Paranoid

Paranoid is a project providing soft delete capabilities

Paranoid provides an easy mechanism for Ecto-driven projects to soft delete records in the database. This makes for easy recovery in case of accidental deletion or to simply retain data.

Installation

To install simply add paranoid to your dependencies

Update mix.exs by adding Paranoid.

def deps() do
  [
    {:paranoid, "~> 0.1.4"}
  ]

Once installed, a module must be created similar to the following.

defmodule MyApp.Paranoid do
  use Paranoid.Ecto, repo: MyApp.Repo
end

This will become the primary method of interacting with the Ecto repo.

Setting up modules for soft delete

In order to support soft delete, each module requires a migration, an instance of the use macro, and updating the schema to include a deleted_at utc_datetime.

Migration

Paranoid works by considering any non-null deleted_at timestamp to be "deleted". This migration adds this column.

alter table(:your_table) do
  add :deleted_at, :utc_datetime
end

Module Updates

Paranoid makes available changesets for soft deleting and recovery of records. Leveraging use, we bring in these functions and make them overridable for any special use cases a project might have.

  use Paranoid.Changeset

In order to leverage the newly added field, the field must be added to your schema.

field(:deleted_at, :utc_datetime)

Deleting Records

Deleting records is as simple as calling MyApp.Paranoid.delete(struct). If the given module has deleted-at as a column, it will be soft deleted. If it does not, it will simply delete the record.

Retrieving Soft Deleted Records

Backups are only as good as their recovery. To retrieve soft deleted records, there are two steps.

• Retrieve the deleted record
• Undelete the record

# retrieve soft deleted user by adding opts of `include_deleted: true`
user = MyApp.Paranoid.get(MyApp.User, 1, include_deleted: true)

# undelete! the user by setting the deleted_at timestamp to nil
MyApp.Paranoid.undelete!(user)

Leveraging MyApp.Paranoid, an application can call any of the available Ecto.Repo functions. These will respect the deleted_at flag wherever appropriate. Additionally, these functions will retrieve soft deleted records when the option include_deleted is present.

License

Paranoid is free software and distributed under the MIT license. More information can be found in the LICENSE file.

About Echobind

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