Contents
What is the difference between fact tables and dimension tables?
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 on the attributes of a dimension table. While in dimension table, There is more attributes than fact table.
What is a dimension lookup table?
Every dimension table has a column that contains the primary key, which uniquely identifies each row n the dimension. The dimension table is linked to the fact table using the primary key. Look Up Table: Also known as LUT in short, Look Up table is actually an array that is used in computer programming.
What is a dimension in star schema?
Dimension tables store supporting information to the fact table. Each star schema database has at least one dimension table, but will often have many. Each dimension table will relate to a column in the fact table with a dimension value, and will store additional information about that value.
What is the use of lookup table?
A lookup table or lookup file holds static data and is used to look up a secondary value based on a primary value.
What is the other term used for reference table?
A reference table (or table of reference) may mean a set of references that an author may have cited or gained inspiration from whilst writing an article, similar to a bibliography. It is also called a domain table because it represents the domain for the columns that reference it.
What are the dimensions of a star schema?
Time dimension table contains the attributes: Order ID, Order Date, Year, Quarter, Month. In Star Schema, Business process data, that holds the quantitative data about a business is distributed in fact tables, and dimensions which are descriptive characteristics related to fact data.
What is the relationship between a fact table and a star schema?
In a star schema, only single join defines the relationship between the fact table and any dimension tables. Star schema contains a fact table surrounded by dimension tables.
What’s the difference between snowflake schema and star schema?
Let’s see the difference between Star and Snowflake Schema: 1. In star schema, The fact tables and the dimension tables are contained. While in snowflake schema, The fact tables, dimension tables as well as sub dimension tables are contained. 2. Star schema is a top-down model. While it is a bottom-up model.
How are external fields represented in star schema?
For star schema, every external field in the fact table is represented by just one reference table. For example, consider the following fact table: In this table, Department_id, Product_id, and Customer_id are the fields that contain references to an external table. Amount is just a numeric field.