Domains in PostgreSQL

Domains in PostgreSQL are essentially user-defined data types that can be created using the CREATE DOMAIN command. These custom data types allow you to apply constraints and validation rules to columns in your tables by defining a set of values that are valid for a particular attribute or field. This ensures consistency and data integrity within your relational database.

To create a custom domain, you need to define a name for your domain, specify its underlying data type, and set any constraints or default values you want to apply. Domains in PostgreSQL are a great way to enforce data integrity and consistency in your relational database. They allow you to create custom data types based on existing data types with added constraints, default values, and validation rules. By using domains, you can streamline your database schema and ensure that your data complies with your business rules or requirements.