dimensional model, a fact table is a primary table. It contains facts, measurements, and metrics of a business process. It also acts as a foreign key to dimensional tables. The data stored in a fact table is often numerical. You can find a fact table at the center of a snowflake schema or star schema.
What is data warehousing facts?
In data warehousing, facts and dimensions are standard terms. They inform us about things like the number of resources used for a particular task. They both store the exact measure of resources and details about the resource and task.
How many columns are there in a fact table?
Technically, a Fact table has two types of columns, foreign keys to dimension tables and measures those that contain numeric Facts. Based on the business need and necessity there can be more attributes (technical/business related attributes) apart form the dimension keys and the numeric attributes. We can divide the Facts in to these three types.
What is a fact table?
Fact: A Fact table contains the Fact’s data, which are also termed as measures at a detailed level or aggregated (grouped, based on a key value) level. The fact attributes are usually numbers which can be used for calculating and grouping to address the business questions.
What is an additive fact?
Additive Facts: Additive Facts are Facts that can be summed up through all of the dimensions in the Fact table. For example, if there is a retail store and if we want to identify the total sales which have happened in the last six months, we can group the records of the last six months and get the summed up (aggregated) value.
What is a dimension that is used in multiple locations called?
A Dimension that is used in multiple locations is called a conformed dimension. A conformed dimension may be used with multiple fact tables in a single database, or across multiple data marts or data warehouses.
What is a dimension attribute that changes frequently?
A dimension attribute that changes frequently is a Rapidly Changing Attribute . If you don’t need to track the changes, the Rapidly Changing Attribute is no problem, but if you do need to track the changes, using a standard Slowly Changing Dimension technique can result in a huge inflation of the size of the dimension. One solution is to move the attribute to its own dimension, with a separate foreign key in the fact table. This new dimension is called a Rapidly Changing Dimension.
What is a role playing dimension?
A role-playing dimension is one where the same dimension key — along with its associated attributes — can be joined to more than one foreign key in the fact table. For example, a fact table may include foreign keys for both Ship Date and Delivery Date. But the same date dimension attributes apply to each foreign key, so you can join the same dimension table to both foreign keys. Here the date dimension is taking multiple roles to map ship date as well as delivery date, and hence the name of Role Playing dimension.
What is a degenerate dimension?
A degenerate dimension is when the dimension attribute is stored as part of fact table, and not in a separate dimension table . These are essentially dimension keys for which there are no other attributes. In a data warehouse, these are often used as the result of a drill through query to analyze the source of an aggregated number in a report. You can use these values to trace back to transactions in the OLTP system.
What is junk dimension?
A junk dimension is a single table with a combination of different and unrelated attributes to avoid having a large number of foreign keys in the fact table. Junk dimensions are often created to manage the foreign keys created by Rapidly Changing Dimensions.
Is a dimension record inferred?
While loading fact records, a dimension record may not yet be ready. One solution is to generate an surrogate key with Null for all the other attributes. This should technically be called an inferred member, but is often called an inferred dimension.
What is dimension table?
Dimension table: A dimension table contains dimensions of a fact. They are joined to fact table via a foreign key. Dimension tables are de-normalized tables. The Dimension Attributes are the various columns in a dimension table. Dimensions offers descriptive characteristics of the facts with the help of their attributes.
What is a degenerate dimension?
Degenerate dimension is without corresponding dimension. It is used in the transaction and collecting snapshot fact tables. This kind of dimension does not have its dimension as it is derived from the fact table. They are used when the same fact table is paired with different versions of the same dimension.
Where is the fact table located?
Fact table is located at the center of a star or snowflake schema, whereas the Dimension table is located at the edges of the star or snowflake schema. Fact table is defined by their grain or its most atomic level whereas Dimension table should be wordy, descriptive, complete, and quality assured.
When to use swappable dimensions?
Swappable Dimensions. They are used when the same fact table is paired with different versions of the same dimension. Step Dimensions. Sequential processes, like web page events, mostly have a separate row in a fact table for every step in a process.
Can dimensions be referenced to other dimensions?
Dimensions may have references to other dimensions. However, these relationships can be modeled with outrigger dimensions. Role-Playing Dimensions. A single physical dimension helps to reference multiple times in a fact table as each reference linking to a logically distinct role for the dimension. Junk Dimensions.
What is a fact table?
A fact table is the one which consists of the measurements, metrics or facts of business process. These measurable facts are used to know the business value and to forecast the future business. The different types of facts are explained in detail below. Additive facts are facts that can be summed up through all of the dimensions in the fact table.
What is a factless fact table?
Factless Fact Table: In the real world, it is possible to have a fact table that contains no measures or facts. These tables are called "Factless Fact tables". Eg: A fact table which has only product key and date key is a factless fact. There are no measures in this table.
What is an additive fact?
Additive facts are facts that can be summed up through all of the dimensions in the fact table. A sales fact is a good example for additive fact. Semi-additive facts are facts that can be summed up for some of the dimensions in the fact table, but not the others.