How to set up mgm with a custom MongoDB connection string?

Use mgm.SetDefaultConfig with options.Client().ApplyURI, as shown in the README's initialization example. For non-default connections, implement the CollectionGetter interface to return a custom collection from another database or client.

mgm vs the official Mongo Go Driver: which is better for my Go project?

Choose mgm if you want reduced boilerplate, built-in hooks, and easier aggregations; opt for the official driver if you need maximum control, performance tuning, or are working on a low-level system. mgm builds on the driver, so you can mix approaches if necessary.

How to add validation before saving a document in mgm?

Implement the Creating or Saving hook in your model, validate fields, and return an error to prevent insertion—the README provides an example validating page count. Remember to call the default hooks if overriding to maintain timestamp updates.

Does mgm support indexing or schema migrations?

No, mgm focuses on ODM operations and doesn't include tools for index creation or schema migrations. You'll need to handle indexes separately using the underlying Mongo Go Driver or external migration libraries.

How to handle pagination with mgm queries?

Use SimpleFind with bson.M filters and manually apply skip and limit parameters, as mgm lacks built-in pagination helpers. You can chain sorting and limiting based on your use case, similar to raw driver queries.

Can I use mgm with MongoDB Atlas or cloud deployments?

Yes, mgm is compatible with any MongoDB deployment including Atlas. Set the connection URI in mgm.SetDefaultConfig to your Atlas cluster, ensuring authentication and network settings are configured correctly, as with the official driver.

mgm — Fast MongoDB ODM for Go

What is mgm?

Mongo Go Models (mgm) is a MongoDB Object-Document Mapper (ODM) for the Go programming language. It provides a higher-level abstraction over the official Mongo Go Driver, simplifying tasks like model definition, CRUD operations, and complex queries. It solves the problem of verbose and repetitive MongoDB code by offering a clean, intuitive API with built-in features like hooks, automatic timestamps, and easy aggregation.

Target Audience

Go developers building applications with MongoDB who want to reduce boilerplate code and simplify database interactions. It's ideal for projects requiring structured model management, lifecycle hooks, and complex querying without sacrificing driver compatibility.

Value Proposition

Developers choose mgm because it combines the performance and reliability of the official Mongo Go Driver with a developer-friendly ODM layer. Its unique selling points include built-in hooks for custom logic, predefined MongoDB operators to avoid hardcoding, and seamless integration for transactions and aggregations.

Mongo Go Models (mgm) is a fast and simple MongoDB ODM for Go (based on official Mongo Go Driver)

Use Cases

Best For

Building Go web applications with MongoDB as the backend database
Reducing boilerplate code for MongoDB CRUD operations in Go
Implementing model lifecycle hooks (e.g., validation, logging) in Go
Simplifying complex MongoDB aggregations and queries in Go
Managing database transactions with MongoDB in Go applications
Structuring MongoDB models with automatic timestamps and IDs

Not Ideal For

Projects requiring raw, unabstracted access to the Mongo Go Driver for fine-grained query optimization or custom driver features
Teams building applications with multiple database backends that need a database-agnostic data layer or ORM
Performance-critical systems where the overhead of an ODM's reflection and additional method calls could impact latency or throughput

Pros & Cons

Pros

Lifecycle Hooks

Supports hooks like Creating, Updating, and Deleting for custom logic such as validation or logging, reducing boilerplate—the README shows how to validate page count in a Creating hook.

Aggregation Simplification

Provides builder packages and predefined operators (e.g., operator.Gt) to make complex MongoDB aggregations more readable and less error-prone than hardcoded strings, as demonstrated in the aggregation examples.

Automatic Timestamps

DefaultModel automatically adds and manages created_at and updated_at fields, ensuring consistent timestamping across documents with minimal setup, highlighted in the model definition section.

Transaction Integration

Offers built-in functions like mgm.Transaction() to easily run ACID transactions with MongoDB, leveraging the driver's transaction support without verbose code, as shown in the transactions section.

Cons

Hook Invocation Burden

Defining custom hooks requires manually calling parent DefaultModel hooks (e.g., model.DefaultModel.Creating(ctx)), adding complexity and risk of errors if overlooked, as noted in the hooks documentation.

Abstraction Limitations

As a wrapper over the official driver, mgm may lag in supporting the latest MongoDB features or introduce debugging challenges, and its abstraction can obscure direct driver control when needed for advanced use cases.

Version Constraints

Requires Go 1.17+ and MongoDB 3.6+, which excludes older projects or environments with legacy dependencies, potentially limiting adoption in enterprise settings with fixed tech stacks.

Frequently Asked Questions

What is mgm?

Target Audience

Value Proposition

Use Cases

Best For

Building Go web applications with MongoDB as the backend database
Reducing boilerplate code for MongoDB CRUD operations in Go
Implementing model lifecycle hooks (e.g., validation, logging) in Go
Simplifying complex MongoDB aggregations and queries in Go
Managing database transactions with MongoDB in Go applications
Structuring MongoDB models with automatic timestamps and IDs

Not Ideal For

Projects requiring raw, unabstracted access to the Mongo Go Driver for fine-grained query optimization or custom driver features
Teams building applications with multiple database backends that need a database-agnostic data layer or ORM
Performance-critical systems where the overhead of an ODM's reflection and additional method calls could impact latency or throughput

Pros & Cons

Pros

Lifecycle Hooks

Supports hooks like Creating, Updating, and Deleting for custom logic such as validation or logging, reducing boilerplate—the README shows how to validate page count in a Creating hook.

Aggregation Simplification

Automatic Timestamps

DefaultModel automatically adds and manages created_at and updated_at fields, ensuring consistent timestamping across documents with minimal setup, highlighted in the model definition section.

Transaction Integration

Offers built-in functions like mgm.Transaction() to easily run ACID transactions with MongoDB, leveraging the driver's transaction support without verbose code, as shown in the transactions section.

Cons

Hook Invocation Burden

Abstraction Limitations

Version Constraints

Requires Go 1.17+ and MongoDB 3.6+, which excludes older projects or environments with legacy dependencies, potentially limiting adoption in enterprise settings with fixed tech stacks.

Frequently Asked Questions

mgm

What is mgm?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?

mgm

What is mgm?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?