In data warehousing, a lot of information is gathered together in one place to make it easier to understand and use. One popular way to organize all the data is through "star schema design".
All the important information is in one main table in this design, such as how much was sold and when. Besides this table, there are other tables with additional details about the orders, customers, and products. You can easily find the information you're looking for this way.
Star schema design uses something called "Slowly Changing Dimensions" or SCDs are used in star schema design to keep track of changes over time. Type 1 and Type 2 SCDs are the two types.
Type 1 SCDs are like erasers. During the process, old information is erased and replaced with new information. If you only need the most recent information, this is useful. When a product's price changes, the old price disappears and is replaced by the new one.
A Type 2 SCD is like a time machine since it creates new rows as changes occur over time. In this way, you can track the changes over time. A customer's address would be updated if he or she moved.
To use SCDs, we could set up a table for products, and then use Type 1 SCDs to change prices. The old prices would be erased and replaced with new ones. To show how a customer's address has changed over time, we could create a table for customers and use Type 2 SCDs for address changes.
It is important for businesses to have star schemas and SCDs. They can help businesses organize and understand a lot of information, which can aid in making better decisions. The table mentioned in the text is called a "Fact Table" and contains information about orders made by customers for particular products. Here's what a table might look like:
Order IDProduct IDCustomer IDOrder DateQuantity11001012022-01-01221011022022-01-02131001032022-01-033
Here is an example of a table with five columns:
An order ID is a unique identifier for each order.
Each product has a unique identifier.
The customer ID is a unique identifier for each customer.
Date of Order: The date on which the order was placed.
Quantity of goods ordered in the order.
The Order ID, Product ID, and Customer ID columns are called "foreign keys" and link to dimension tables containing additional information about the orders, products, and customers.
The table mentioned in the text is called a "Fact Table" and contains information about orders made by customers for specific products.
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