In an SQL database, the primary key is an essential part of any table. Choosing the right primary key for each table requires us to take different factors into consideration if we want to guarantee simplicity, adaptability, and performance. A primary key (PK) is a specific type of database constraint. It guarantees that the column (or columns) that are part of it do not accept NULL values and that the value (or combination of values) entered for each row is unique.
A natural key is used to provide simple, easy-to-remember values (or set of values) that are meaningful to the business as an identifier for each row, rather than using business-agnostic, system-generated values as primary keys for database tables. Before getting into detail about what a natural key is, you might want to read the article “On Keys” to fully understand the concept of keys in a database model and their different types.
A surrogate key is a type of primary key used in most database tables. It provides a simple, system-generated, business-agnostic column. This column is used as an identifier for each row rather than relying on pre-existing attributes. Learn more, including why surrogate keys are widely used, below. Before learning about surrogate keys in detail, consider reading the article “On Keys.” This will help you fully understand the concept of keys in a database model and the different types that exist.
Designing a clear physical data model can be challenging – especially when you don’t stop to consider these eight critical areas. Get our expert tips on creating a better physical model. A physical model is the technical implementation of a logical data model. It has a higher level of detail and is specifically created for a particular database vendor, taking into account that database management system’s technical features and restrictions.
If a picture is worth a thousand words, then entity-relationship diagrams (or ER diagrams) are a priceless way to visually explain the structure and behavior of a software solution. Learn how to make your own ERDs with the Vertabelo online data modeler! The term entity-relationship diagram and its abbreviations ER diagram and ERD are frequently used when designing and implementing databases. What are these entities and relationships we’re diagramming?
Depending on the purpose, we may need to create either a conceptual, logical, or physical data model. Find out the differences and use cases for each one. Data modeling implies identifying and defining entities and their relationships for a business solution. It requires a good understanding of the desired business outcome and is the foundation for creating a robust software solution. The different model types (conceptual, logical, and physical) have different levels of detail and are used at different stages of the software development process.
One-to-many relationships are one of the most common database relationships. If you want to learn when and how to use one-to-many relationships, then this article is a great starting point. You will surely use one-to-many relationships to store information in any relational database, whether you are designing enterprise-level software or just creating a simple database to keep track of your uncle’s stamp collection. A Brief Introduction to the Relational Model Relational databases are a core component of any modern transactional application.