https://github.com/umbrellio/sequel-batches

Sequel extension for querying large datasets in batches
https://github.com/umbrellio/sequel-batches

batches sequel

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Sequel extension for querying large datasets in batches

• Host: GitHub
• URL: https://github.com/umbrellio/sequel-batches
• Owner: umbrellio
• License: mit
• Created: 2018-03-15T13:37:37.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2024-07-01T10:54:03.000Z (3 months ago)
• Last Synced: 2024-07-20T03:53:56.939Z (2 months ago)
• Topics: batches, sequel
• Language: Ruby
• Homepage:
• Size: 44.9 KB
• Stars: 18
• Watchers: 6
• Forks: 2
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.txt
  • Code of conduct: CODE_OF_CONDUCT.md

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README

        
# Sequel::Batches    [![Gem Version](https://badge.fury.io/rb/sequel-batches.svg)](https://badge.fury.io/rb/sequel-batches) [![Build Status](https://travis-ci.org/umbrellio/sequel-batches.svg?branch=master)](https://travis-ci.org/umbrellio/sequel-batches) [![Coverage Status](https://coveralls.io/repos/github/umbrellio/sequel-batches/badge.svg?branch=master)](https://coveralls.io/github/umbrellio/sequel-batches?branch=master)

This dataset extension provides the `#in_batches` method. The method splits dataset in parts and yields it.

Note: currently only PostgreSQL database is supported.

## Installation

Add this line to your application's Gemfile:

```ruby

gem 'sequel-batches'

```

## Usage

In order to use the feature you should enable the extension:

```ruby

DB.extension(:batches)

```

After that the `#in_batches` method becomes available on dataset:

```ruby

User.where(role: "admin").in_batches(of: 4) do |ds|

  ds.delete

end

```

Finally, here's an example including all the available options:

```ruby

options = {

  of: 4,

  pk: [:project_id, :external_user_id],

  start: { project_id: 2, external_user_id: 3 },

  finish: { project_id: 5, external_user_id: 70 },

  order: :desc,

}

Event.where(type: "login").in_batches(**options) do |dataset|

  dataset.delete

end

```

## Options

You can set the following options:

### pk

Overrides primary key of your dataset. This option is required in case your table doesn't have a real PK, otherwise you will get `Sequel::Extensions::Batches::MissingPKError`.

Note that you have to provide columns that don't contain NULL values, otherwise this may not work as intended. You will receive `Sequel::Extensions::Batches::NullPKError` in case batch processing detects a NULL value on it's way, but it's not guaranteed since it doesn't check all the rows for performance reasons.

### of

Sets chunk size (1000 by default).

### start

A hash `{ [column]:  }` that represents frame start for batch processing. Note that you will get `Sequel::Extensions::Batches::InvalidPKError` in case you provide a hash with wrong keys (ordering matters as well).

### finish

Same as `start` but represents the frame end.

### order

Specifies the primary key order (can be `:asc` or `:desc`). Defaults to `:asc`.

## Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/umbrellio/sequel-batches.

## License

The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).