moved sql related code to its own engine area

Conflicts:

	lib/arel/engine.rb
	lib/arel/extensions/object.rb
	lib/arel/predicates.rb
	lib/arel/primitives/attribute.rb
	lib/arel/primitives/expression.rb
	lib/arel/primitives/value.rb
	lib/arel/relations/operations/join.rb
	lib/arel/relations/relation.rb
	lib/arel/relations/utilities/externalization.rb
	lib/arel/relations/utilities/nil.rb
	lib/arel/relations/writes/delete.rb
	lib/arel/relations/writes/insert.rb
	lib/arel/relations/writes/update.rb
	spec/arel/unit/relations/skip_spec.rb
	spec/arel/unit/relations/take_spec.rb
	spec/spec_helper.rb

13 files changed, 167 insertions, 0 deletions

diff --git a/lib/arel/engines/sql/relations/operations.rb b/lib/arel/engines/sql/relations/operations.rb
new file mode 100644
index 0000000000..ff33fc6bc3
--- /dev/null
+++ b/lib/arel/engines/sql/relations/operations.rb
@@ -0,0 +1,2 @@
+require 'arel/engines/sql/relations/operations/alias'
+require 'arel/engines/sql/relations/operations/join'
diff --git a/lib/arel/engines/sql/relations/operations/alias.rb b/lib/arel/engines/sql/relations/operations/alias.rb
new file mode 100644
index 0000000000..32c9911a69
--- /dev/null
+++ b/lib/arel/engines/sql/relations/operations/alias.rb
@@ -0,0 +1,5 @@
+module Arel
+  class Alias < Compound
+    include Recursion::BaseCase
+  end
+end
\ No newline at end of file
diff --git a/lib/arel/engines/sql/relations/operations/join.rb b/lib/arel/engines/sql/relations/operations/join.rb
new file mode 100644
index 0000000000..be21119bc9
--- /dev/null
+++ b/lib/arel/engines/sql/relations/operations/join.rb
@@ -0,0 +1,19 @@
+module Arel
+  class Join < Relation
+    def table_sql(formatter = Sql::TableReference.new(self))
+      relation1.externalize.table_sql(formatter)
+    end
+
+    def joins(environment, formatter = Sql::TableReference.new(environment))
+      @joins ||= begin
+        this_join = [
+          join_sql,
+          relation2.externalize.table_sql(formatter),
+          ("ON" unless predicates.blank?),
+          (ons + relation2.externalize.wheres).collect { |p| p.bind(environment).to_sql(Sql::WhereClause.new(environment)) }.join(' AND ')
+        ].compact.join(" ")
+        [relation1.joins(environment), this_join, relation2.joins(environment)].compact.join(" ")
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/arel/engines/sql/relations/relation.rb b/lib/arel/engines/sql/relations/relation.rb
new file mode 100644
index 0000000000..5fd4121176
--- /dev/null
+++ b/lib/arel/engines/sql/relations/relation.rb
@@ -0,0 +1,28 @@
+module Arel
+  class Relation
+    def to_sql(formatter = Sql::SelectStatement.new(self))
+      formatter.select select_sql, self
+    end
+
+    def select_sql
+      [
+        "SELECT     #{attributes.collect { |a| a.to_sql(Sql::SelectClause.new(self)) }.join(', ')}",
+        "FROM       #{table_sql(Sql::TableReference.new(self))}",
+        (joins(self)                                                                                    unless joins(self).blank? ),
+        ("WHERE     #{wheres   .collect { |w| w.to_sql(Sql::WhereClause.new(self)) }.join("\n\tAND ")}" unless wheres.blank?      ),
+        ("GROUP BY  #{groupings.collect { |g| g.to_sql(Sql::GroupClause.new(self)) }.join(', ')}"       unless groupings.blank?   ),
+        ("ORDER BY  #{orders   .collect { |o| o.to_sql(Sql::OrderClause.new(self)) }.join(', ')}"       unless orders.blank?      ),
+        ("LIMIT     #{taken}"                                                                           unless taken.blank?       ),
+        ("OFFSET    #{skipped}"                                                                         unless skipped.blank?     )
+      ].compact.join("\n")
+    end
+
+    def inclusion_predicate_sql
+      "IN"
+    end
+
+    def christener
+      @christener ||= Sql::Christener.new
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/arel/engines/sql/relations/table.rb b/lib/arel/engines/sql/relations/table.rb
new file mode 100644
index 0000000000..0433abbbb2
--- /dev/null
+++ b/lib/arel/engines/sql/relations/table.rb
@@ -0,0 +1,36 @@
+module Arel
+  class Table < Relation
+    include Recursion::BaseCase
+
+    cattr_accessor :engine
+    attr_reader :name, :engine
+    hash_on :name
+
+    def initialize(name, engine = Table.engine)
+      @name, @engine = name.to_s, engine
+    end
+
+    def attributes
+      @attributes ||= columns.collect do |column|
+        Attribute.new(self, column.name.to_sym)
+      end
+    end
+
+    def column_for(attribute)
+      has_attribute?(attribute) and columns.detect { |c| c.name == attribute.name.to_s }
+    end
+
+    def columns
+      @columns ||= engine.columns(name, "#{name} Columns")
+    end
+
+    def reset
+      @attributes = @columns = nil
+    end
+
+    def ==(other)
+      Table      === other and
+      name       ==  other.name
+    end
+  end
+end
diff --git a/lib/arel/engines/sql/relations/utilities.rb b/lib/arel/engines/sql/relations/utilities.rb
new file mode 100644
index 0000000000..a1451ed448
--- /dev/null
+++ b/lib/arel/engines/sql/relations/utilities.rb
@@ -0,0 +1,3 @@
+require 'arel/engines/sql/relations/utilities/recursion'
+require 'arel/engines/sql/relations/utilities/externalization'
+require 'arel/engines/sql/relations/utilities/nil'
diff --git a/lib/arel/engines/sql/relations/utilities/externalization.rb b/lib/arel/engines/sql/relations/utilities/externalization.rb
new file mode 100644
index 0000000000..1ac6f2de8e
--- /dev/null
+++ b/lib/arel/engines/sql/relations/utilities/externalization.rb
@@ -0,0 +1,14 @@
+module Arel
+  class Externalization < Compound
+    include Recursion::BaseCase
+
+    def table_sql(formatter = Sql::TableReference.new(relation))
+      formatter.select relation.select_sql, self
+    end
+
+    # REMOVEME
+    def name
+      relation.name + '_external'
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/arel/engines/sql/relations/utilities/nil.rb b/lib/arel/engines/sql/relations/utilities/nil.rb
new file mode 100644
index 0000000000..77534b25ad
--- /dev/null
+++ b/lib/arel/engines/sql/relations/utilities/nil.rb
@@ -0,0 +1,6 @@
+module Arel
+  class Nil < Relation
+    def table_sql(formatter = nil); '' end
+    def name; '' end
+  end
+end
\ No newline at end of file
diff --git a/lib/arel/engines/sql/relations/utilities/recursion.rb b/lib/arel/engines/sql/relations/utilities/recursion.rb
new file mode 100644
index 0000000000..848b059507
--- /dev/null
+++ b/lib/arel/engines/sql/relations/utilities/recursion.rb
@@ -0,0 +1,13 @@
+module Arel
+  module Recursion
+    module BaseCase
+      def table
+        self
+      end
+
+      def table_sql(formatter = Sql::TableReference.new(self))
+        formatter.table self
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/arel/engines/sql/relations/writes.rb b/lib/arel/engines/sql/relations/writes.rb
new file mode 100644
index 0000000000..dcadc326d9
--- /dev/null
+++ b/lib/arel/engines/sql/relations/writes.rb
@@ -0,0 +1,3 @@
+require 'arel/engines/sql/relations/writes/delete'
+require 'arel/engines/sql/relations/writes/insert'
+require 'arel/engines/sql/relations/writes/update'
diff --git a/lib/arel/engines/sql/relations/writes/delete.rb b/lib/arel/engines/sql/relations/writes/delete.rb
new file mode 100644
index 0000000000..b22ee51e24
--- /dev/null
+++ b/lib/arel/engines/sql/relations/writes/delete.rb
@@ -0,0 +1,12 @@
+module Arel
+  class Deletion < Compound
+    def to_sql(formatter = nil)
+      [
+        "DELETE",
+        "FROM #{table_sql}",
+        ("WHERE #{wheres.collect(&:to_sql).join('\n\tAND ')}" unless wheres.blank?  ),
+        ("LIMIT #{taken}"                                     unless taken.blank?    ),
+      ].compact.join("\n")
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/arel/engines/sql/relations/writes/insert.rb b/lib/arel/engines/sql/relations/writes/insert.rb
new file mode 100644
index 0000000000..aac9c87a5b
--- /dev/null
+++ b/lib/arel/engines/sql/relations/writes/insert.rb
@@ -0,0 +1,12 @@
+module Arel
+  class Insert < Compound
+    def to_sql(formatter = nil)
+      [
+        "INSERT",
+        "INTO #{table_sql}",
+        "(#{record.keys.collect { |key| engine.quote_column_name(key.name) }.join(', ')})",
+        "VALUES (#{record.collect { |key, value| key.format(value) }.join(', ')})"
+      ].join("\n")
+    end
+  end
+end
\ No newline at end of file
diff --git a/lib/arel/engines/sql/relations/writes/update.rb b/lib/arel/engines/sql/relations/writes/update.rb
new file mode 100644
index 0000000000..3e35a0d5cc
--- /dev/null
+++ b/lib/arel/engines/sql/relations/writes/update.rb
@@ -0,0 +1,14 @@
+module Arel
+  class Update < Compound
+    def to_sql(formatter = nil)
+      [
+        "UPDATE #{table_sql} SET",
+        assignments.collect do |attribute, value|
+          "#{engine.quote_column_name(attribute.name)} = #{attribute.format(value)}"
+        end.join(",\n"),
+        ("WHERE #{wheres.collect(&:to_sql).join('\n\tAND ')}"  unless wheres.blank?  ),
+        ("LIMIT #{taken}"                                      unless taken.blank?    )
+      ].join("\n")
+    end
+  end
+end
\ No newline at end of file