# What Are Fact And Dimension Tables

Fact tables and dimension tables are two of the most important tables in a relational database. The fact table contains the actual data, while the dimension table contains the information about the data.

The fact table is usually the largest table in the database, and it contains the data that is being processed or analyzed. The dimension table contains the information about the data in the fact table, such as the date, time, and location.

The fact table and the dimension table are linked together by the primary key and the foreign key. The primary key is the column in the fact table that is used to link to the dimension table, and the foreign key is the column in the dimension table that is used to link to the fact table.

The fact table and the dimension table are usually created at the same time, and they are usually created together in the same database. The fact table and the dimension table are also usually updated at the same time.

The fact table and the dimension table are important because they contain the data that is being processed or analyzed. The fact table contains the actual data, while the dimension table contains the information about the data.

## What is a fact and dimension?

What is a fact and dimension?

A fact is a statement that is known to be true, while a dimension is a measure of some property. In mathematics, a dimension is a measure of the size of a geometric object or a space. For example, a line has one dimension, a plane has two dimensions, and a three-dimensional space has three dimensions.

The dimension of a mathematical object is always a positive integer. The dimension of a space is the maximum number of linearly independent directions in which a point can move. In other words, it is the maximum number of coordinates needed to specify a point in the space.

The dimension of a vector space is the maximum number of linearly independent vectors that can be formed from the vectors in the space. The dimension of a matrix space is the maximum number of linearly independent matrices that can be formed from the matrices in the space.

The dimension of a Euclidean space is the number of coordinates needed to specify a point in the space. The dimension of a non-Euclidean space is not necessarily the same as the dimension of a Euclidean space.

The dimension of a topological space is the minimum number of dimensions needed to specify a point in the space. A point in a topological space can be specified using a coordinate tuple, a point cloud, or a point set.

## How do you identify fact and dimension in a table?

In order to identify the fact and dimension in a table, you need to understand the meaning of each column and row header. The column headers represent the dimension, while the row headers represent the measure or fact. In order to identify the fact and dimension in a table, you need to understand the meaning of each column and row header. The column headers represent the dimension, while the row headers represent the measure or fact.

## What is the difference between a fact able and a dimension table?

In the world of big data, there are two types of tables: fact tables and dimension tables. Understanding the difference between these two types of tables is crucial to mastering big data.

Fact tables are tables that contain facts. Facts are pieces of information that can be used to answer questions about what has happened or is happening. For example, a fact table might contain information about how many products a company has sold in a given month.

Dimension tables, on the other hand, are tables that contain dimensions. Dimensions are pieces of information that can be used to answer questions about how something happened or is happening. For example, a dimension table might contain information about the different types of products that a company sells.

The difference between fact tables and dimension tables is important because it affects how you query your data. When you query a fact table, you are asking questions about what has happened or is happening. When you query a dimension table, you are asking questions about how something happened or is happening.

For example, consider the fact table below:

fact_table

product_id

quantity

unit_price

This table contains information about the products that a company has sold. You can use this table to answer questions like “How many products were sold?” and “What was the average price per product?”

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Now consider the dimension table below:

dim_table

product_type

category

brand

This table contains information about the different types of products that a company sells. You can use this table to answer questions like “What types of products does the company sell?” and “What categories does the company sell products in?”

The difference between fact tables and dimension tables is important because it affects how you structure your data. When you have a fact table and a dimension table, you can join them together to create a star schema. A star schema is a type of data structure that is optimized for querying data.

When you join a fact table and a dimension table, the fact table becomes the star of the schema. The dimension table becomes the surrounding structure. This structure is called a star schema because it looks like a star when you diagram it.

The star schema is important because it is optimized for querying data. When you query a fact table, the data is automatically filtered through the dimensions in the dimension table. This means that you can get answers to questions about how something happened or is happening without having to join multiple tables.

The star schema is the most common data structure for big data. If you want to master big data, you need to be able to create star schemas and understand how to query data.

## What is fact table with example?

A fact table is a data table in a data warehouse or business intelligence system that stores facts. A fact table typically has a foreign key to a dimension table, and stores a numeric value for each row.

A fact table is a critical component of a data warehouse or business intelligence system. It is a key part of the data model, and is used to support decision-making. Fact tables are often described as the “meat and potatoes” of data warehousing, because they contain the data that is used to answer business questions.

Fact tables are usually quite large, and can be hundreds of gigabytes in size. They are usually normalized, and contain only the facts that are necessary to answer specific business questions.

Fact tables are often joined with dimension tables to create a star schema. A star schema is a data model that is used to support decision-making. It is named for the star-shaped diagram that is used to depict it. The star schema is the most common data model used in data warehousing.

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The following is an example of a fact table:

Dimension Table:

Customer

Product

Date

Transaction

Fact Table:

Customer

Product

Date

Transaction

Quantity

Unit Price

## What is dimension table with example?

A dimension table is a table that is used as a reference to help understand the data in another table. It is usually used in conjunction with a fact table. The dimension table contains descriptive information about the data in the fact table.

For example, imagine a company that sells products online. The fact table would contain information about the sales of these products, such as the date of the sale, the product name, the quantity sold, and the price. The dimension table would contain information about the products, such as the product name, the description, the price, and the color. This would help to understand the data in the fact table better.

dimension tableĀ

fact table

## What is fact table in SQL?

A fact table is a table in a data warehouse that stores measures, which are quantitative values that are of interest to business users. The measures are typically derived from the data in the operational system. The dimensions in a fact table are typically used to group and aggregate the measures.

## What are different types of fact tables?

Fact tables are one of the most important constructs in data warehousing and business intelligence. A fact table is simply a table that contains facts, as opposed to dimensions.

There are different types of fact tables, and each type has its own benefits and drawbacks. The most common types of fact tables are:

1. Transaction fact tables

2. Periodic snapshot fact tables

3. Slowly changing dimension (SCD) fact tables

Transaction fact tables are the most common type of fact table. They contain facts for individual transactions. This type of fact table is ideal for data warehouses that are used for online transaction processing (OLTP).

Periodic snapshot fact tables are similar to transaction fact tables, but they contain facts for a fixed time period, rather than for individual transactions. This type of fact table is ideal for data warehouses that are used for online analytical processing (OLAP).

Slowly changing dimension (SCD) fact tables are used to track changes to data over time. This type of fact table is ideal for data warehouses that are used for data mining and business intelligence.