Module: ActiveVersion::Database::Triggers::PostgreSQL

Defined in:
lib/active_version/database/triggers/postgresql.rb

Overview

PostgreSQL trigger support for ActiveVersion

Class Method Summary collapse

Class Method Details

.drop_trigger(trigger_name, table_name) ⇒ String

Drop trigger

Parameters:

  • trigger_name (String) —

    Name of the trigger

  • table_name (String) —

    Name of the table

Returns:

  • (String) —

    SQL for DROP TRIGGER statement



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# File 'lib/active_version/database/triggers/postgresql.rb', line 212

def drop_trigger(trigger_name, table_name)
  "DROP TRIGGER IF EXISTS #{trigger_name} ON #{table_name} CASCADE;"
end

.drop_trigger_function(function_name) ⇒ String

Drop trigger function

Parameters:

  • function_name (String) —

    Name of the function

Returns:

  • (String) —

    SQL for DROP FUNCTION statement



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# File 'lib/active_version/database/triggers/postgresql.rb', line 204

def drop_trigger_function(function_name)
  "DROP FUNCTION IF EXISTS #{function_name}() CASCADE;"
end

.generate_audit_trigger(table_name, options = {}) ⇒ String

Generate trigger for audits

Parameters:

  • table_name (String) —

    Name of the table

  • options (Hash) (defaults to: {}) —

    Trigger options

Returns:

  • (String) —

    SQL for CREATE TRIGGER statement



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# File 'lib/active_version/database/triggers/postgresql.rb', line 114

def generate_audit_trigger(table_name, options = {})
  function_name = "active_version_audit_#{table_name}"
  trigger_name = options[:trigger_name] || "active_version_audit_on_#{table_name}"
  events = options[:events] || [:insert, :update, :delete]

  event_clause = events.map(&:upcase).join(" OR ")

  <<~SQL
    CREATE TRIGGER #{trigger_name}
    AFTER #{event_clause} ON #{table_name}
    FOR EACH ROW
    WHEN (coalesce(current_setting('active_version.disabled', true), '') <> 'on')
    EXECUTE FUNCTION #{function_name}();
  SQL
end

.generate_audit_trigger_function(table_name, audit_table_name, options = {}) ⇒ String

Generate trigger function for audits

Parameters:

  • table_name (String) —

    Name of the table to create trigger for

  • audit_table_name (String) —

    Name of the audit table

  • options (Hash) (defaults to: {}) —

    Trigger options

Returns:

  • (String) —

    SQL for trigger function



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# File 'lib/active_version/database/triggers/postgresql.rb', line 12

def generate_audit_trigger_function(table_name, audit_table_name, options = {})
  function_name = "active_version_audit_#{table_name}"
  auditable_type = options[:auditable_type] || table_name.classify
  version_column = options[:version_column] || "version"
  changes_column = options[:changes_column] || "audited_changes"
  context_column = options[:context_column] || "audited_context"
  action_column = options[:action_column] || "action"

  <<~SQL
    CREATE OR REPLACE FUNCTION #{function_name}()
    RETURNS TRIGGER AS $$
    DECLARE
      new_version INTEGER;
      changes JSONB;
      context_data JSONB;
      action_type TEXT;
    BEGIN
      -- Determine action
      IF TG_OP = 'INSERT' THEN
        action_type := 'create';
        changes := to_jsonb(NEW.*);
      ELSIF TG_OP = 'UPDATE' THEN
        action_type := 'update';
        changes := jsonb_build_object(
          'old', to_jsonb(OLD.*),
          'new', to_jsonb(NEW.*)
        );
      ELSIF TG_OP = 'DELETE' THEN
        action_type := 'destroy';
        changes := to_jsonb(OLD.*);
      END IF;

      -- Get version number
      IF action_type = 'create' THEN
        new_version := 1;
      ELSE
        SELECT COALESCE(MAX(#{version_column}), 0) + 1
        INTO new_version
        FROM #{audit_table_name}
        WHERE #{audit_table_name}.auditable_id = COALESCE(NEW.id, OLD.id)
          AND #{audit_table_name}.auditable_type = '#{auditable_type}';
      END IF;

      -- Get context from session variables (if set)
      context_data := COALESCE(
        current_setting('active_version.context', true)::jsonb,
        '{}'::jsonb
      );

      -- Insert audit record
      IF TG_OP = 'DELETE' THEN
        INSERT INTO #{audit_table_name} (
          auditable_id,
          auditable_type,
          #{action_column},
          #{changes_column},
          #{version_column},
          #{context_column},
          created_at,
          updated_at
        ) VALUES (
          OLD.id,
          '#{auditable_type}',
          action_type,
          changes,
          new_version,
          context_data,
          NOW(),
          NOW()
        );
        RETURN OLD;
      ELSE
        INSERT INTO #{audit_table_name} (
          auditable_id,
          auditable_type,
          #{action_column},
          #{changes_column},
          #{version_column},
          #{context_column},
          created_at,
          updated_at
        ) VALUES (
          NEW.id,
          '#{auditable_type}',
          action_type,
          changes,
          new_version,
          context_data,
          NOW(),
          NOW()
        );
        RETURN NEW;
      END IF;
    END;
    $$ LANGUAGE plpgsql;
  SQL
end

.generate_revision_trigger(table_name, options = {}) ⇒ String

Generate trigger for revisions

Parameters:

  • table_name (String) —

    Name of the table

  • options (Hash) (defaults to: {}) —

    Trigger options

Returns:

  • (String) —

    SQL for CREATE TRIGGER statement



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# File 'lib/active_version/database/triggers/postgresql.rb', line 188

def generate_revision_trigger(table_name, options = {})
  function_name = "active_version_revision_#{table_name}"
  trigger_name = options[:trigger_name] || "active_version_revision_on_#{table_name}"

  <<~SQL
    CREATE TRIGGER #{trigger_name}
    BEFORE UPDATE ON #{table_name}
    FOR EACH ROW
    WHEN (coalesce(current_setting('active_version.disabled', true), '') <> 'on')
    EXECUTE FUNCTION #{function_name}();
  SQL
end

.generate_revision_trigger_function(table_name, revision_table_name, options = {}) ⇒ String

Generate trigger function for revisions

Parameters:

  • table_name (String) —

    Name of the table

  • revision_table_name (String) —

    Name of the revision table

  • options (Hash) (defaults to: {}) —

    Trigger options

Returns:

  • (String) —

    SQL for trigger function



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# File 'lib/active_version/database/triggers/postgresql.rb', line 135

def generate_revision_trigger_function(table_name, revision_table_name, options = {})
  function_name = "active_version_revision_#{table_name}"
  foreign_key = options[:foreign_key] || "#{table_name.singularize}_id"
  version_column = options[:version_column] || "version"

  <<~SQL
    CREATE OR REPLACE FUNCTION #{function_name}()
    RETURNS TRIGGER AS $$
    DECLARE
      new_version INTEGER;
      revision_data RECORD;
    BEGIN
      -- Only create revision on UPDATE
      IF TG_OP != 'UPDATE' THEN
        RETURN NEW;
      END IF;

      -- Skip if nothing changed
      IF NEW.* IS NOT DISTINCT FROM OLD.* THEN
        RETURN NEW;
      END IF;

      -- Get next version number
      SELECT COALESCE(MAX(#{version_column}), 0) + 1
      INTO new_version
      FROM #{revision_table_name}
      WHERE #{revision_table_name}.#{foreign_key} = NEW.id;

      -- Create revision with OLD values
      INSERT INTO #{revision_table_name} (
        #{foreign_key},
        #{version_column},
        #{build_revision_columns(table_name, options)},
        created_at,
        updated_at
      )
      SELECT
        NEW.id,
        new_version,
        #{build_revision_values("OLD", table_name, options)},
        NOW(),
        NOW();

      RETURN NEW;
    END;
    $$ LANGUAGE plpgsql;
  SQL
end