Data Mart

What is a Data Mart?

A Data Mart is a subset of a data warehouse, designed to serve the specific needs of a particular business unit, department, or set of users within an organization. It focuses on a specific subject area or domain, such as sales, marketing, finance, or human resources, and provides users with access to relevant data for analytical and reporting purposes. Data marts are optimized to deliver fast data retrieval and analysis, making them an essential component of an organization's decision-support system.

Purpose and Role of Data Marts

The primary purposes and roles of data marts include:

  • Targeted Data Access: Providing users with focused and streamlined access to the data relevant to their specific functional area, without the complexity of navigating a full data warehouse.
  • Improved Performance: Since data marts contain a smaller, more focused subset of data, they can significantly improve query performance and analysis speed for end-users.
  • Simplified Reporting and Analysis: Facilitating easier and more efficient reporting and analysis by offering data that is already tailored to the specific needs and context of the department or business unit.
  • User Empowerment: Empowering non-technical users to perform their data analysis and reporting, reducing reliance on IT departments for generating reports and insights.

Types of Data Marts

Data marts can be categorized based on their method of creation:

  • Dependent Data Marts: These are created from an existing data warehouse and rely on the data warehouse for data feeds. The extraction, transformation, and loading (ETL) processes are managed at the data warehouse level.
  • Independent Data Marts: These are developed without direct reliance on a central data warehouse, often using data from operational systems or external sources. Independent data marts require their ETL processes.

Key Components of Data Marts

  • Database: The core component where data is stored. The database is designed to optimize data retrieval and analysis.
  • ETL Tools: Used to extract data from various sources, transform it into a consistent format, and load it into the data mart.
  • Metadata: Descriptive information about the data within the data mart, including data sources, transformations applied, and data definitions.
  • User Interface: Tools and applications that allow users to access, analyze, and report on the data contained in the data mart.

Developing a Data Mart

The process of developing a data mart typically involves the following steps:

  • Requirements Gathering: Understanding the specific needs and objectives of the end-users and the business unit the data mart will serve.
  • Design: Outlining the architecture of the data mart, including the schema design, which can be star schema, snowflake schema, or another model suited to the data and queries.
  • Data Sourcing: Identifying and accessing the data sources that will feed into the data mart.
  • ETL Process: Extracting data from the sources, transforming it into a suitable format, and loading it into the data mart.
  • Implementation and Testing: Setting up the data mart, followed by rigorous testing to ensure data integrity and query performance.
  • Deployment and Training: Making the data mart available to users and providing necessary training on how to use it effectively.

Challenges and Considerations

  • Data Consistency: Ensuring data consistency and accuracy across data marts and the broader data warehouse environment.
  • Scalability: Designing data marts to be scalable as the volume of data and the number of users grow.
  • Security: Implementing robust data security measures to protect sensitive information and comply with regulations.


Data marts play a crucial role in making data accessible and useful for specific business units within an organization, facilitating efficient, targeted data analysis and decision-making. By providing a focused view of data, data marts enable users to gain insights relevant to their specific domain, improving performance and productivity.

See Also

A Data Mart is a subset of a data warehouse that is focused on a specific business line or team, such as sales, marketing, or finance. Data marts are designed to meet the specific needs of a particular group of users. They are smaller, more focused databases designed for quick access to relevant data, enabling users to make more informed decisions based on data specific to their functional area.

  • Data Warehouse: Explaining the central repository of integrated data from one or more disparate sources. Data warehouses store current and historical data and are used for creating trending reports for senior management reporting such as annual and quarterly comparisons.
  • ETL (Extract, Transform, Load): Covering the process used to gather data from various sources, transform it into a format that can be analyzed, and load it into a data warehouse or data mart.
  • Business Intelligence (BI): Discussing the technologies, applications, strategies, and practices used to collect, analyze, integrate, and present pertinent business information. BI uses data marts and data warehouses as sources of information.
  • OLAP (Online Analytical Processing): Explaining the approach to swiftly answer multi-dimensional analytical queries. OLAP is often used in data warehousing and data marts for complex calculations, trend analysis, and data modeling.
  • Data Modeling: Covering the process of creating a data model for the data to be stored in a database. This topic is crucial for understanding how data marts are structured to support the business processes they are designed for.
  • Dimensional Modeling: Discussing a data structure technique optimized for data warehousing and data mart applications. Dimensional models are designed to improve data readability and query performance.
  • Star Schema and Snowflake Schema: Explaining two common types of data models used in data marts and data warehouses. The star schema is a simple database design that optimizes querying large datasets. The snowflake schema is a variant of the star schema, with additional normalization.
  • Data Governance: Highlighting the process of managing the availability, usability, integrity, and security of the data in enterprise systems, based on internal data standards and policies that also control data usage.
  • Data Integration: Covering the practices and technologies involved in preparing and combining data from different sources to provide a unified, consistent view that can be stored in a data warehouse or data mart.
  • Master Data Management (MDM): Explaining the technology-enabled discipline in which business and IT work together to ensure the uniformity, accuracy, stewardship, semantic consistency, and accountability of the enterprise’s official shared master data assets.
  • Data Quality: Discussing the importance of accuracy, completeness, and reliability of data within the data mart, including processes for cleaning, validating, and verifying data to ensure it meets the specific needs of its users.
  • Analytics and Reporting Tools: Covering the software tools used to analyze data stored in data marts and create reports, dashboards, and data visualizations to support business decision-making.