diff --git a/common/Definition/DatabaseEngineRequirements.php b/common/Definition/DatabaseEngine/Requirements.php
similarity index 62%
rename from common/Definition/DatabaseEngineRequirements.php
rename to common/Definition/DatabaseEngine/Requirements.php
index 9999fac..2a68a78 100644
--- a/common/Definition/DatabaseEngineRequirements.php
+++ b/common/Definition/DatabaseEngine/Requirements.php
@@ -1,7 +1,7 @@
 <?php
-namespace Aldarien\Common\Definition;
+namespace Aldarien\Common\Definition\DatabaseEngine;
 
-interface DatabaseEngineRequirements {
+interface Requirements {
   public function dsnSpecs(): array;
   public function getDSN(object $config): string;
   public function hasUser(): bool;
diff --git a/common/Factory/Model.php b/common/Factory/Model.php
index 612e9ca..18247f9 100644
--- a/common/Factory/Model.php
+++ b/common/Factory/Model.php
@@ -127,44 +127,20 @@ class Model {
     if ($this->conditions == null) {
       $this->conditions = [];
     }
-    $this->conditions = array_merge($this->conditions, $conditions);
+    foreach ($conditions as $condition) {
+      $this->addCondition($condition);
+    }
     return $this;
   }
+  protected function addCondition(Condition $condition) {
+    $this->conditions []= $condition;
+  }
   protected function parseWhere(ORM $orm): ORM {
     if ($this->conditions == null or count($this->conditions) == 0) {
       return $orm;
     }
     foreach ($this->conditions as $condition) {
-      $method = 'where';
-      $op = '=';
-      if (isset($condition[2])) {
-        $op = strtolower($condition[2]);
-      }
-      if (isset($condition['operator'])) {
-        $op = strtolower($condition['operator']);
-      }
-      $mod = ['=' => '', '>' => 'Gt', '>=' => 'Gte', '<' => 'Lt', '<=' => 'Lte', '!=' => 'NotEqual'];
-      if (isset($mod[$op])) {
-        $method .= $mod[$op];
-      } else {
-        switch (strtolower($op)) {
-          case 'raw':
-            $method = 'rawWhere';
-            break;
-          case 'like':
-            $method = 'whereLike';
-            break;
-        }
-      }
-      $column = $condition[0];
-      if (isset($condition['column'])) {
-        $column = $condition['column'];
-      }
-      $value = $condition[1];
-      if (isset($condition['value'])) {
-        $value = $condition['value'];
-      }
-      $orm = $orm->{$method}($column, $value);
+      $orm = $condition->build($orm);
     }
     return $orm;
   }
diff --git a/src/Factory/Condition.php b/src/Factory/Condition.php
new file mode 100644
index 0000000..91d2d01
--- /dev/null
+++ b/src/Factory/Condition.php
@@ -0,0 +1,54 @@
+<?php
+namespace Aldarien\Models\Factory;
+
+class Condition {
+  protected $table;
+  protected $column;
+  protected $operator;
+  protected $value;
+  protected $alias;
+
+  public function setTable(string $table): Condition {
+    $this->table = $table;
+    return $this;
+  }
+  public function setColumn(string $column): Condition {
+    $this->column = $column;
+    return $this;
+  }
+  public function setOperator(Operator $operator): Condition {
+    $this->operator = $operator;
+    return $this;
+  }
+  public function setValue($value): Condition {
+    $this->value = $value;
+    return $this;
+  }
+  public function setAlias(string $alias): Condition {
+    $this->alias = $alias;
+    return $this;
+  }
+
+  public function fullColumn(): string {
+    $str = [];
+    if ($this->table != null) {
+      $str []= $this->table;
+    }
+    $str []= $this->column;
+    return implode('.', $str);
+  }
+  public function build(ORM $orm): ORM {
+    $method = $this->operator->method();
+    $params = [
+      $this->fullColumn()
+    ];
+    if ($this->operator->hasValue()) {
+      $params []= $this->value;
+    }
+    if ($this->alias != null) {
+      $params []= $this->alias;
+    }
+    $orm = call_user_func_array([$orm, $method], $params);
+    return $orm;
+  }
+}
diff --git a/src/Factory/Operator.php b/src/Factory/Operator.php
new file mode 100644
index 0000000..7bffb67
--- /dev/null
+++ b/src/Factory/Operator.php
@@ -0,0 +1,107 @@
+<?php
+namespace Aldarien\Models\Factory;
+
+class Operator {
+  protected $value;
+
+  public function __construct(string $operator) {
+    $this->setOperator($operator);
+  }
+  public function setOperator(string $operator) {
+    if (!$this->isValid($operator)) {
+      throw new \InvalidArgumentException($operator . ' is not a valid operator.');
+    }
+    $this->value = strtolower($operator);
+  }
+  protected function isValid(string $operator): bool {
+    switch (strtolower($operator)) {
+      case '=':
+      case 'eq':
+      case '!=':
+      case 'neq':
+      case '<':
+      case 'lt':
+      case '<=':
+      case 'lte':
+      case '>':
+      case 'gt':
+      case '>=':
+      case 'gte':
+      case 'like':
+      case 'not like':
+      case 'in':
+      case 'not in':
+      case 'null':
+      case 'not null':
+        return true;
+    }
+    return false;
+  }
+  public function method(): string {
+    $method = 'where';
+    switch ($this->value) {
+      case '!=':
+      case 'neq':
+        $method .= '_not_equal';
+        break;
+      case '<':
+      case 'lt':
+        $method .= '_lt';
+        break;
+      case '<=':
+      case 'lte':
+        $method .= '_lte';
+        break;
+      case '>':
+      case 'gt':
+        $method .= '_gt';
+        break;
+      case '>=':
+      case 'gte':
+        $method .= '_gte';
+        break;
+      case 'like':
+        $method .= '_like';
+        break;
+      case 'not like':
+        $method .= '_not_like';
+        break;
+      case 'in':
+        $method .= '_in';
+        break;
+      case 'not in':
+        $method .='_not_in';
+        break;
+      case 'null':
+        $method .= '_null';
+        break;
+      case 'not null':
+        $method .= '_not_null';
+        break;
+    }
+    return $method;
+  }
+  public function hasValue(): bool {
+    switch ($this->value) {
+      case '=':
+      case 'eq':
+      case '!=':
+      case 'neq':
+      case '<':
+      case 'lt':
+      case '<=':
+      case 'lte':
+      case '>':
+      case 'gt':
+      case '>=':
+      case 'gte':
+      case 'like':
+      case 'not like':
+      case 'in':
+      case 'in':
+      case 'not in':
+        return true;
+    }
+    return false;
+  }
+}
diff --git a/src/MySQLRequirements.php b/src/MySQLRequirements.php
index 2382eaa..9558068 100644
--- a/src/MySQLRequirements.php
+++ b/src/MySQLRequirements.php
@@ -1,7 +1,7 @@
 <?php
 namespace Aldarien\Models;
 
-use Aldarien\Common\Definition\DatabaseEngineRequirements as EngineRequirementsInterface;
+use Aldarien\Common\Definition\DatabaseEngine\Requirements as EngineRequirementsInterface;
 
 class MySQLRequirements implements EngineRequirementsInterface {
   public function dsnSpecs(): array {