From 6e9cf0cb4390f1d210edbecc660290aaea6b4d72 Mon Sep 17 00:00:00 2001
From: Emilio Tagua <miloops@gmail.com>
Date: Mon, 15 Feb 2010 17:20:24 -0300
Subject: Extract SQL logic from Arel::Relation into compilers.
---
lib/arel/engines/sql/compilers/mysql_compiler.rb | 7 ++
.../engines/sql/compilers/postgresql_compiler.rb | 33 +++++++++
lib/arel/engines/sql/compilers/sqlite_compiler.rb | 9 +++
lib/arel/engines/sql/engine.rb | 3 +-
lib/arel/engines/sql/relations.rb | 1 +
lib/arel/engines/sql/relations/compiler.rb | 63 +++++++++++++++++
lib/arel/engines/sql/relations/relation.rb | 78 ++--------------------
lib/arel/engines/sql/relations/table.rb | 8 +++
.../sql/relations/utilities/externalization.rb | 2 +-
9 files changed, 130 insertions(+), 74 deletions(-)
create mode 100644 lib/arel/engines/sql/compilers/mysql_compiler.rb
create mode 100644 lib/arel/engines/sql/compilers/postgresql_compiler.rb
create mode 100644 lib/arel/engines/sql/compilers/sqlite_compiler.rb
create mode 100644 lib/arel/engines/sql/relations/compiler.rb
(limited to 'lib/arel/engines')
diff --git a/lib/arel/engines/sql/compilers/mysql_compiler.rb b/lib/arel/engines/sql/compilers/mysql_compiler.rb
new file mode 100644
index 0000000000..e3cf1f2add
--- /dev/null
+++ b/lib/arel/engines/sql/compilers/mysql_compiler.rb
@@ -0,0 +1,7 @@
+module Arel
+ module SqlCompiler
+ class MySQLCompiler < GenericCompiler
+ end
+ end
+end
+
diff --git a/lib/arel/engines/sql/compilers/postgresql_compiler.rb b/lib/arel/engines/sql/compilers/postgresql_compiler.rb
new file mode 100644
index 0000000000..c3360b53a5
--- /dev/null
+++ b/lib/arel/engines/sql/compilers/postgresql_compiler.rb
@@ -0,0 +1,33 @@
+module Arel
+ module SqlCompiler
+ class PostgreSQLCompiler < GenericCompiler
+
+ def select_sql
+ if !orders.blank? && using_distinct_on?
+ # PostgreSQL does not allow arbitrary ordering when using DISTINCT ON, so we work around this
+ # by wrapping the +sql+ string as a sub-select and ordering in that query.
+ order = order_clauses.join(', ').split(',').map { |s| s.strip }.reject(&:blank?)
+ order = order.zip((0...order.size).to_a).map { |s,i| "id_list.alias_#{i} #{'DESC' if s =~ /\bdesc$/i}" }.join(', ')
+
+ query = build_query \
+ "SELECT #{select_clauses.kind_of?(::Array) ? select_clauses.join("") : select_clauses.to_s}",
+ "FROM #{from_clauses}",
+ (joins(self) unless joins(self).blank? ),
+ ("WHERE #{where_clauses.join(" AND ")}" unless wheres.blank? ),
+ ("GROUP BY #{group_clauses.join(', ')}" unless groupings.blank? ),
+ ("HAVING #{having_clauses.join(', ')}" unless havings.blank? ),
+ ("#{locked}" unless locked.blank? )
+
+ build_query \
+ "SELECT * FROM (#{query}) AS id_list",
+ "ORDER BY #{order}",
+ ("LIMIT #{taken}" unless taken.blank? ),
+ ("OFFSET #{skipped}" unless skipped.blank? )
+
+ else
+ super
+ end
+ end
+ end
+ end
+end
diff --git a/lib/arel/engines/sql/compilers/sqlite_compiler.rb b/lib/arel/engines/sql/compilers/sqlite_compiler.rb
new file mode 100644
index 0000000000..c2f78cd235
--- /dev/null
+++ b/lib/arel/engines/sql/compilers/sqlite_compiler.rb
@@ -0,0 +1,9 @@
+module Arel
+ module SqlCompiler
+ class SQLiteCompiler < GenericCompiler
+ def locked
+ nil
+ end
+ end
+ end
+end
diff --git a/lib/arel/engines/sql/engine.rb b/lib/arel/engines/sql/engine.rb
index eb9dd85602..5bb8463699 100644
--- a/lib/arel/engines/sql/engine.rb
+++ b/lib/arel/engines/sql/engine.rb
@@ -1,12 +1,13 @@
module Arel
module Sql
class Engine
+
def initialize(ar = nil)
@ar = ar
end
def connection
- @ar.connection
+ @ar ? @ar.connection : nil
end
def adapter_name
diff --git a/lib/arel/engines/sql/relations.rb b/lib/arel/engines/sql/relations.rb
index 8360a1f806..afe6ac775f 100644
--- a/lib/arel/engines/sql/relations.rb
+++ b/lib/arel/engines/sql/relations.rb
@@ -2,6 +2,7 @@ require 'arel/engines/sql/relations/utilities/compound'
require 'arel/engines/sql/relations/utilities/recursion'
require 'arel/engines/sql/relations/utilities/externalization'
require 'arel/engines/sql/relations/utilities/nil'
+require 'arel/engines/sql/relations/compiler'
require 'arel/engines/sql/relations/relation'
require 'arel/engines/sql/relations/table'
require 'arel/engines/sql/relations/operations/join'
diff --git a/lib/arel/engines/sql/relations/compiler.rb b/lib/arel/engines/sql/relations/compiler.rb
new file mode 100644
index 0000000000..6026fc126f
--- /dev/null
+++ b/lib/arel/engines/sql/relations/compiler.rb
@@ -0,0 +1,63 @@
+module Arel
+ module SqlCompiler
+ class GenericCompiler
+ attr_reader :relation
+
+ def initialize(relation)
+ @relation = relation
+ end
+
+ def select_sql
+ build_query \
+ "SELECT #{select_clauses.join(', ')}",
+ "FROM #{from_clauses}",
+ (joins(self) unless joins(self).blank? ),
+ ("WHERE #{where_clauses.join(" AND ")}" unless wheres.blank? ),
+ ("GROUP BY #{group_clauses.join(', ')}" unless groupings.blank? ),
+ ("HAVING #{having_clauses.join(', ')}" unless havings.blank? ),
+ ("ORDER BY #{order_clauses.join(', ')}" unless orders.blank? ),
+ ("LIMIT #{taken}" unless taken.blank? ),
+ ("OFFSET #{skipped}" unless skipped.blank? ),
+ ("#{locked}" unless locked.blank?)
+ end
+
+ protected
+ def method_missing(method, *args, &block)
+ relation.send(method, *args, &block)
+ end
+
+ def build_query(*parts)
+ parts.compact.join(" ")
+ end
+
+ def from_clauses
+ sources.blank? ? table_sql(Sql::TableReference.new(relation)) : sources
+ end
+
+ def select_clauses
+ attributes.collect { |a| a.to_sql(Sql::SelectClause.new(relation)) }
+ end
+
+ def where_clauses
+ wheres.collect { |w| w.to_sql(Sql::WhereClause.new(relation)) }
+ end
+
+ def group_clauses
+ groupings.collect { |g| g.to_sql(Sql::GroupClause.new(relation)) }
+ end
+
+ def having_clauses
+ havings.collect { |g| g.to_sql(Sql::HavingClause.new(relation)) }
+ end
+
+ def order_clauses
+ orders.collect { |o| o.to_sql(Sql::OrderClause.new(relation)) }
+ end
+
+ def using_distinct_on?
+ select_clauses.any? { |x| x =~ /DISTINCT ON/ }
+ end
+ end
+
+ end
+end
diff --git a/lib/arel/engines/sql/relations/relation.rb b/lib/arel/engines/sql/relations/relation.rb
index 78508595fd..15903412d5 100644
--- a/lib/arel/engines/sql/relations/relation.rb
+++ b/lib/arel/engines/sql/relations/relation.rb
@@ -1,86 +1,20 @@
module Arel
class Relation
- def to_sql(formatter = Sql::SelectStatement.new(self))
- formatter.select select_sql, self
- end
-
- def select_sql
- if engine.adapter_name == "PostgreSQL" && !orders.blank? && using_distinct_on?
- # PostgreSQL does not allow arbitrary ordering when using DISTINCT ON, so we work around this
- # by wrapping the +sql+ string as a sub-select and ordering in that query.
- order = order_clauses.join(', ').split(',').map { |s| s.strip }.reject(&:blank?)
- order = order.zip((0...order.size).to_a).map { |s,i| "id_list.alias_#{i} #{'DESC' if s =~ /\bdesc$/i}" }.join(', ')
-
- query = build_query \
- "SELECT #{select_clauses.kind_of?(::Array) ? select_clauses.join("") : select_clauses.to_s}",
- "FROM #{from_clauses}",
- (joins(self) unless joins(self).blank? ),
- ("WHERE #{where_clauses.join(" AND ")}" unless wheres.blank? ),
- ("GROUP BY #{group_clauses.join(', ')}" unless groupings.blank? ),
- ("HAVING #{having_clauses.join(', ')}" unless havings.blank? ),
- ("#{locked}" unless locked.blank? )
- build_query \
- "SELECT * FROM (#{query}) AS id_list",
- "ORDER BY #{order}",
- ("LIMIT #{taken}" unless taken.blank? ),
- ("OFFSET #{skipped}" unless skipped.blank? )
-
- else
- build_query \
- "SELECT #{select_clauses.join(', ')}",
- "FROM #{from_clauses}",
- (joins(self) unless joins(self).blank? ),
- ("WHERE #{where_clauses.join(" AND ")}" unless wheres.blank? ),
- ("GROUP BY #{group_clauses.join(', ')}" unless groupings.blank? ),
- ("HAVING #{having_clauses.join(', ')}" unless havings.blank? ),
- ("ORDER BY #{order_clauses.join(', ')}" unless orders.blank? ),
- ("LIMIT #{taken}" unless taken.blank? ),
- ("OFFSET #{skipped}" unless skipped.blank? ),
- ("#{locked}" unless engine.adapter_name =~ /SQLite/ || locked.blank?)
- end
+ def compiler
+ @compiler ||= "Arel::SqlCompiler::#{engine.adapter_name}Compiler".constantize.new(self)
end
- def inclusion_predicate_sql
- "IN"
+ def to_sql(formatter = Sql::SelectStatement.new(self))
+ formatter.select compiler.select_sql, self
end
def christener
@christener ||= Sql::Christener.new
end
- protected
-
- def build_query(*parts)
- parts.compact.join(" ")
- end
-
- def from_clauses
- sources.blank? ? table_sql(Sql::TableReference.new(self)) : sources
- end
-
- def select_clauses
- attributes.collect { |a| a.to_sql(Sql::SelectClause.new(self)) }
- end
-
- def where_clauses
- wheres.collect { |w| w.to_sql(Sql::WhereClause.new(self)) }
- end
-
- def group_clauses
- groupings.collect { |g| g.to_sql(Sql::GroupClause.new(self)) }
- end
-
- def having_clauses
- havings.collect { |g| g.to_sql(Sql::HavingClause.new(self)) }
- end
-
- def order_clauses
- orders.collect { |o| o.to_sql(Sql::OrderClause.new(self)) }
- end
-
- def using_distinct_on?
- select_clauses.any? { |x| x =~ /DISTINCT ON/ }
+ def inclusion_predicate_sql
+ "IN"
end
end
end
diff --git a/lib/arel/engines/sql/relations/table.rb b/lib/arel/engines/sql/relations/table.rb
index a409d8223f..9ea07a00a1 100644
--- a/lib/arel/engines/sql/relations/table.rb
+++ b/lib/arel/engines/sql/relations/table.rb
@@ -15,6 +15,14 @@ module Arel
else
@engine = options # Table.new('foo', engine)
end
+
+ if @engine.connection
+ begin
+ require "lib/arel/engines/sql/compilers/#{@engine.adapter_name.downcase}_compiler"
+ rescue LoadError
+ raise "#{@engine.adapter_name} is not supported by Arel."
+ end
+ end
end
def as(table_alias)
diff --git a/lib/arel/engines/sql/relations/utilities/externalization.rb b/lib/arel/engines/sql/relations/utilities/externalization.rb
index 7f937e8423..a0230e90f3 100644
--- a/lib/arel/engines/sql/relations/utilities/externalization.rb
+++ b/lib/arel/engines/sql/relations/utilities/externalization.rb
@@ -3,7 +3,7 @@ module Arel
include Recursion::BaseCase
def table_sql(formatter = Sql::TableReference.new(relation))
- formatter.select relation.select_sql, self
+ formatter.select relation.compiler.select_sql, self
end
# REMOVEME
--
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