ridgepole-view

Ridgepole plugin that adds database view management using Scenic.

Ridgepole manages database schema declaratively via a Schemafile, but does not support database views. This plugin bridges Ridgepole and Scenic, enabling you to define views in your Schemafile and manage them with the same ridgepole --apply workflow.

Add to your Gemfile:

gem "ridgepole-view", require: "ridgepole-view"

Or use Ridgepole's -r flag:

ridgepole -r ridgepole-view -a -c config.yml -f Schemafile

• Ruby >= 2.7
• Ridgepole >= 1.0
• Scenic >= 1.5
• PostgreSQL

create_table "users", force: :cascade do |t|
  t.column "name", :string
  t.column "email", :string
  t.column "active", :boolean, default: true
end

create_view "active_users", sql_definition: <<-SQL
  SELECT users.name, users.email
  FROM users
  WHERE users.active = true
SQL

create_view "user_stats", materialized: true, sql_definition: <<-SQL
  SELECT count(*) AS total_users,
         count(*) FILTER (WHERE active) AS active_users
  FROM users
SQL

# Apply schema (including views)
ridgepole -r ridgepole-view -a -c config.yml -f Schemafile

# Dry run
ridgepole -r ridgepole-view -a --dry-run -c config.yml -f Schemafile

# Export current schema (including views)
ridgepole -r ridgepole-view -e -c config.yml -o Schemafile

Ridgepole applies schema changes through the following pipeline:

Schemafile (DSL)
    │
    ▼
DSLParser::Context  ─── Evaluates the Schemafile via instance_eval, converting
    │                    DSL methods (create_table, etc.) into a definition hash
    ▼
DSLParser           ─── Validates the definition hash (checks for orphan
    │                    indexes, foreign keys without tables, etc.)
    ▼
Dumper              ─── Reads the current DB state as a DSL string via
    │                    ActiveRecord::SchemaDumper (also used for export)
    ▼
Diff                ─── Compares the "current state" (from Dumper) with the
    │                    "desired state" (from DSLParser) and detects differences
    ▼
Delta               ─── Generates migration scripts (create_table, drop_table,
                         etc.) from the diff result and executes them

This plugin injects view support into each component above via prepend:

View changes are applied through Scenic's Statements module (create_view, drop_view), which delegates to Scenic.database (PostgreSQL adapter).

Ridgepole's Diff#diff and DSLParser#check_definition iterate over all keys in the definition hash, treating each key as a table name and accessing table-specific attributes such as :definition and :options. Since the view data structure ({ sql_definition:, materialized: }) differs from the table structure, passing it through as-is would cause NoMethodError or false validation failures.

To avoid this, the plugin temporarily extracts the :views key before calling super, allowing Ridgepole's core table processing to run without interference. After super completes, the :views key is restored. View diffing is handled by a separate diff_views method.

• Added view: create_view is generated
• Removed view: drop_view is generated
• Changed view (SQL or materialized flag): drop_view (old) then create_view (new)
• Unchanged view: No action
• SQL comparison normalizes whitespace and case

bundle install
bundle exec rspec

• Views referencing other views are not topologically sorted. Define them in dependency order in the Schemafile.
• SQL normalization downcases the entire definition, including string literals.
• --merge mode (add-only) does not prevent view deletion. Views follow the same diff logic regardless.

MIT