diff --git a/src/ZucchiDoctrine/Query/QueryBuilderTrait.php b/src/ZucchiDoctrine/Query/QueryBuilderTrait.php
index cb9d31f..1803de9 100755
--- a/src/ZucchiDoctrine/Query/QueryBuilderTrait.php
+++ b/src/ZucchiDoctrine/Query/QueryBuilderTrait.php
@@ -37,131 +37,163 @@ protected function addWhere($qb, $where)
     {
         // process the $where
         if (is_string($where)) {
-            // straight DQL string
+            // @todo: test and provide security for straight DQL string
             $qb->andWhere($where);
+
         } elseif (is_array($where) && count($where)) {
-            // create where expression
-            $whereExp = $qb->expr()->andx();
-            $params = array();
+
+            $params = array(); // initialise container to store params
+
+            $whereExp = $this->getParts($qb, $where, $params);
             
-            // index for the parameters
-            $i = 0;
+            // only add where expression if actually has parts
+            if (count($whereExp->getParts())) {
+                $qb->where($whereExp);
+            }
             
-            // loop through all the clauses supplied
-            foreach ($where as $col => $val) {
-                
-                if ((is_array($val) && (!isset($val['value']) || (is_string($val['value']) && strlen($val['value']) == 0))) ||
-                     (is_string($val) && (!$val || strlen($val) == 0))
-                ){
-                    // skip if invalid value;
-                    continue;
-                }
-                
-                // check if we've been provided with an operator as well as a value
-                if (!is_array($val)) {
-                    $operator = Expr\Comparison::EQ;
-                    $val = $val;
-                } elseif (count($val) == 1) {
-                    $operator = Expr\Comparison::EQ;
-                    $val = end($val);
-                } else {
-                    $operator = isset($val['operator']) ? $val['operator'] : Expr\Comparison::EQ;
-                    $val = array_key_exists('value', $val) ? $val['value'] : array();
-                    
-                }
-                
-                // set the alias to the default
-                $alias = $this->alias;
+            // set the params from the where clause above
+            $qb->setParameters($params);
+        }
+        
+        return $this;
+    }
 
-                // if col relates to a relation i.e. Role.id
-                // then perform a join and set up the alias and column names
-                if (strpos($col, '.') !== false) {
-                    $parts = explode('.', $col);
-                    $col = array_pop($parts);
-                    $par = $this->alias;
-                    
-                    foreach ($parts AS $rel) {
-                        $alias = strtolower($rel);
-                        $jt = new Expr\Join(Expr\Join::LEFT_JOIN, $par . '.' . $rel, $alias);
-                        if (!strpos($qb->getDql(), $jt->__toString()) !== false) {
-                            $qb->leftJoin($par . '.' . $rel, $alias);    
-                        }    
-                        $par = $alias;
+
+    protected function getParts($qb, $where, &$params = array())
+    {
+        if (array_key_exists('mode', $where) && $where['mode'] == 'or') {
+            $whereExp = $qb->expr()->orX();
+        } else {
+            $whereExp = $qb->expr()->andX();
+        }
+        unset($where['mode']); // unset to allow flat iteration for simpler structures
+
+        // index for the parameters
+        $i = count($params);
+
+        if (array_key_exists('expressions', $where)) {
+            foreach($where['expressions'] as $expression) {
+                $part = $this->getParts($qb, $expression, $params);
+                $whereExp->add($part);
+            }
+            unset($where['expressions']); // unset to allow flat iteration for simpler structures
+        }
+
+        // set fields to iterate over if no fields property assume using remaining elements in $where
+        $fields =  (array_key_exists('fields', $where)) ? $where['fields'] : $where;
+
+        // loop through all the clauses supplied
+        foreach ($fields as $col => $val) {
+
+            if ((is_array($val) && (!isset($val['value']) || (is_string($val['value']) && strlen($val['value']) == 0))) ||
+                (is_string($val) && (!$val || strlen($val) == 0))
+            ){
+                // skip if invalid value;
+                continue;
+            }
+
+            // check if we've been provided with an operator as well as a value
+            if (!is_array($val)) {
+                $operator = Expr\Comparison::EQ;
+                $val = $val;
+            } elseif (count($val) == 1) {
+                $operator = Expr\Comparison::EQ;
+                $val = end($val);
+            } else {
+                $operator = isset($val['operator']) ? $val['operator'] : Expr\Comparison::EQ;
+                $val = array_key_exists('value', $val) ? $val['value'] : array();
+
+            }
+
+            // set the alias to the default
+            $alias = $this->alias;
+
+            // if col relates to a relation i.e. Role.id
+            // then perform a join and set up the alias and column names
+            if (strpos($col, '.') !== false) {
+                $parts = explode('.', $col);
+                $col = array_pop($parts);
+                $par = $this->alias;
+
+                foreach ($parts AS $rel) {
+                    $alias = strtolower($rel);
+                    $jt = new Expr\Join(Expr\Join::LEFT_JOIN, $par . '.' . $rel, $alias);
+                    if (!strpos($qb->getDql(), $jt->__toString()) !== false) {
+                        $qb->leftJoin($par . '.' . $rel, $alias);
                     }
+                    $par = $alias;
                 }
+            }
 
-                if ($val instanceof Expr\Base) {
-                    $whereExp->add($val);
-                } else {
-                    // process sets a little differently
-                    if (!is_array($val)) {
-                        $val = array($val);
-                    }
-                    switch ($operator) {
-                        case 'regexp':
-                            $whereExp->add("REGEXP(" . $alias . '.' . $col . ",'" . $val[0] . "') = 1");
-                            break;
-                        case 'between':
-                            if (count($val) == 2) {
-                                // $value should now be an array with 2 values
-                                $expr = new Expr();
-                                $from = (is_int($val[0])) ? $val[0] : "'" . $val[0] . "'";
-                                $to = (is_int($val[1])) ? $val[1] : "'" . $val[1] . "'";
-
-                                $stmt = $expr->between($alias . '.' . $col, $from, $to);
-                                $whereExp->add($stmt);
-                            }
-                            break;
-                        case 'is':
+            if ($val instanceof Expr\Base) {
+                $whereExp->add($val);
+            } else {
+                // process sets a little differently
+                if (!is_array($val)) {
+                    $val = array($val);
+                }
+                switch (strtolower($operator)) {
+                    case 'regexp':
+                        $whereExp->add("REGEXP(" . $alias . '.' . $col . ",'" . $val[0] . "') = 1");
+                        break;
+                    case 'between':
+                        if (count($val) == 2) {
+                            // $value should now be an array with 2 values
                             $expr = new Expr();
-                            $method = 'is' . ucfirst($val[0]);
-                            if (method_exists($expr, $method)) {
-                                $stmt = $expr->{$method}($alias . '.' . $col);
-                                $whereExp->add($stmt);
-                            }
-                            break;
-                        default:
-                            // this holds the subquery for this field, each component being an OR
-                            $subWhereExp = $qb->expr()->orX();
-
-                            foreach ($val as $value) {
-                                if ($value == null) {
-                                    $cmpValue = 'NULL';
-                                } else {
-                                    $cmpValue = '?' . $i;
-
-                                    // wrap LIKE values
-                                    if ($operator == 'like') {
-                                        $value = '%' . trim($value, '%') . '%';
-                                    }
-
-                                    // add the parameter value into the parameters stack
-                                    $params[$i] = $value;
-                                    $i++;
+                            $from = (is_int($val[0])) ? $val[0] : "'" . $val[0] . "'";
+                            $to = (is_int($val[1])) ? $val[1] : "'" . $val[1] . "'";
+
+                            $stmt = $expr->between($alias . '.' . $col, $from, $to);
+                            $whereExp->add($stmt);
+                        }
+                        break;
+                    case 'is':
+                        $expr = new Expr();
+                        $method = 'is' . ucfirst($val[0]);
+                        if (method_exists($expr, $method)) {
+                            $stmt = $expr->{$method}($alias . '.' . $col);
+                            $whereExp->add($stmt);
+                        }
+                        break;
+                    default:
+                        // this holds the subquery for this field, each component being an OR
+                        $subWhereExp = $qb->expr()->orX();
+
+                        foreach ($val as $value) {
+                            if ($value == null) {
+                                $cmpValue = 'NULL';
+                            } else {
+                                $cmpValue = '?' . $i;
+
+                                // wrap IN/NOT IN values with parenthesis
+                                if ($operator == 'in' || $operator == 'not in') {
+                                    $cmpValue = '(' . trim($cmpValue, ')') . ')';
                                 }
 
-                                $comparison = new Expr\Comparison($alias . '.' . $col, $operator, $cmpValue);
-                                $subWhereExp->add($comparison);
+                                // wrap LIKE values
+                                if ($operator == 'like') {
+                                    $value = '%' . trim($value, '%') . '%';
+                                }
+
+                                // add the parameter value into the parameters stack
+                                $params[$i] = $value;
+                                $i++;
                             }
 
-                            // add in the subquery as an AND
-                            $whereExp->add($subWhereExp);
-                            break;
+                            $comparison = new Expr\Comparison($alias . '.' . $col, $operator, $cmpValue);
+                            $subWhereExp->add($comparison);
+                        }
+
+                        // add in the subquery as an AND
+                        $whereExp->add($subWhereExp);
+                        break;
 
-                    }
                 }
             }
-            
-            // only add where expression if actually has parts
-            if (count($whereExp->getParts())) {
-                $qb->where($whereExp);
-            }
-            
-            // set the params from the where clause above
-            $qb->setParameters($params);
         }
-        
-        return $this;
+
+        return $whereExp;
+
     }
     
     /**