Add materialized view support helpers. Fixes #842 (#1004)

db/migrations/20240210233828_create_materialized_view_names.cr

@@ -0,0 +1,22 @@
+class CreateMaterializedViewNames::V20240210233828 < Avram::Migrator::Migration::V1
+  def migrate
+    execute <<-SQL
+    CREATE MATERIALIZED VIEW IF NOT EXISTS all_the_names AS
+      SELECT name FROM admins
+      UNION ALL
+      SELECT name FROM businesses
+      UNION ALL
+      SELECT name FROM customers
+      UNION ALL
+      SELECT name FROM employees
+      UNION ALL
+      SELECT name FROM users
+    SQL
+  end
+
+  def rollback
+    execute <<-SQL
+    DROP MATERIALIZED VIEW IF EXISTS all_the_names
+    SQL
+  end
+end

spec/avram/view_spec.cr

@@ -25,4 +25,16 @@ describe "views" do
     AdminUser.ensure_correct_column_mappings!
     NicknameInfo.ensure_correct_column_mappings!
   end
+
+  describe "materialized views" do
+    it "works" do
+      UserFactory.create(&.name("Yoozur"))
+      AdminFactory.create(&.name("Aadmyn"))
+      emp = EmployeeFactory.create(&.name("Hemploie"))
+      CustomerFactory.create(&.name("Kustoomur").employee_id(emp.id))
+      Name::BaseQuery.new.select_count.should eq(0)
+      Name::BaseQuery.refresh_view
+      Name::BaseQuery.new.select_count.should eq(4)
+    end
+  end
 end

spec/support/models/name.cr

@@ -0,0 +1,5 @@
+class Name < BaseModel
+  view :all_the_names, materialized: true do
+    column name : String
+  end
+end

src/avram/base_query_template.cr

@@ -14,6 +14,12 @@ class Avram::BaseQueryTemplate
         end
       end
 
+      {% if named_args[:materialized_view] %}
+      def self.refresh_view(*, concurrent : Bool = false)
+        {{ type }}.database.exec("REFRESH MATERIALIZED VIEW #{concurrent ? "CONCURRENTLY" : ""} #{{{ type }}.table_name}")
+      end
+      {% end %}
+
       def update(
           {% for column in columns %}
             {{ column[:name] }} : {{ column[:type] }} | Avram::Nothing{% if column[:nilable] %} | Nil{% end %} = Avram::Nothing.new,

src/avram/model.cr

@@ -71,7 +71,7 @@ abstract class Avram::Model
     setup(Avram::SchemaEnforcer.setup)
   end
 
-  macro view(view_name = nil)
+  macro view(view_name = nil, materialized = false)
     {{ yield }}
 
     validate_columns("view")
@@ -85,7 +85,7 @@ abstract class Avram::Model
     setup(Avram::Model.setup_column_info_methods)
     setup(Avram::Model.setup_association_queries)
     setup(Avram::Model.setup_view_schema_enforcer_validations)
-    setup(Avram::BaseQueryTemplate.setup)
+    setup(Avram::BaseQueryTemplate.setup, materialized_view: {{ materialized }})
     setup(Avram::SchemaEnforcer.setup)
   end
 
@@ -141,11 +141,12 @@ abstract class Avram::Model
     column updated_at : Time, autogenerated: true
   end
 
-  macro setup(step)
+  macro setup(step, *args, **named_args)
     {{ step.id }}(
       type: {{ @type }},
       columns: {{ COLUMNS }},
-      associations: {{ ASSOCIATIONS }}
+      associations: {{ ASSOCIATIONS }},
+      {{ named_args.double_splat }}
     )
   end