What is a DataWarehouse and how can you benefit from it?

1. What the h**l is a Data Warehouse?

A Data Warehouse (DWH) is a large, centralized repository of data that is used to support business intelligence activities, such as reporting, data analysis, and decision making. Think of it like a giant library of data, where all the information is organized and easily accessible for anyone who needs it.

Data warehouses are important because they provide a single source of truth for an organization’s data, allowing for more accurate and consistent reporting and analysis. They also make it easier to access and analyze large amounts of data, which can help organizations make better, data-driven decisions.

In this article, we’ll explain what a data warehouse is, how it differs from a database, and why it’s important. We’ll also discuss the main components of a data warehouse, the benefits of using one, and how it works. Whether you’re a coder, engineer, data professional, or just someone who wants to learn more about data warehousing, this article is for you. So let’s get started!

2. Differences between DataLake and DataWarehouse

A Data Lake is like a big pool of raw data, where all the data is stored in its original format, without any structure or organization. Think of it like a giant box of assorted Lego bricks, where you can find all kinds of different pieces, but you have to dig through them to find what you need.

On the other hand, a DataWarehouse is like a neatly organized Lego set, where all the pieces are sorted and labeled, making it easier to find and use the ones you need. In a DataWarehouse, the data is structured, organized, and cleaned, making it easier to access and analyze .A data warehouse can be compared to a library, where books are collected from different sources, organized by categories and topics, stored on shelves, and accessed by users who want to read or learn from them.

The main difference between a DataLake and a DataWarehouse is the level of organization and structure. A DataLake is good for storing large amounts of raw data, while a DataWarehouse is better for storing structured data that is ready for analysis.

The pros of using a DataLake are that it can store any type of data, it’s scalable, and it’s relatively inexpensive. The cons are that it requires more effort to access and analyze the data, and it can be difficult to ensure data quality and consistency.

The pros of using a DataWarehouse are that it provides fast and easy access to structured data, it ensures data quality and consistency, and it supports business intelligence activities. The cons are that it can be more expensive, it requires more effort to set up and maintain, and it may not be suitable for storing unstructured data.

In conclusion, whether you choose to use a DataLake or a DataWarehouse depends on your needs. If you need to store large amounts of raw data and you don’t mind putting in the effort to access and analyze it, a DataLake might be a good choice. If you need fast and easy access to structured data for reporting and analysis, a DataWarehouse might be a better choice.

3. The most well-known DataWarehouses in the market 

There are several well-known data warehouses that are widely used by organizations for their business intelligence activities. Some of the most popular data warehouses include:

• Amazon Redshift: This is a cloud-based data warehouse that is part of the Amazon Web Services (AWS) platform. Redshift is designed for large-scale data warehousing and analytics, and it offers fast query performance, scalability, and security. Redshift was launched in 2012, and it is based in the US. The URL of Redshift is https://aws.amazon.com/redshift/.
• Google BigQuery: This is a cloud-based data warehouse that is part of the Google Cloud Platform (GCP). BigQuery is designed for big data analytics, and it offers fast query performance, scalability, and support for machine learning. BigQuery was launched in 2010, and it is based in the US. The URL of BigQuery is https://cloud.google.com/bigquery/.
• Microsoft Azure SQL Data Warehouse: This is a cloud-based data warehouse that is part of the Microsoft Azure platform. Azure SQL Data Warehouse is designed for large-scale data warehousingand analytics, and it offers fast query performance, scalability, and integration with other Azure services. Azure SQL Data Warehouse was launched in 2015, and it is based in the US. The URL of Azure SQL Data Warehouse is https://azure.microsoft.com/en-us/services/synapse-analytics/.
• Snowflake: This is a cloud-based data warehouse that is designed for big data analytics. Snowflake offers fast query performance, scalability, and support for a wide range of data formats, including structured and semi-structured data. Snowflake was launched in 2014, and it is based in the US. The URL of Snowflake is https://www.snowflake.com/.
• Teradata: This is a data warehouse that is designed for large-scale data warehousing and analytics. Teradata offers fast query performance, scalability, and support for a wide range of data formats, including structured and semi-structured data. Teradata was founded in 1979, and it is based in the US. The URL of Teradata is https://www.teradata.com/ 

These data warehouses are popular because they offer fast query performance, scalability, and support for a wide range of data formats. They also offer integration with other cloud services and support for machine learning, which makes them ideal for big data analytics and business intelligence activities.

Choosing the right data warehouse for your organization depends on your specific data needs and requirements. Some factors to consider include the size and complexity of your data, the types of data you need to store and analyze, and the level of performance and scalability you need. It’s also important to consider the cost of the data warehouse, as well as the level of support and integration with other cloud services.

4. Why should you use a Data Warehouse? 

There are several benefits of using a data warehouse, including:

• Improved Data Quality: Data warehouses are designed to store and manage large amounts of data from multiple sources. This means that the data is cleaned, transformed, and integrated before it is stored in the data warehouse, which ensures that the data is accurate and consistent
• Faster Data Access: Data warehouses are designed for fast query performance, which means that users can access and analyze the data quickly and easily. This is especially important for business intelligence activities, such as reporting and data visualization.
• Better Decision Making: Data warehouses provide a single source of truth for an organization’s data, which allows for more accurate and consistent reporting and analysis. This means that organizations can make better, data-driven decisions, and gain a competitive advantage in their industry.

Data warehouses can be used in a variety of industries, including:

• Marketing: Data warehouses can be used to store and analyze customer data, such as purchase history, demographics, and preferences. This allows marketing teams to better understand their customers and create targeted marketing campaigns. The use cases of Data for Marketing are numerous and valuable.
• Product Management / Development: Data warehouses can be used to store and analyze product data, such as sales, customer feedback, and product usage. This allows product development teams to better understand how their products are performing and make data-driven decisions about product improvements and new product development. If you want to learn more about how to use data as a Product Manager, Sololearn is for you.
• Finance: Data warehouses can be used to store and analyze financial data, such as revenue, expenses, and profits. This allows finance teams to better understand the financial performance of the organization and make data-driven decisions about budgeting and forecasting. If you want to make the most of your Excels, budgets, forecasts, or other financial data, knowing how to use data is key if you work in Finance.
• Healthcare: Data warehouses can be used to store and analyze patient data, such as medical history, treatment plans, and outcomes. This allows healthcare providers to better understand their patients and provide more personalized and effective care.

These are just a few examples of how data warehouses can be used in different industries. By using a data warehouse, organizations can improve data quality, access data faster, and make better decisions, which can lead to improved business performance and a competitive advantage in their industry.

5. How does a Data Warehouse work?

One of the key principles of a Data Warehouse is a process known as Extract. Transform. Load (more commonly known by its acronym, ETL). This is the core process for working with all the raw information that comes from different sources and ends up in a Data Warehouse (and sometimes a Data Lake) in a much more organized and clean manner. But…what does each phase of ETL include?

• Extraction: This is the process of collecting data from different sources, such as databases, files, or web services. The data can be structured, which means that it has a predefined format and organization, or unstructured, which means that it does not have a predefined format and organization. For example, a structured data source could be a spreadsheet with customer information, and an unstructured data source could be a social media post with customer feedback.

• Transformation: This is the process of cleaning, transforming, and integrating the data from different sources. The data is cleaned to remove any errors, inconsistencies, or duplicates. The data is transformed to match the format and structure of the data warehouse. The data is integrated to combine data from different sources into a single, consistent data set. For example, the data from the spreadsheet and the social media post could be cleaned, transformed, and integrated to create a single data set with customer information and feedback.

• Loading: This is the process of loading the data into the data warehouse. The data is loaded into tables, which are collections of data organized by rows and columns. The tables are organized into schemas, which are groups of tables that share a common theme or purpose. The schemas are organized into layers, which are levels of abstraction or detail of the data. For example, the data set with customer information and feedback could be loaded into a table called Customer, which belongs to a schema called Marketing, which belongs to a layer called Business. 

Beyond the ETL process, it is crucial how we provide access to the information that we finally have in a structured and organized manner in the Data Warehouse. This is known as “Data Access”. It is not a part of the ETL process itself, which is focused on transforming “raw” information into something more easily consumable. However, it is still vital to fully leverage the data stored in the Data Warehouse.

• Data Access: This is the process of accessing and analyzing the data in the data warehouse. The data is accessed by using queries, which are requests for specific information or calculations from the data. The queries are written in a language called SQL, which stands for Structured Query Language. The queries are executed by a software called a query engine, which processes the queries and returns the results. The results are presented in a format called a report, which can be a table, a chart, a dashboard, or any other visual representation of the data. For example, a query could be written to find out the average customer satisfaction score for a product, and the result could be presented in a bar chart. If you want to learn more about queries and how to use them, you can check our SQL for newbies article

6. What do you need to know to start working with a DataWarehouse?

To start working with a data warehouse, you need to have some basic knowledge and skills in the following languages:

• SQL: This is the language used to access and analyze the data in the data warehouse. You need to know how to write queries, such as SELECT, INSERT, UPDATE, and DELETE, and how to use functions, such as COUNT, SUM, AVG, and MAX. ​​If it sounds complicated to you, don’t worry. You can always learn SQL in a simple and self-paced way.
• Python: This is a programming language that is widely used in data science and data engineering. You need to know how to use Python to extract, transform, and load data, and to perform data analysis and data visualization. If you think Python is only for privileged minds like Leonardo da Vinci, that’s not true. Thousands of people are learning Python with this beginner’s course.
• R: This is a programming language that is specifically designed for data analysis and data visualization. You need to know how to use R to explore, analyze, and interpret the data in the data warehouse, and to create and customize visualizations. If you’ve made it this far, you’ll know that R, unlike what some people may think, is a language that anyone can learn with love and dedication. How? With R courses like this one.