diff --git a/Doctrine/Connection.php b/Doctrine/Connection.php
index c89d4ba79..a28dc6280 100644
--- a/Doctrine/Connection.php
+++ b/Doctrine/Connection.php
@@ -28,16 +28,20 @@
  */
 abstract class Doctrine_Connection extends Doctrine_Configurable implements Countable, IteratorAggregate {
     /**
-     * @var $dbh                            the database handler
+     * @var $dbh                                the database handler
      */
     private $dbh;
     /**
-     * @var Doctrine_Transaction $tx        the transaction object
+     * @var Doctrine_Transaction $transaction   the transaction object
      */
-    private $tx;
+    private $transaction;
     /**
-     * @var array $tables                   an array containing all the initialized Doctrine_Table objects
-     *                                      keys representing Doctrine_Table component names and values as Doctrine_Table objects
+     * @var Doctrine_UnitOfWork $unitOfWork     the unit of work object
+     */
+    private $unitOfWork;
+    /**
+     * @var array $tables                       an array containing all the initialized Doctrine_Table objects
+     *                                          keys representing Doctrine_Table component names and values as Doctrine_Table objects
      */
     protected $tables           = array();
     /**
@@ -49,7 +53,8 @@ abstract class Doctrine_Connection extends Doctrine_Configurable implements Coun
     public function __construct(Doctrine_Manager $manager,PDO $pdo) {
         $this->dbh   = $pdo;
 
-        $this->tx    = new Doctrine_Transaction($this);
+        $this->transaction  = new Doctrine_Transaction($this);
+        $this->unitOfWork   = new Doctrine_UnitOfWork($this);
 
         $this->setParent($manager);
 
@@ -58,6 +63,16 @@ abstract class Doctrine_Connection extends Doctrine_Configurable implements Coun
 
         $this->getAttribute(Doctrine::ATTR_LISTENER)->onOpen($this);
     }
+    /**
+     * getUnitOfWork
+     *
+     * returns the unit of work object
+     *
+     * @return Doctrine_UnitOfWork
+     */
+    public function getUnitOfWork() {
+        return $this->unitOfWork;                                	
+    }
     /**
      * getTransaction
      *
@@ -66,7 +81,7 @@ abstract class Doctrine_Connection extends Doctrine_Configurable implements Coun
      * @return Doctrine_Transaction
      */
     public function getTransaction() {
-        return $this->tx;
+        return $this->transaction;
     }
     /**
      * returns the manager that created this connection
@@ -211,119 +226,6 @@ abstract class Doctrine_Connection extends Doctrine_Configurable implements Coun
     public function create($name) {
         return $this->getTable($name)->create();
     }
-
-
-    /**
-     * buildFlushTree
-     * builds a flush tree that is used in transactions
-     *
-     * @return array
-     */
-    public function buildFlushTree(array $tables) {
-        $tree = array();
-        foreach($tables as $k => $table) {
-            $k = $k.$table;
-            if( ! ($table instanceof Doctrine_Table))
-                $table = $this->getTable($table);
-
-            $nm     = $table->getComponentName();
-
-            $index  = array_search($nm,$tree);
-            if($index === false) {
-                $tree[] = $nm;
-                $index  = max(array_keys($tree));
-
-                //print "$k -- adding <b>$nm</b>...<br \>";
-            }
-
-            $rels = $table->getRelations();
-            
-            // group relations
-            
-            foreach($rels as $key => $rel) {
-                if($rel instanceof Doctrine_ForeignKey) {
-                    unset($rels[$key]);
-                    array_unshift($rels, $rel);
-                }
-            }
-
-            foreach($rels as $rel) {
-                $name   = $rel->getTable()->getComponentName();
-                $index2 = array_search($name,$tree);
-                $type   = $rel->getType();
-
-                // skip self-referenced relations
-                if($name === $nm)
-                    continue;
-
-                if($rel instanceof Doctrine_ForeignKey) {
-                    if($index2 !== false) {
-                        if($index2 >= $index)
-                            continue;
-
-                        unset($tree[$index]);
-                        array_splice($tree,$index2,0,$nm);
-                        $index = $index2;
-                        
-                        //print "$k -- pushing $nm into $index2...<br \>";
-
-                    } else {
-                        $tree[] = $name;
-                        //print "$k -- adding $nm :$name...<br>";
-                    }
-
-                } elseif($rel instanceof Doctrine_LocalKey) {
-                    if($index2 !== false) {
-                        if($index2 <= $index)
-                            continue;
-
-                        unset($tree[$index2]);
-                        array_splice($tree,$index,0,$name);
-
-                        //print "$k -- pushing $name into <b>$index</b>...<br \>";
-
-                    } else {
-                        //array_splice($tree, $index, 0, $name);
-                        array_unshift($tree,$name);
-                        $index++;
-
-                        //print "$k -- pushing <b>$name</b> into 0...<br \>";
-                    }
-                } elseif($rel instanceof Doctrine_Association) {
-                    $t = $rel->getAssociationFactory();
-                    $n = $t->getComponentName();
-                    
-                    if($index2 !== false)
-                        unset($tree[$index2]);
-                    
-                    array_splice($tree,$index, 0,$name);
-                    $index++;
-
-                    $index3 = array_search($n,$tree);
-
-                    if($index3 !== false) {
-                        if($index3 >= $index)
-                            continue;
-
-                        unset($tree[$index]);
-                        array_splice($tree,$index3,0,$n);
-                        $index = $index2;
-
-                        //print "$k -- pushing $nm into $index3...<br \>";
-
-                    } else {
-                        $tree[] = $n;
-                        //print "$k -- adding $nm :$name...<br>";
-                    }
-                }
-                //print_r($tree);
-            }
-            //print_r($tree);
-
-        }
-        return array_values($tree);
-    }
-
     /**
      * flush                        
      * saves all the records from all tables
@@ -343,7 +245,7 @@ abstract class Doctrine_Connection extends Doctrine_Configurable implements Coun
      * @return void
      */
     private function saveAll() {
-        $tree = $this->buildFlushTree($this->tables);
+        $tree = $this->unitOfWork->buildFlushTree($this->tables);
 
         foreach($tree as $name) {
             $table = $this->tables[$name];
@@ -397,7 +299,7 @@ abstract class Doctrine_Connection extends Doctrine_Configurable implements Coun
      * @return integer
      */
     public function getTransactionLevel() {
-        return $this->tx->getTransactionLevel();
+        return $this->transaction->getTransactionLevel();
     }
     /**
      * beginTransaction
@@ -405,7 +307,7 @@ abstract class Doctrine_Connection extends Doctrine_Configurable implements Coun
      * @return void
      */
     public function beginTransaction() {
-        $this->tx->beginTransaction();
+        $this->transaction->beginTransaction();
     }
     /**
      * commits the current transaction
@@ -415,7 +317,7 @@ abstract class Doctrine_Connection extends Doctrine_Configurable implements Coun
      * @return void
      */
     public function commit() {
-        $this->tx->commit();
+        $this->transaction->commit();
     }
     /**
      * rollback
@@ -427,7 +329,7 @@ abstract class Doctrine_Connection extends Doctrine_Configurable implements Coun
      * @return void
      */
     public function rollback() {
-        $this->tx->rollback();
+        $this->transaction->rollback();
     }
     /**
      * returns maximum identifier values
@@ -492,11 +394,11 @@ abstract class Doctrine_Connection extends Doctrine_Configurable implements Coun
     public function save(Doctrine_Record $record) {
         switch($record->getState()):
             case Doctrine_Record::STATE_TDIRTY:
-                $this->tx->addInsert($record);
+                $this->transaction->addInsert($record);
             break;
             case Doctrine_Record::STATE_DIRTY:
             case Doctrine_Record::STATE_PROXY:
-                $this->tx->addUpdate($record);
+                $this->transaction->addUpdate($record);
             break;
             case Doctrine_Record::STATE_CLEAN:
             case Doctrine_Record::STATE_TCLEAN:
@@ -657,7 +559,7 @@ abstract class Doctrine_Connection extends Doctrine_Configurable implements Coun
                 $this->beginTransaction();
 
                 $this->deleteComposites($record);
-                $this->tx->addDelete($record);
+                $this->transaction->addDelete($record);
 
                 $this->commit();
                 return true;
diff --git a/Doctrine/UnitOfWork.php b/Doctrine/UnitOfWork.php
new file mode 100644
index 000000000..98ac95185
--- /dev/null
+++ b/Doctrine/UnitOfWork.php
@@ -0,0 +1,140 @@
+<?php
+/* 
+ *  $Id$
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This software consists of voluntary contributions made by many individuals
+ * and is licensed under the LGPL. For more information, see
+ * <http://www.phpdoctrine.com>.
+ */
+
+/**
+ * Doctrine_Transaction
+ *
+ * @package     Doctrine ORM
+ * @url         www.phpdoctrine.com
+ * @license     LGPL
+ */
+class Doctrine_UnitOfWork implements IteratorAggregate, Countable {
+    /**
+     * @var Doctrine_Connection $conn       the connection object
+     */
+    private $connection;
+
+    /**
+     * the constructor
+     *
+     * @param Doctrine_Connection $conn
+     */
+    public function __construct(Doctrine_Connection $conn) {
+        $this->conn = $conn;
+    }
+
+    /**
+     * buildFlushTree
+     * builds a flush tree that is used in transactions
+     *
+     * @return array
+     */
+    public function buildFlushTree(array $tables) {
+        $tree = array();
+        foreach($tables as $k => $table) {
+            $k = $k.$table;
+            if( ! ($table instanceof Doctrine_Table))
+                $table = $this->conn->getTable($table);
+
+            $nm     = $table->getComponentName();
+
+            $index  = array_search($nm,$tree);
+
+            if($index === false) {
+                $tree[] = $nm;
+                $index  = max(array_keys($tree));
+            }
+
+            $rels = $table->getRelations();
+            
+            // group relations
+            
+            foreach($rels as $key => $rel) {
+                if($rel instanceof Doctrine_ForeignKey) {
+                    unset($rels[$key]);
+                    array_unshift($rels, $rel);
+                }
+            }
+
+            foreach($rels as $rel) {
+                $name   = $rel->getTable()->getComponentName();
+                $index2 = array_search($name,$tree);
+                $type   = $rel->getType();
+
+                // skip self-referenced relations
+                if($name === $nm)
+                    continue;
+
+                if($rel instanceof Doctrine_ForeignKey) {
+                    if($index2 !== false) {
+                        if($index2 >= $index)
+                            continue;
+
+                        unset($tree[$index]);
+                        array_splice($tree,$index2,0,$nm);
+                        $index = $index2;
+                    } else {
+                        $tree[] = $name;
+                    }
+
+                } elseif($rel instanceof Doctrine_LocalKey) {
+                    if($index2 !== false) {
+                        if($index2 <= $index)
+                            continue;
+
+                        unset($tree[$index2]);
+                        array_splice($tree,$index,0,$name);
+                    } else {
+                        array_unshift($tree,$name);
+                        $index++;
+                    }
+                } elseif($rel instanceof Doctrine_Association) {
+                    $t = $rel->getAssociationFactory();
+                    $n = $t->getComponentName();
+                    
+                    if($index2 !== false)
+                        unset($tree[$index2]);
+                    
+                    array_splice($tree,$index, 0,$name);
+                    $index++;
+
+                    $index3 = array_search($n,$tree);
+
+                    if($index3 !== false) {
+                        if($index3 >= $index)
+                            continue;
+
+                        unset($tree[$index]);
+                        array_splice($tree,$index3,0,$n);
+                        $index = $index2;
+                    } else {
+                        $tree[] = $n;
+                    }
+                }
+            }
+        }
+        return array_values($tree);
+    }
+
+    public function getIterator() { }
+
+    public function count() { }
+}
diff --git a/tests/ConnectionTestCase.php b/tests/ConnectionTestCase.php
index 0d89742a8..e3aa5c332 100644
--- a/tests/ConnectionTestCase.php
+++ b/tests/ConnectionTestCase.php
@@ -2,7 +2,7 @@
 require_once("UnitTestCase.php");
 class Doctrine_ConnectionTestCase extends Doctrine_UnitTestCase {
 
-    public function testBuildFlushTree() {
+    public function testbuildFlushTree() {
         $correct = array("Task","ResourceType","Resource","Assignment","ResourceReference");
 
         // new model might switch some many-to-many components (NO HARM!)
@@ -17,89 +17,89 @@ class Doctrine_ConnectionTestCase extends Doctrine_UnitTestCase {
 
         $task = new Task();
 
-        $tree = $this->connection->buildFlushTree(array("Task"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Task"));
         $this->assertEqual($tree,array("Resource","Task","Assignment"));
 
-        $tree = $this->connection->buildFlushTree(array("Task","Resource"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Task","Resource"));
         $this->assertEqual($tree,$correct);
 
-        $tree = $this->connection->buildFlushTree(array("Task","Assignment","Resource"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Task","Assignment","Resource"));
         $this->assertEqual($tree,$correct);
 
-        $tree = $this->connection->buildFlushTree(array("Assignment","Task","Resource"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Assignment","Task","Resource"));
 
         $this->assertEqual($tree,$correct2);
 
 
         $correct = array("Forum_Category","Forum_Board","Forum_Thread");
 
-        $tree = $this->connection->buildFlushTree(array("Forum_Board"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Board"));
         $this->assertEqual($tree, $correct);
-        $tree = $this->connection->buildFlushTree(array("Forum_Category","Forum_Board"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Category","Forum_Board"));
         $this->assertEqual($tree, $correct);
 
         $correct = array("Forum_Category","Forum_Board","Forum_Thread","Forum_Entry");
 
-        $tree = $this->connection->buildFlushTree(array("Forum_Entry","Forum_Board"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Entry","Forum_Board"));
         $this->assertEqual($tree, $correct);
-        $tree = $this->connection->buildFlushTree(array("Forum_Board","Forum_Entry"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Board","Forum_Entry"));
         $this->assertEqual($tree, $correct);
 
-        $tree = $this->connection->buildFlushTree(array("Forum_Thread","Forum_Board"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Thread","Forum_Board"));
         $this->assertEqual($tree, $correct);
-        $tree = $this->connection->buildFlushTree(array("Forum_Board","Forum_Thread"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Board","Forum_Thread"));
         $this->assertEqual($tree, $correct);
 
-        $tree = $this->connection->buildFlushTree(array("Forum_Board","Forum_Thread","Forum_Entry"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Board","Forum_Thread","Forum_Entry"));
         $this->assertEqual($tree, $correct);
-        $tree = $this->connection->buildFlushTree(array("Forum_Board","Forum_Entry","Forum_Thread"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Board","Forum_Entry","Forum_Thread"));
         $this->assertEqual($tree, $correct);
 
-        $tree = $this->connection->buildFlushTree(array("Forum_Entry","Forum_Board","Forum_Thread"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Entry","Forum_Board","Forum_Thread"));
         $this->assertEqual($tree, $correct);
-        $tree = $this->connection->buildFlushTree(array("Forum_Entry","Forum_Thread","Forum_Board"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Entry","Forum_Thread","Forum_Board"));
         $this->assertEqual($tree, $correct);
 
-        $tree = $this->connection->buildFlushTree(array("Forum_Thread","Forum_Board","Forum_Entry"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Thread","Forum_Board","Forum_Entry"));
         $this->assertEqual($tree, $correct);
-        $tree = $this->connection->buildFlushTree(array("Forum_Thread","Forum_Entry","Forum_Board"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Thread","Forum_Entry","Forum_Board"));
         $this->assertEqual($tree, $correct);
 
 
         $this->assertEqual($tree, $correct);
-        $tree = $this->connection->buildFlushTree(array("Forum_Board","Forum_Thread","Forum_Category"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Board","Forum_Thread","Forum_Category"));
         $this->assertEqual($tree, $correct);
-        $tree = $this->connection->buildFlushTree(array("Forum_Category","Forum_Thread","Forum_Board"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Category","Forum_Thread","Forum_Board"));
         $this->assertEqual($tree, $correct);
-        $tree = $this->connection->buildFlushTree(array("Forum_Thread","Forum_Board","Forum_Category"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Thread","Forum_Board","Forum_Category"));
         $this->assertEqual($tree, $correct);
 
-        $tree = $this->connection->buildFlushTree(array("Forum_Board","Forum_Thread","Forum_Category","Forum_Entry"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Board","Forum_Thread","Forum_Category","Forum_Entry"));
         $this->assertEqual($tree, $correct);
-        $tree = $this->connection->buildFlushTree(array("Forum_Board","Forum_Thread","Forum_Entry","Forum_Category"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Board","Forum_Thread","Forum_Entry","Forum_Category"));
         $this->assertEqual($tree, $correct);
-        $tree = $this->connection->buildFlushTree(array("Forum_Board","Forum_Category","Forum_Thread","Forum_Entry"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Board","Forum_Category","Forum_Thread","Forum_Entry"));
         $this->assertEqual($tree, $correct);
 
-        $tree = $this->connection->buildFlushTree(array("Forum_Entry","Forum_Thread","Forum_Board","Forum_Category"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Entry","Forum_Thread","Forum_Board","Forum_Category"));
         $this->assertEqual($tree, $correct);
-        $tree = $this->connection->buildFlushTree(array("Forum_Entry","Forum_Thread","Forum_Category","Forum_Board"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Entry","Forum_Thread","Forum_Category","Forum_Board"));
         $this->assertEqual($tree, $correct);
-        $tree = $this->connection->buildFlushTree(array("Forum_Entry","Forum_Category","Forum_Board","Forum_Thread"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Entry","Forum_Category","Forum_Board","Forum_Thread"));
         $this->assertEqual($tree, $correct);
 
-        $tree = $this->connection->buildFlushTree(array("Forum_Thread","Forum_Category","Forum_Board","Forum_Entry"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Thread","Forum_Category","Forum_Board","Forum_Entry"));
         $this->assertEqual($tree, $correct);
-        $tree = $this->connection->buildFlushTree(array("Forum_Thread","Forum_Entry","Forum_Category","Forum_Board"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Thread","Forum_Entry","Forum_Category","Forum_Board"));
         $this->assertEqual($tree, $correct);
-        $tree = $this->connection->buildFlushTree(array("Forum_Thread","Forum_Board","Forum_Entry","Forum_Category"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Thread","Forum_Board","Forum_Entry","Forum_Category"));
         $this->assertEqual($tree, $correct);
 
-        $tree = $this->connection->buildFlushTree(array("Forum_Category","Forum_Entry","Forum_Board","Forum_Thread"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Category","Forum_Entry","Forum_Board","Forum_Thread"));
         $this->assertEqual($tree, $correct);
-        $tree = $this->connection->buildFlushTree(array("Forum_Category","Forum_Thread","Forum_Entry","Forum_Board"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Category","Forum_Thread","Forum_Entry","Forum_Board"));
         $this->assertEqual($tree, $correct);
-        $tree = $this->connection->buildFlushTree(array("Forum_Category","Forum_Board","Forum_Thread","Forum_Entry"));
+        $tree = $this->connection->getUnitOfWork()->buildFlushTree(array("Forum_Category","Forum_Board","Forum_Thread","Forum_Entry"));
         $this->assertEqual($tree, $correct);
 
     }