Merge branch 'schema'

* schema:
  add uuid primary key support
  separate primary key from column type
  push the mysql add_column up to the abstract adapter
  allow multiple add columns
  pull add_column_options! off the pg connection class
  add a pg visitor for dealing with schema modification
  push alter table add column sql in to the schema modification visitor
  there is no reason to check for an already defined column
  push column initialization down to the factory method
  @columns list is no longer necessary
  keep ivars private, do not manipulate them outside their owner object
  factory methods should not alter object state
  push SQL generation inside the schema creation object
  mostly decouple TableDefinition from the database connection
  remove to_sql from TableDefinition
  decouple column definition from the database connection
  stop depending on sql_type in pg
  remove knowledge of SQL from the column definition object

1 files changed, 69 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index 7949bcb5ce..0ebe46be55 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -100,6 +100,75 @@ module ActiveRecord
         @visitor             = nil
       end
 
+      class SchemaCreation
+        def initialize(conn)
+          @conn  = conn
+          @cache = {}
+        end
+
+        def accept(o)
+          m = @cache[o.class] ||= "visit_#{o.class.name.split('::').last}"
+          send m, o
+        end
+
+        private
+
+        def visit_AlterTable(o)
+          sql = "ALTER TABLE #{quote_table_name(o.name)} "
+          sql << o.adds.map { |col| visit_AddColumn col }.join(' ')
+        end
+
+        def visit_AddColumn(o)
+          sql_type = type_to_sql(o.type.to_sym, o.limit, o.precision, o.scale)
+          sql = "ADD #{quote_column_name(o.name)} #{sql_type}"
+          add_column_options!(sql, column_options(o))
+        end
+
+        def visit_ColumnDefinition(o)
+          sql_type = type_to_sql(o.type.to_sym, o.limit, o.precision, o.scale)
+          column_sql = "#{quote_column_name(o.name)} #{sql_type}"
+          add_column_options!(column_sql, column_options(o)) unless o.primary_key?
+          column_sql
+        end
+
+        def visit_TableDefinition(o)
+          create_sql = "CREATE#{' TEMPORARY' if o.temporary} TABLE "
+          create_sql << "#{quote_table_name(o.name)} ("
+          create_sql << o.columns.map { |c| accept c }.join(', ')
+          create_sql << ") #{o.options}"
+          create_sql
+        end
+
+        def column_options(o)
+          column_options = {}
+          column_options[:null] = o.null unless o.null.nil?
+          column_options[:default] = o.default unless o.default.nil?
+          column_options[:column] = o
+          column_options
+        end
+
+        def quote_column_name(name)
+          @conn.quote_column_name name
+        end
+
+        def quote_table_name(name)
+          @conn.quote_table_name name
+        end
+
+        def type_to_sql(type, limit, precision, scale)
+          @conn.type_to_sql type.to_sym, limit, precision, scale
+        end
+
+        def add_column_options!(column_sql, column_options)
+          @conn.add_column_options! column_sql, column_options
+          column_sql
+        end
+      end
+
+      def schema_creation
+        SchemaCreation.new self
+      end
+
       def lease
         synchronize do
           unless in_use