adapter.rb in chrono_model-0.3.1

- old
+ new

@@ -6,13 +6,18 @@
   # This class implements all ActiveRecord::ConnectionAdapters::SchemaStatements
   # methods adding support for temporal extensions. It inherits from the Postgres
   # adapter for a clean override of its methods using super.
   #
   class Adapter < ActiveRecord::ConnectionAdapters::PostgreSQLAdapter
-    TEMPORAL_SCHEMA = 'temporal' # The schema holding current data
-    HISTORY_SCHEMA  = 'history'  # The schema holding historical data
+    # The schema holding current data
+    TEMPORAL_SCHEMA = 'temporal'
 
+    # The schema holding historical data
+    HISTORY_SCHEMA  = 'history'
+
+    # Chronomodel is supported starting with PostgreSQL >= 9.0
+    #
     def chrono_supported?
       postgresql_version >= 90000
     end
 
     # Creates the given table, possibly creating the temporal schema
@@ -85,10 +90,28 @@
             execute "ALTER TABLE #{table_name} SET SCHEMA #{TEMPORAL_SCHEMA}"
             _on_history_schema { chrono_create_history_for(table_name) }
             chrono_create_view_for(table_name)
 
             TableCache.add! table_name
+
+            # Optionally copy the plain table data, setting up history
+            # retroactively.
+            #
+            if options[:copy_data]
+              seq  = _on_history_schema { serial_sequence(table_name, primary_key(table_name)) }
+              from = options[:validity] || '0001-01-01 00:00:00'
+
+              execute %[
+                INSERT INTO #{HISTORY_SCHEMA}.#{table_name}
+                SELECT *,
+                  nextval('#{seq}')               AS hid,
+                  timestamp '#{from}'             AS valid_from,
+                  timestamp '9999-12-31 00:00:00' AS valid_to,
+                  timezone('UTC', now())          AS recorded_at
+                FROM #{TEMPORAL_SCHEMA}.#{table_name}
+              ]
+            end
           end
 
           chrono_alter(table_name) { super table_name, options, &block }
         else
           if options[:temporal] == false && is_chrono?(table_name)
@@ -351,19 +374,35 @@
 
         fields, values = columns.join(', '), columns.map {|c| "new.#{c}"}.join(', ')
 
         # INSERT - inert data both in the temporal table and in the history one.
         #
-        execute <<-SQL
-          CREATE OR REPLACE RULE #{table}_ins AS ON INSERT TO #{table} DO INSTEAD (
+        if sequence.present?
+          execute <<-SQL
+            CREATE OR REPLACE RULE #{table}_ins AS ON INSERT TO #{table} DO INSTEAD (
 
-            INSERT INTO #{current} ( #{fields} ) VALUES ( #{values} );
+              INSERT INTO #{current} ( #{fields} ) VALUES ( #{values} );
 
-            INSERT INTO #{history} ( #{pk}, #{fields}, valid_from )
-            VALUES ( currval('#{sequence}'), #{values}, timezone('UTC', now()) )
-            RETURNING #{pk}, #{fields}
-          )
-        SQL
+              INSERT INTO #{history} ( #{pk}, #{fields}, valid_from )
+              VALUES ( currval('#{sequence}'), #{values}, timezone('UTC', now()) )
+              RETURNING #{pk}, #{fields}
+            )
+          SQL
+        else
+          fields_with_pk = "#{pk}, " << fields
+          values_with_pk = "new.#{pk}, " << values
+
+          execute <<-SQL
+            CREATE OR REPLACE RULE #{table}_ins AS ON INSERT TO #{table} DO INSTEAD (
+
+              INSERT INTO #{current} ( #{fields_with_pk} ) VALUES ( #{values_with_pk} );
+
+              INSERT INTO #{history} ( #{fields_with_pk}, valid_from )
+              VALUES ( #{values_with_pk}, timezone('UTC', now()) )
+              RETURNING #{fields_with_pk}
+            )
+          SQL
+        end
 
         # UPDATE - set the last history entry validity to now, save the current data
         # in a new history entry and update the temporal table with the new data.
         #
         execute <<-SQL