Strong Schema

🛡️ Brings Strong Migrations safety checks to schema-based database management.

Tools using ActiveRecord::Schema for declarative database management lack safety checks for dangerous operations. This can lead to production issues—such as removing columns without proper safeguards or adding indexes that lock tables.

Strong Schema brings the same proven safety checks from Strong Migrations to schema-based workflows, catching unsafe operations before they reach your database.

Add this line to your application's Gemfile:

gem 'strong_schema'

And then execute:

bundle install

To customize settings, create a configuration file:

# config/strong_schema.rb
require "strong_schema"

StrongMigrations.start_after = 20260214142757
StrongMigrations.lock_timeout = 10.seconds
StrongMigrations.statement_timeout = 1.hour
StrongMigrations.auto_analyze = true

When using Ridgepole, load the configuration file using the -r option:

$ ridgepole --apply -c config/database.yml -r ./config/strong_schema.rb

When you need to bypass safety checks for operations you've verified as safe, use StrongSchema.add_ignore:

# config/strong_schema.rb
require "strong_schema"

# Ignore a specific column removal
StrongSchema.add_ignore do |method, args|
  method == :remove_column && 
    args[0].to_s == "users" && 
    args[1].to_s == "old_email"
end

# Ignore by table name (all operations on the table)
StrongSchema.add_ignore do |method, args|
  args[0].to_s == "legacy_table"
end

The block receives:

• method: Operation symbol (:add_column, :remove_column, :change_column, etc.)
• args: Arguments array. First element is typically the table name.

Note: Operations inside change_table blocks are detected with their original method names (:remove_column, :add_column, etc.), not as :change_table. The same ignore rules work for both direct operations and operations within change_table blocks.

This gem stands on the shoulders of giants. Special thanks to the following project:

• Strong Migrations - Safety checks for migrations

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt.

Bug reports and pull requests are welcome on GitHub at https://github.com/shoma07/strong_schema.

The gem is available as open source under the terms of the MIT License.