Add flag --replace_view to migration generator (#368)

README.md

@@ -92,30 +92,18 @@ a new version of it.
 This is not desirable when you have complicated hierarchies of views, especially
 when some of those views may be materialized and take a long time to recreate.
 
-You can use `replace_view` to generate a CREATE OR REPLACE VIEW SQL statement.
-
-See Postgres documentation on how this works:
-http://www.postgresql.org/docs/current/static/sql-createview.html
-
-To start replacing a view run the generator like for a regular change:
+You can use `replace_view` to generate a CREATE OR REPLACE VIEW SQL statement instead by adding the `--replace_view` option to the generate command:
 
 ```sh
-$ rails generate scenic:view search_results
+$ rails generate scenic:view search_results --replace_view
  create db/views/search_results_v02.sql
  create db/migrate/[TIMESTAMP]_update_search_results_to_version_2.rb
 ```
 
-Now, edit the migration. It should look something like:
-
-```ruby
-class UpdateSearchResultsToVersion2 < ActiveRecord::Migration
- def change
- update_view :search_results, version: 2, revert_to_version: 1
- end
-end
-```
+See Postgres documentation on how this works:
+http://www.postgresql.org/docs/current/static/sql-createview.html
 
-Update it to use replace view:
+The migration will look something like this:
 
 ```ruby
 class UpdateSearchResultsToVersion2 < ActiveRecord::Migration
@@ -125,7 +113,7 @@ class UpdateSearchResultsToVersion2 < ActiveRecord::Migration
 end
 ```
 
-Now you can run the migration like normal.
+You can run the migration and the view will be replaced instead.
 
 ## Can I use this view to back a model?
 

lib/generators/scenic/materializable.rb

@@ -15,6 +15,11 @@ module Materializable
  required: false,
  desc: "Adds WITH NO DATA when materialized view creates/updates",
  default: false
+ class_option :replace_view,
+ type: :boolean,
+ required: false,
+ desc: "Uses replace_view instead of update_view",
+ default: false
  end
 
  private
@@ -23,6 +28,10 @@ def materialized?
  options[:materialized]
  end
 
+ def replace_view?
+ options[:replace_view]
+ end
+
  def no_data?
  options[:no_data]
  end

lib/generators/scenic/view/templates/db/migrate/update_view.erb

@@ -1,12 +1,13 @@
 class <%= migration_class_name %> < <%= activerecord_migration_class %>
  def change
+ <% method_name = replace_view? ? 'replace_view' : 'update_view' %>
  <%- if materialized? -%>
- update_view <%= formatted_plural_name %>,
+ <%= method_name %> <%= formatted_plural_name %>,
  version: <%= version %>,
  revert_to_version: <%= previous_version %>,
  materialized: <%= no_data? ? "{ no_data: true }" : true %>
  <%- else -%>
- update_view <%= formatted_plural_name %>, version: <%= version %>, revert_to_version: <%= previous_version %>
+ <%= method_name %> <%= formatted_plural_name %>, version: <%= version %>, revert_to_version: <%= previous_version %>
  <%- end -%>
  end
 end

spec/generators/scenic/view/view_generator_spec.rb

@@ -37,6 +37,18 @@
  end
  end
 
+ it "uses 'replace_view' instead of 'update_view' if replace flag is set" do
+ with_view_definition("aired_episodes", 1, "hello") do
+ allow(Dir).to receive(:entries).and_return(["aired_episodes_v01.sql"])
+
+ run_generator ["aired_episode", "--replace_view"]
+ migration = migration_file(
+ "db/migrate/update_aired_episodes_to_version_2.rb",
+ )
+ expect(migration).to contain "replace_view"
+ end
+ end
+
  context "for views created in a schema other than 'public'" do
  it "creates a view definition" do
  view_definition = file("db/views/non_public_searches_v01.sql")