Rel Concepts

A set of concept guides explaining key aspects of the Rel language.

Concept Guides cover topics important to developing quality applications in Rel.

List of Concept Guides

Installing Models

Introduces the concept of an "installed source", which is a set of definitions that persist as part of the database. These installed definitions can be reused later in queries, or as building blocks for larger models.

Integrity Constraints

Introduces integrity constraints in Rel. Integrity constraints ensure that data integrity is not affected by data insertion, updates, and other processes.


Introduces the Rel module syntax, where relations can be grouped together as modules, which can be parameterized, combined, and even be used as parameters to other modules.


Demonstrates how to write and successfully use recursive relations. Recursive relations are relations that depend on themselves.


Introduces Rel's support for entities, which are objects that exist independently of their representation in the database, and can be uniquely identified. An entity can be a concrete object, such as a car or a person, or more abstract, such as an organization.

Updating Data

Describes how to persist and update data in a RAI database using the Rel language.