Ecto/Changesets

Ecto/Changesets

The "Ecto/Changesets" module in Elixir's Ecto library is a powerful tool for working with database changes. Changesets provide an easy and flexible way to manipulate and validate data before it is inserted or updated into the database.

What are Changesets?

Changesets are data structures that store the changes made to a particular schema or model. They encapsulate all the modifications made to the data and provide functions to validate and transform it. By using changesets, you can separate the concerns of data manipulation and data validation.

Creating Changesets

To create a changeset, you need to define a schema. The schema represents the structure of your data in Elixir code. Once the schema is defined, you can use the `cast/3` function to populate a changeset with the data you want to modify. The `cast/3` function takes the changeset, the data to cast, and a list of allowed fields.

Modifying Changesets

Changesets provide a range of functions to modify the data. You can use the `put_change/3` function to update individual fields in the changeset or use `change/3` to replace the entire set of changes. Additionally, `put_assoc/4` allows adding or modifying associations within the changeset.

Validating Changesets

Changesets also include built-in validation capabilities. The `validate_required/3` function ensures that specific fields are present, while `validate_inclusion/4` checks if the field value is allowed within a given set of options. Other validation functions are available for various types of validation.

Applying Changesets

Once you have created and modified your changeset, you can apply it to the database using the `Repo` module from Ecto. The `Repo.insert/2` function enables the insertion of new data into the database, while `Repo.update/2` allows updating existing data using the changeset.

Conclusion

Ecto/Changesets provide a flexible and powerful way to work with database changes in Elixir. They allow you to manipulate and validate data before it is persisted to the database, ensuring its integrity and consistency. Understanding and utilizing changesets in your Elixir projects can greatly enhance your data manipulation capabilities.

For more information, please refer to the Ecto documentation.

See Also

• Ecto/Schema
• Ecto/Query