data modeling

What is a database schema and why does it matter?

If you're responsible for managing a database or delivering value with data through applications like business analytics, understanding database schema is essential. The schema defines the structure of a database and outlines the tables and fields, including the relationships between them, and other data elements necessary to accurately access and update information stored within. 

Not only does having an in-depth understanding of database schemas allow for efficient development of data platforms, including a cloud data platform, but it can also help pinpoint potential issues like performance bottlenecks that can impact system operations, lead to down time, and hinder ROI from investments in data. In this comprehensive guide, we will break down everything you need to know about database schemas: what they are, how they work, types, the relationship between database schemas and database management systems, and what to consider when designing a database schema.

The definition of database schema

A database schema is a blueprint of the logical layout of a database, outlining how data is organized and structured. It describes various objects within the database, such as tables, columns, views, indexes, and stored procedures.

You can think of it as the skeleton, providing the framework and scaffolding for how the various data elements relate and work together. The primary purpose of creating a database schema is to ensure the integrity of the data stored in the database, so it can confidently be used by the broader business for applications such as business intelligence. Having the right schema is an essential element of data modeling, especially for organizations that rely on data to drive multiple parts of their business. 

The database schema is defined in the form of a table diagram or an entity-relationship diagram (ERD). A table diagram illustrates the structure of each table within the database, whereas an ERD outlines how different tables or objects relate to one another. These diagrams are used to define the structure of data within the database, star schema or snowflake schema,  and ensure consistency in the way it is stored. 

The importance of a database schema lies in its ability to outline the logical layout of a database and keep data organized. It helps users identify which tables, columns, and relationships exist between objects, enabling them to efficiently access, query, or modify data. A well-defined database schema also improves the accuracy of data, as it reduces the chances of incorrect information being entered into the database. Additionally, it helps to ensure that users are not able to access or modify sensitive information which they should not have access to. The most successful organizations leverage tools across the modern data stack that make building and leveraging these schemas incredibly seamless.  

3 most common types of database schemas

Examples of a conceptual model design, logical model design, and a physical model design.

1. Conceptual schema

A conceptual schema is a high-level presentation of the structure and relationships in a database. It describes the main concepts of data, as well as how they are related to each other. A conceptual schema does not go into detail about specific objects such as tables, views, and columns; instead, it focuses on abstract concepts and how they relate to one another.

The purpose of a conceptual schema is to provide an overall view of the structure and relationships in a database. It helps users understand the underlying structure, as well as identify any potential problems or inconsistencies before they make their way into data applications or impact insights derived from analytics. This type of schema can also be used by database developers to design more detailed schemas.

2. Logical schema

A logical schema is an intermediate level of detail between a conceptual and physical database design. It provides a more detailed description of the data, including specific objects such as tables and columns. A logical schema outlines the structure and relationships between various entities within a database, as well as how data is stored in the tables.

The purpose of a logical schema is to ensure that data is logically organized and stored efficiently. It helps users identify the relationships between entities, providing even more ways than a conceptual schema to identify issues in the schema early. Logical schemas are particularly useful for developers because they provide a better understanding of how data is structured and can be used to design even more detailed schemas as needed.

3. Physical schema

A physical schema is the most detailed level of a database design. It describes how data is physically stored in the system and outlines specific objects such as tables, columns, indexes, and views. A physical schema also includes information about the storage media used for each table, such as a cloud data warehouse or data lakehouse, as well as any constraints or triggers associated with the data or storage methodology .

The purpose of a physical schema is to provide a detailed description of how data is stored in the system. It helps database developers determine which storage media should be used for each table and ensure that data is logically organized. Additionally, it can help identify any potential issues or inconsistencies before they occur. By having an established physical schema, developers can ensure that data is stored efficiently and easily retrieved when needed.

The relationship between database schema and database management systems

The structure and relationships of a database schema are reflected in the design of a database management system (DBMS). Data management systems act as an interface between users and the data stored in a database, allowing them to access and manipulate information. For users to effectively use a DBMS, it must be designed to incorporate the database schema. This requires a thorough understanding of the underlying structure, relationships, and data types present in the schema.

Having a well-designed database schema can also provide many advantages to users. A properly designed schema helps to ensure data accuracy and integrity, as well as reduce redundancy and enhance the performance of the system. Additionally, it makes it easier for developers to understand the underlying structure of the database, allowing them to make improvements more quickly. Lastly, a well-designed schema makes it easier for users to access and manipulate data, as they will understand its structure more easily. This is especially critical for organizations that want to bring analytics to a wide set of users through self-service or data visualization. Ultimately, a well-designed database schema can improve the efficiency of any system, and is a critical step to building a culture and business that operates based on data.

What to consider when designing your database schema

When designing a database schema, there are several factors to consider. First, it is important to understand the data that will be stored in the system and determine the structure of the tables and columns accordingly. Additionally, it is important to identify any relationships between entities within the system and ensure that they are properly represented in the design. Lastly, it is important to consider any constraints or triggers that may be necessary for maintaining data integrity. 

In addition to the above considerations, there are also best practices to follow when designing a database schema. It is important to ensure that tables and columns are properly named, as this will make them easier to understand. Additionally, it is important to maintain consistency when designing the schema and avoid redundant data where possible. 

Lastly, it is important to test the database schema thoroughly to ensure that it meets the needs of users. Building database schemas is only valuable when they can be leveraged by the business to improve efficiencies, capitalize on opportunities, or reduce risk. The most successful organizations, therefore, don’t think about database schemas in isolation, but as part of their larger analytics strategy, in which the value of these schemas is exposed to decision makers at all levels through self-service business intelligence

By following these best practices, developers can ensure that their database schemas are well-designed and optimized for performance.

Leverage the power of data-driven decision making

Database schema is an essential element when following effective database management best practices. Without it, running queries and getting accurate results become virtually impossible. Well-developed database schemas can save you time and energy when it comes to future analyses and project development. And these schemas are exposed to actual business users through the right analytics tool, organizations can begin realizing real, tangible business value. 

ThoughtSpot offers great resources for businesses looking to leverage the power of data-driven decision making—from self-service reporting needs to advanced analytics projects—that let you take advantage of the right data schema for your business. Whether you're managing databases or querying large datasets, utilizing ThoughtSpot's innovative technology can make all the difference for teams accustomed to using traditional business intelligence tools.

Sign up for your free trial today and realize the power of significantly improved data analysis processes with powerful insights derived from your own databases.