Data lakes vs. data warehouses — what’s the difference, and which do you need?

Professional reviewing data on laptop

In today's data-driven world, businesses are generating and collecting vast amounts of data from a variety of sources. To make sense of this data and derive insights that can drive business success, organizations need a reliable and scalable way to store, process, and analyze it.

Two popular options for storing and analyzing data are data lakes and data warehouses. While both serve as repositories for large amounts of data, they have different architectures, use cases, and benefits.

In this blog post, we'll explore the differences between data lakes and data warehouses and help you determine which approach is best suited for your business needs.

In this post, you’ll learn:

What is a data lake?

A data lake is a centralized repository that allows organizations to store large amounts of raw, unstructured, and structured data in its native format. Data lakes store data in its original format, which can be anything from text and images to videos and social media posts.

Data lakes enable organizations to store vast amounts of data at a lower cost as they use less-expensive storage solutions, such as cloud-based object storage. Data lakes also allow organizations to collect and store data from various sources — including Internet of Things devices, social media platforms, and web analytics — without the need for data processing or transformation.

Data lakes can be used for a wide range of use cases, including big data analytics, machine learning, and data science. With the help of advanced analytics tools and technologies, organizations can extract insights from their data lakes to make informed decisions, improve business operations, and drive innovation.

What is a data warehouse?

A data warehouse is a large, centralized repository of data that is used to support business intelligence activities like data analysis, reporting, and decision-making. Data warehouses are designed to store structured data, which is organized into tables with defined relationships between them.

Unlike a data lake, which stores data in its native format, a data warehouse requires the data to be transformed and structured into a specific schema before it can be loaded. This process involves extracting data from various sources, transforming it into a consistent format, and loading it into the data warehouse.

Data warehouses are designed to support complex queries and reporting, and they typically have a more rigid schema compared to data lakes. They also often use specialized tools and technologies for faster, more efficient analysis of large volumes of data.

Data warehouses are commonly used in industries such as finance, healthcare, and retail — where the analysis of large amounts of data is critical for business success. By providing a single source of truth for data, data warehouses help organizations make better-informed decisions, improve operational efficiency, and gain a competitive edge.

Data lakes vs. data warehouses

While data lakes and data warehouses are similar in that they both can store large amounts of data, there are some key differences that you should be aware of. This table provides a comparison between the two , so you’ll get a better understanding of which will work best for your specific needs.

: Data lakes vs. data warehouses

Data lake
Data warehouse
1. Data storage
Data lakes store data in its original (or raw) format, which provides more flexibility for how data is used in the future.
Data warehouses store data in a predefined schema, so it’s ready for analysis , based on specific business needs.
2. Users
Data lakes are used primarily by data scientists for big data analytics, machine learning, and IoT purposes.
Data warehouses are used primarily by business professionals for business intelligence, reporting, and data analysis applications.
3. Schema position
Schema on read. In a data lake, the schema of the data can be inferred when it’s read.
Schema on write. When data is written into a data warehouse, a schema needs to be defined.
4. Cost
Data lakes typically cost less per unit of storage than data warehouses.
Data warehouses have higher costs per unit of storage than data lakes.
5. Data processing

Raw data in data lakes must be processed before it can be used for analytics.

ELT (Extract, Load, Transform). This process extracts data from storage and only modifies or structures the data when necessary.

Data in data warehouses has been preprocessed for analytics.

ETL (Extract, Transform, Load). This process extracts data from storage and then cleans and structures the data so it can be used for business analytics or other purposes.

6. Supported data types
Data lakes support structured, semi-structured, and unstructured data.
Data warehouses support data that is structured and processed.

Which one is right for your business?

When deciding whether to use a data lake or a data warehouse, you should consider a few key factors including the types of data you need to store and analyze, your business objectives, and your budget and technical capabilities.

Here are some questions businesses can ask to help guide their decision-making:

  1. What types of data do we need to store and analyze? If a business is collecting structured data from a few sources with a well-defined schema, a data warehouse is probably the best choice. If the data is unstructured or semi-structured because it’s coming from a range of sources — or if the schema may change often — a data lake is likely the better fit.
  2. What are our business objectives? If the goal is to support business intelligence and reporting, a data warehouse is probably the better choice. If the goal is to enable more advanced analytics, such as machine learning or data science, a data lake may be more appropriate.
  3. What are our budget limitations and technical capabilities? Data warehouses can be more expensive to set up and maintain than data lakes. Data lakes can be more cost-effective and easier to set up, but they may require more advanced analytics tools and techniques to extract insights from the data.
  4. Can we use both? In some cases, a hybrid approach that combines both data lakes and data warehouses may be the best option. For example, businesses can use a data lake to store raw data and perform exploratory analysis , and then move the data to a data warehouse for more structured reporting and analysis.

Ultimately, the decision of whether to use a data lake or a data warehouse — or both — depends on the specific needs and objectives of the business, as well as the technical capabilities and resources available.

Get started with a data lake or data warehouse platform

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