Module: SafelyChangeColumnDefault

Extended by:

ActiveSupport::Concern

Included in:

Ci::BuildNeed, Ci::BuildPendingState, Ci::BuildReportResult, Ci::BuildRunnerSession, Ci::BuildTraceChunk, Ci::BuildTraceMetadata, Ci::JobArtifact, Ci::JobVariable, Ci::PendingBuild, Ci::Pipeline, Ci::PipelineVariable, Ci::RunningBuild, Ci::Sources::Pipeline, Ci::Stage, Ci::UnitTestFailure

Defined in:

app/models/concerns/safely_change_column_default.rb

Overview

SafelyChangeColumnDefault concern.

Contains functionality that allows safely changing a column default without downtime. Without this concern, Rails can mutate the old default value to the new default value if the old default is explicitly specified.

Usage:

class SomeModel < ApplicationRecord
  include SafelyChangeColumnDefault

  columns_changing_default :value
end

# Assume a default of 100 for value
SomeModel.create!(value: 100) # INSERT INTO some_model (value) VALUES (100)
change_column_default('some_model', 'value', from: 100, to: 101)
SomeModel.create!(value: 100) # INSERT INTO some_model (value) VALUES (100)
# Without this concern, would be INSERT INTO some_model (value) DEFAULT VALUES and would insert 101.