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Real upsert for PostgreSQL 9.5+ and Rails 5.2+ / ActiveRecord 5.2+. Uses ON CONFLICT DO UPDATE.

Main points

  • Does upsert on a single record using ON CONFLICT DO UPDATE
  • Updates timestamps as you would expect in ActiveRecord
  • For partial upserts, loads any existing data from the database


  • PostgreSQL 9.5+ (that's when UPSERT support was added; see Wikipedia's PostgreSQL Release History)
  • ActiveRecord >= 5.2
  • Ruby MRI, with the pg gem
  • JRuby is currently not supported


This library was written at a time in history when Rails did not support any #upsert method.

Instead of using this library, if you are using a current version of Rails, you may want to use its #upsert. You may want to investigate how newer PostgreSQL versions support MERGE statement.

NB: Releases to avoid

Due to a broken build matrix, v0.9.2 and v0.9.3 are incompatible with Rails < 5.2.1. v0.9.4 fixed this issue.

Supported Rails versions

This library is compatible with all major Rails versions covered by the Rails "Severe Security Issues" maintenance policy.

Supported Ruby versions

This library may be compatible with older versions of Ruby, however we only run automated tests using the officially supported Ruby versions.


Add this line to your application's Gemfile:

gem 'active_record_upsert'

And then execute:


Or install it yourself as:

gem install active_record_upsert



Use ActiveRecord.upsert or ActiveRecord#upsert. ActiveRecordUpsert respects timestamps.

class MyRecord < ActiveRecord::Base

MyRecord.create(name: 'foo', wisdom: 1)
# => #<MyRecord id: 1, name: "foo", created_at: "2016-02-20 14:15:55", updated_at: "2016-02-20 14:15:55", wisdom: 1>

MyRecord.upsert(id: 1, wisdom: 3)
# => #<MyRecord id: 1, name: "foo", created_at: "2016-02-20 14:15:55", updated_at: "2016-02-20 14:18:15", wisdom: 3>

r = 1) = 'bar'
# => #<MyRecord id: 1, name: "bar", created_at: "2016-02-20 14:15:55", updated_at: "2016-02-20 14:18:49", wisdom: 3>


If you need to specify a condition for the update, pass it as an Arel query:

MyRecord.upsert({id: 1, wisdom: 3}, arel_condition: MyRecord.arel_table[:updated_at].lt(

The instance method #upsert can also take keyword arguments to specify a condition, or to limit which attributes to upsert (by default, all changed attributes will be passed to the upsert):

r = 1) = 'bar'
r.color = 'blue'
r.upsert(attributes: [:name], arel_condition: MyRecord.arel_table[:updated_at].lt(
# will only update :name, and only if the record is older than 1 day;
# but if the record does not exist, will insert with both :name and :colors

Create with specific Attributes

If you want to create a record with the specific attributes, but update only a limited set of attributes, similar to how ActiveRecord::Base.create_with works, you can do the following:

existing_record = MyRecord.create(id: 1, name: 'lemon', color: 'green')
r = 1, name: 'banana', color: 'yellow')
r.upsert(attributes: [:color])
# => #<MyRecord id: 1, name: "lemon", color: "yellow", ...>

r = 2, name: 'banana', color: 'yellow')
r.upsert(attributes: [:color])

# => #<MyRecord id: 2, name: "banana", color: "yellow", ...>

# This is similar to:

MyRecord.create_with(name: 'banana').find_or_initialize_by(id: 2).update(color: 'yellow')


Upsert will perform validation on the object, and return false if it is not valid. To skip validation, pass validate: false:

MyRecord.upsert({id: 1, wisdom: 3}, validate: false)

If you want validations to raise ActiveRecord::RecordInvalid, use upsert!:

MyRecord.upsert!(id: 1, wisdom: 3)

Or using the instance method:

r = 1, name: 'bar')

Gotcha with database defaults

When a table is defined with a database default for a field, this gotcha can occur when trying to explicitly upsert a record to the default value (from a non-default value).

Example: a table called hardwares has a prio column with a default value.

│ Column  │ Type    │ Default │
│ id      │ integer │ ...     |
│ prio    │ integer │ 999     |

And hardwares has a record with a non-default value for prio. Say, the record with id 1 has a prio of 998.

In this situation, upserting like:

hw = { id: 1, prio: 999 } hw[:prio]).upsert

will not mention the prio column in the ON CONFLICT clause, resulting in no update.

However, upserting like so:

Hardware.upsert(prio: hw[:prio]).id

will indeed update the record in the database back to its default value, 999.

Conflict Clauses

It's possible to specify which columns should be used for the conflict clause. These must comprise a unique index in Postgres.

class Vehicle < ActiveRecord::Base
  upsert_keys [:make, :name]

Vehicle.upsert(make: 'Ford', name: 'F-150', doors: 4)
# => #<Vehicle id: 1, make: 'Ford', name: 'Focus', doors: 2>

Vehicle.create(make: 'Ford', name: 'Focus', doors: 4)
# => #<Vehicle id: 2, make: 'Ford', name: 'Focus', doors: 4>

r = 'Ford', name: 'F-150')
r.doors = 2
# => #<Vehicle id: 1, make: 'Ford', name: 'Focus', doors: 2>

Partial indexes can be supported with the addition of a where clause.

class Account < ApplicationRecord
  upsert_keys :name, where: 'active is TRUE'

Custom index can be handled with a Hash containing a literal key :

class Account < ApplicationRecord
  upsert_keys literal: 'md5(my_long_field)'

Overriding the models' upsert_keys when calling #upsert or .upsert:

  Account.upsert(attrs, opts: { upsert_keys: [:foo, :bar] })
  # Or, on an instance:
  .upsert(opts: { upsert_keys: [:foo, :bar] })

Overriding the models' upsert_options (partial index) when calling #upsert or .upsert:

  Account.upsert(attrs, opts: { upsert_options: { where: 'foo IS NOT NULL' } })
  # Or, on an instance:
  .upsert(opts: { upsert_options: { where: 'foo IS NOT NULL' } })

Comparing to native Rails 6 Upsert

Rails 6 (via the "Add insert_many to ActiveRecord models" PR #35077) added the ability to create or update individual records through #insert and #upsert and similarly the ability to create or update multiple records through #insert_all and #upsert_all.

Here is a quick comparison of how the Rails native ActiveRecord::Persistence#upsert feature compares to what's offered in this gem:

Feature active_record_upsert Rails native ActiveRecord::Persistence#upsert
Set model level conflict clause Yes, through #upsert_keys No, but can be passed in through the :unique_by option
Ability to invoke validations and callbacks Yes No
Automatically sets created_at/updated_at timestamps Yes Yes (Rails 7.0+)
Checks for unique index on the database No[^1] Yes
Use associations in upsert calls Yes No
Return object type Instantiated ActiveRecord model ActiveRecord::Result

[^1]: Though the gem does not check for the index first, the upsert will still fail due to the database constraint.


Make sure to have an upsert_test database:

bin/ db:create db:migrate DATABASE_URL=postgresql://localhost/upsert_test

Then run rspec.


Bug reports and pull requests are welcome on GitHub at