How do I set up Atlas with Elixir and PostgreSQL?

Define a Repo module using Atlas.Repo with the Postgres adapter, and provide config functions for different environments, as shown in the README's Repo Configuration section. Then start the repo process in your application, ensuring a test repo is set up for testing.

Atlas vs Ecto: which is better for Elixir projects?

Atlas emphasizes the Repository pattern and custom validations, ideal for strict separation of concerns, while Ecto is more mature with broader features like changesets and migrations. Choose Atlas for experimental or validation-heavy PostgreSQL apps, but Ecto for production-ready, feature-complete needs.

Does Atlas support database migrations?

No, migrations are listed on the roadmap but not yet implemented. You'll need to handle schema changes manually or use external tools, which can be a drawback for evolving databases.

How can I add custom validations in Atlas?

Create custom validator modules using Atlas.Validator or define validation functions in your model, as shown in the example with `lives_in_ohio` that checks state fields. These callbacks integrate seamlessly with the persistence workflow.

Can Atlas handle multiple database connections?

Yes, through the Repository pattern, you can define multiple repos for different connections, but currently limited to PostgreSQL adapters. The configuration allows separate settings per environment, though setup is manual.

Is Atlas ready for production use?

Not recommended for critical production systems due to its work-in-progress status and breaking changes. It's better suited for development or projects where you can tolerate instability and missing features.

atlas — Elixir ORM With Postgres Adapter

What is atlas?

Atlas is an Object Relational Mapper (ORM) for the Elixir programming language, designed to provide a structured and flexible way to interact with databases. It follows the Repository pattern to decouple persistence logic from business logic, enabling robust data management and validation workflows. It currently supports PostgreSQL and includes features like schema definitions, a composable query builder, and built-in validations.

Target Audience

Elixir developers building applications that require structured database interactions with a focus on separation of concerns and data integrity. It is particularly suited for projects that benefit from the Repository pattern to manage multiple database connections and complex validation workflows.

Value Proposition

Developers choose Atlas for its strict adherence to the Repository pattern, which cleanly separates persistence from business logic, and its flexible validation system with custom callback support. Its composable query builder and automatic generation of field accessors and finders reduce boilerplate code while maintaining clarity.

Object Relational Mapper for Elixir

Use Cases

Best For

Elixir applications requiring a clean separation between database logic and business logic using the Repository pattern.
Projects that need built-in and custom validation callbacks to enforce complex data integrity rules.
Teams building PostgreSQL-backed Elixir applications with a need for composable, chainable query interfaces.
Developers looking for an ORM that automatically generates field accessors and 'with_[field]' finder functions to reduce manual coding.
Applications that plan to support multiple database adapters in the future, as indicated by the roadmap.
Scenarios where data models require declarative schema definitions with explicit primary key and field typing.

Not Ideal For

Projects requiring immediate support for SQL joins or model relationships (e.g., has_many, belongs_to).
Applications that need to connect to databases other than PostgreSQL.
Production systems where API stability is critical due to expected breaking changes.

Pros & Cons

Pros

Repository Pattern Implementation

Cleanly separates persistence logic from business logic, enabling multiple database connections and validation workflows, as demonstrated in the persistence examples with different validator modules.

Flexible Validation System

Supports built-in validators and custom callbacks, allowing complex data integrity checks like the Manager validator that enforces age restrictions beyond base model rules.

Composable Query Builder

Provides a chainable interface for building queries, shown in examples where conditions and ordering can be combined, making code readable and reusable.

Auto-generated Accessors and Finders

Automatically creates field accessors and `with_[field]` finder functions, reducing boilerplate, with the ability to override for custom behavior as in the email upcasing example.

Cons

Incomplete Feature Set

Lacks essential ORM features like joins, relationships, and migrations, which are only on the roadmap, limiting its usefulness for advanced database operations.

Breaking Changes Expected

Explicitly labeled as a work in progress, so API changes are likely, posing maintenance risks for projects that depend on stability.

Limited Database Support

Currently only supports PostgreSQL, with other adapters planned but not available, restricting flexibility in multi-database environments.

Manual Configuration Overhead

Requires defining Repo configuration for each environment manually in code, which can be tedious and error-prone compared to configuration file-based systems.

What is atlas?

Target Audience

Value Proposition

Use Cases

Best For

Elixir applications requiring a clean separation between database logic and business logic using the Repository pattern.
Projects that need built-in and custom validation callbacks to enforce complex data integrity rules.
Teams building PostgreSQL-backed Elixir applications with a need for composable, chainable query interfaces.
Developers looking for an ORM that automatically generates field accessors and 'with_[field]' finder functions to reduce manual coding.
Applications that plan to support multiple database adapters in the future, as indicated by the roadmap.
Scenarios where data models require declarative schema definitions with explicit primary key and field typing.

Not Ideal For

Projects requiring immediate support for SQL joins or model relationships (e.g., has_many, belongs_to).
Applications that need to connect to databases other than PostgreSQL.
Production systems where API stability is critical due to expected breaking changes.

Pros & Cons

Pros

Repository Pattern Implementation

Cleanly separates persistence logic from business logic, enabling multiple database connections and validation workflows, as demonstrated in the persistence examples with different validator modules.

Flexible Validation System

Supports built-in validators and custom callbacks, allowing complex data integrity checks like the Manager validator that enforces age restrictions beyond base model rules.

Composable Query Builder

Provides a chainable interface for building queries, shown in examples where conditions and ordering can be combined, making code readable and reusable.

Auto-generated Accessors and Finders

Automatically creates field accessors and `with_[field]` finder functions, reducing boilerplate, with the ability to override for custom behavior as in the email upcasing example.

Cons

Incomplete Feature Set

Lacks essential ORM features like joins, relationships, and migrations, which are only on the roadmap, limiting its usefulness for advanced database operations.

Breaking Changes Expected

Explicitly labeled as a work in progress, so API changes are likely, posing maintenance risks for projects that depend on stability.

Limited Database Support

Currently only supports PostgreSQL, with other adapters planned but not available, restricting flexibility in multi-database environments.

Manual Configuration Overhead

Requires defining Repo configuration for each environment manually in code, which can be tedious and error-prone compared to configuration file-based systems.

atlas

What is atlas?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?

atlas

What is atlas?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?