Tag: Database Constraints

5 Examples of a UNIQUE Constraint in a Relational Database

5 Examples of a UNIQUE Constraint in a Relational Database UNIQUE constraints help guarantee your data model integrity. This article walks you through 5 examples of UNIQUE constraints in a relational database. Relational databases allow us to define different kinds of constraints (like UNIQUE) to implement integrity rules and ensure that data complies with them. UNIQUE constraints guarantee that no duplicate information is entered in a column (or that no set of columns has the same combination of values).

What Are the Different Types of Database Constraints?

Database constraints are a key feature of database management systems. They ensure that rules defined at data model creation are enforced when the data is manipulated ( inserted, updated, or deleted) in a database. Constraints allow us to rely on the database to ensure integrity, accuracy, and reliability of the data stored in it. They are different from validations or controls we define at application or presentation layers; nor do they depend on the experience or knowledge of the users interacting with the system.

What Is a Foreign Key?

What is a foreign key constraint? Why is it important in relational databases? Find out all about foreign keys in this article. A foreign key is a concept that is often used in relational databases. It is a way to create a link between two different tables. A foreign key is a field that refers to another table‘s primary key. Look at the example below: each player is a member of one team.

Database Constraints in SQL Server and How to Model Them in Vertabelo

Database design – including where and how to use constraints – is essential to the correct function of your database. To properly implement database constraints in SQL Server, you must understand all the requirements and execute them accordingly. How would you do this? This article will explain it in detail! To design your database, you need a database blueprint, database constraints, indexes, database design software like Vertabelo – and more.

Constraints in MySQL and How to Model Them in Vertabelo

Before you do anything, you start with designing the database. It includes columns, tables, and relationships among them, as well as constraints. Database constraints play a crucial role in that they let you prevent any undesired data from being stored in a column or table. Let’s see how to make use of database constraints in MySQL. In this article, we’ll go through all database constraints available in a MySQL database:

Constraints in PostgreSQL and How to Model Them in Vertabelo

Database constraints allow you to give a certain shape to your data, tables, and columns. Are you planning to use PostgreSQL as your database? Check out what PostgreSQL constraints can do! In this article, we will go over PostgreSQL’s database constraints and see how to model them in Vertabelo. For each of the constraints, I’ll provide: A definition of the constraint. A usage example. Instructions on how to model the constraint in Vertabelo.

Database Constraints: What They Are and How to Define Them in Vertabelo

Database constraints help us keep our data clean and orderly. Let’s look at the most common database constraints and how to conveniently define them in Vertabelo. It’s a common practice to set rules for the data in a database. Thanks to these rules, you can avoid incorrect data in a column, e.g. a text string in an Age column or a NULL in a Name column. In this article, we’ll dive into SQL’s database constraints: PRIMARY KEY, FOREIGN KEY, NOT NULL, UNIQUE, DEFAULT, and CHECK.

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