database design

What is Database Normal Form?

by

When you’re designing a database, you need some way to organize your data that makes sense. You could just throw everything into one massive table, but that leads to problems pretty quickly. Duplicate data everywhere, weird update issues, and a general mess that’s hard to maintain.

Normal forms give you a framework for organizing data in a way that avoids these problems. They’re a series of rules or guidelines that help you structure your database tables properly.

This process of organizing data according to normal forms is called normalization, and it’s one of the fundamental concepts in relational database design.

Read more

What is Relationship Cardinality?

by

When you’re designing a relational database, you need to define how tables relate to each other. You do this by creating relationships between the tables. Relationship cardinality describes how many records in one table can be associated with records in another table. It’s a fundamental concept that affects how you structure your database and write your queries.

Understanding cardinality helps you avoid design mistakes that lead to data integrity issues, performance problems, or queries that return unexpected results.

Read more

What is a Snowflake Schema?

by

In relational databases, a snowflake schema is a variation of the star schema where dimension tables are normalized into multiple related tables. Instead of keeping all dimensional attributes in a single wide table, you break them down into a hierarchy of tables that branch out like (you guessed it) a snowflake.

It’s basically what happens when you apply database normalization principles to a star schema’s dimension tables while keeping the central fact table intact.

Read more

What is an Attribute in a Database?

by

In database terminology, an attribute is a piece of information that describes an entity. If an entity is a thing you want to store data about, attributes are the specific details you’re storing. They’re the characteristics, properties, or facts that define what you know about each entity.

When you create a relational database, attributes become the columns in your tables. Each attribute represents one type of information you’re tracking.

Read more

What is a Database Entity?

by

In database design, an entity is something you want to store information about. It’s a person, place, thing, event, or concept that matters to your application and has data associated with it that you need to track.

Entities are the building blocks of database design. Before you create tables, write queries, or think about indexes, you need to identify what entities exist in your domain and what information you need to store about them.

Read more

What is a Slowly Changing Dimension?

by

In data warehousing, a slowly changing dimension (SCD) is a dimension table where the attributes change over time, but not very frequently. The term “slowly changing” refers to the fact that these changes happen occasionally (perhaps days, weeks, or months apart) rather than constantly like transactional data.

The challenge is figuring out how to handle these changes while maintaining accurate historical analysis. When a customer moves to a new state or a product gets recategorized, you need a strategy that preserves the integrity of your historical data.

Read more

What is a Dimension Table?

by

In data warehousing and analytics systems, dimension tables provide context for the measurements stored in fact tables. While fact tables contain the numbers you want to analyze, dimension tables tell you what those numbers mean. This could be things like who was involved, what product it was, when it happened, where it occurred, etc.

Basically, dimension tables are the “descriptive” side of dimensional modeling, containing the attributes and characteristics that let you filter, group, and label your data in meaningful ways.

Read more

What is a Fact Table?

by

In data warehousing and analytics databases, a fact table is where you store the actual measurements and metrics of your business. It’s the table that contains the numbers you want to analyze. This could include things like sales amounts, quantities, counts, durations, or any other quantifiable data points.

Fact tables are the foundation of dimensional modeling, the approach most commonly used for organizing data in data warehouses and business intelligence systems.

Read more

What is a Star Schema?

by

If you’ve ever worked with data warehouses or business intelligence systems, you’ve probably encountered star schemas. Perhaps even without realizing it. Star schemas are one of the most common ways to organize data for analytics and reporting.

Star schemas look exactly like their name suggests. They consist of a central table surrounded by related tables, forming a star shape.

Star schemas are designed specifically for querying and analysis rather than transactional operations. They make it easy to slice and dice data in ways that business users actually care about.

Read more

What is Denormalization?

by

If you’ve spent any time working with relational databases, you’re probably well aware of the concept of normalization. This is the process of organizing data in a way that reduces redundancy and maintains consistency. It’s basically SQL Database Design 101. And for good reason.

But sometimes the “right” way to design a database isn’t necessarily the most practical way to run it. Sometimes we need to tweak the thing until we get it performing just right. And sometimes this means deviating from the norm and using a different approach. Denormalization is an example of this.

Read more