diff --git a/common/persistence/class.SqlPersistence.php b/common/persistence/class.SqlPersistence.php
index db1d1fa0f..5519fc18c 100755
--- a/common/persistence/class.SqlPersistence.php
+++ b/common/persistence/class.SqlPersistence.php
@@ -21,6 +21,7 @@
  * @author 
  */
 
+use Doctrine\DBAL\DBALException;
 /**
  * Persistence base on SQL
  */
@@ -32,6 +33,7 @@ class common_persistence_SqlPersistence extends common_persistence_Persistence
      * @param array $params
      * @param array $types
      * @return int number of updated rows
+     * @throws DBALException
      */
     public function exec($statement, array $params = [], array $types = [])
     {
@@ -60,6 +62,7 @@ public function getPlatForm(){
      * @param array $data
      * @param array $types
      * @return int number of updated rows
+     * @throws DBALException
      */
     public function insert($tableName, array $data, array $types = [])
     {
@@ -96,6 +99,7 @@ public function updateMultiple($table, array $data)
      * @param string $statement
      * @param array $params
      * @return \Doctrine\DBAL\Driver\Statement
+     * @throws DBALException
      */
     public function query($statement, $params = [], array $types = [])
     {
diff --git a/common/persistence/sql/SetupDb.php b/common/persistence/sql/SetupDb.php
index 626cd6c9d..179150a06 100644
--- a/common/persistence/sql/SetupDb.php
+++ b/common/persistence/sql/SetupDb.php
@@ -29,7 +29,7 @@
 use oat\generis\model\kernel\persistence\smoothsql\install\SmoothRdsModel;
 use Doctrine\DBAL\Exception\ConnectionException;
 
-class SetupDb implements LoggerAwareInterface
+class SetupDb extends ConfigurableService implements LoggerAwareInterface
 {
     use LoggerAwareTrait;
 
@@ -78,8 +78,9 @@ private function setupTables(\common_persistence_SqlPersistence $p)
      */
     public function getSchema(\common_persistence_SqlPersistence $p)
     {
+        $smoothRdsModel = new SmoothRdsModel();
         $schema = $p->getSchemaManager()->createSchema();
-        SmoothRdsModel::addSmoothTables($schema);
+        $smoothRdsModel->addSmoothTables($schema);
         $this->addKeyValueStoreTable($schema);
         return $schema;
     }
diff --git a/common/persistence/sql/dbal/class.Driver.php b/common/persistence/sql/dbal/class.Driver.php
index a20ca164b..2107fc099 100755
--- a/common/persistence/sql/dbal/class.Driver.php
+++ b/common/persistence/sql/dbal/class.Driver.php
@@ -17,6 +17,8 @@
  * Copyright (c) 2013 (original work) Open Assessment Technologies SA (under the project TAO-PRODUCT);
  */
 
+use Doctrine\DBAL\DBALException;
+
 /**
  * Dbal Driver 
  * 
@@ -45,7 +47,7 @@ class common_persistence_sql_dbal_Driver implements common_persistence_sql_Drive
      * @param string $id
      * @param array $params
      * @return common_persistence_Persistence|common_persistence_SqlPersistence
-     * @throws \Doctrine\DBAL\DBALException
+     * @throws DBALException
      */
     public function connect($id, array $params)
     {
@@ -71,7 +73,7 @@ public function connect($id, array $params)
      * Endless connection
      *
      * @param $connectionParams
-     * @throws \Doctrine\DBAL\DBALException
+     * @throws DBALException
      */
     protected function persistentConnect($connectionParams)
     {
@@ -106,7 +108,7 @@ protected function persistentConnect($connectionParams)
      * @param $config
      * @return \Doctrine\DBAL\Connection
      *
-     * @throws \Doctrine\DBAL\DBALException
+     * @throws DBALException
      *
      */
     private function getConnection($params, $config)
@@ -157,6 +159,7 @@ public function getSchemaManager()
      * @param array $params
      * @param array $types
      * @return integer number of affected row
+     * @throws DBALException;
      */
     public function exec($statement, $params = [], array $types = [])
     {
@@ -170,6 +173,7 @@ public function exec($statement, $params = [], array $types = [])
      * @param array $params
      * @param array $types
      * @return \Doctrine\DBAL\Driver\Statement
+     * @throws DBALException;
      */
     public function query($statement, $params = [], array $types = [])
     {
@@ -189,7 +193,9 @@ public function quote($parameter, $parameter_type = PDO::PARAM_STR){
     }
     
     /**
-     * @inheritdoc
+     * (non-PHPdoc)
+     * @see common_persistence_sql_Driver::insert()
+     * @throws DBALException;
      */
     public function insert($tableName, array $data, array $types = [])
     {
diff --git a/common/persistence/sql/interface.Driver.php b/common/persistence/sql/interface.Driver.php
index a87e2d1b3..4791c1dc0 100644
--- a/common/persistence/sql/interface.Driver.php
+++ b/common/persistence/sql/interface.Driver.php
@@ -21,11 +21,21 @@
  * @package generis
  *
  */
+
+use Doctrine\DBAL\DBALException;
+
 interface common_persistence_sql_Driver extends common_persistence_Driver
 {
-    
+    /**
+     * @inheritdoc
+     * @throws DBALException;
+     */
     public function query($statement,$params, array $types = []);
-    
+
+    /**
+     * @inheritdoc
+     * @throws DBALException;
+     */
     public function exec($statement,$params, array $types = []);
     
     /**
@@ -35,7 +45,8 @@ public function exec($statement,$params, array $types = []);
      * 
      * @param string $tableName name of the table
      * @param array $data An associative array containing column-value pairs.
-     * @return integer The number of affected rows. 
+     * @return integer The number of affected rows.
+     * @throws DBALException
      */
     public function insert($tableName, array $data, array $types = []);
     
diff --git a/core/kernel/api/NewSqlModelFactory.php b/core/kernel/api/NewSqlModelFactory.php
new file mode 100644
index 000000000..1a83af04c
--- /dev/null
+++ b/core/kernel/api/NewSqlModelFactory.php
@@ -0,0 +1,120 @@
+<?php
+
+/**
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; under version 2
+ * of the License (non-upgradable).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * Copyright (c) 2019 (original work) Open Assessment Technologies SA
+ */
+
+namespace oat\generis\model\kernel\api;
+
+use core_kernel_api_ModelFactory as ModelFactory;
+use Doctrine\DBAL\Schema\Schema;
+use oat\generis\Helper\UuidPrimaryKeyTrait;
+use RuntimeException;
+
+class NewSqlModelFactory extends ModelFactory
+{
+    use UuidPrimaryKeyTrait;
+    
+    /**
+     * @inheritdoc
+     */
+    public function addNewModel($namespace)
+    {
+        $modelId = md5($namespace);
+        if ($this->getPersistence()->insert('models', ['modelid' => $modelId, 'modeluri' => $namespace]) === 0) {
+            throw new RuntimeException('A problem occurred while creating a new model.');
+        }
+        return $modelId;
+    }
+    
+    /**
+     * @inheritdoc
+     */
+    public function prepareStatement($modelId, $subject, $predicate, $object, $lang, $author)
+    {
+        return [
+            'id' => $this->getUniquePrimaryKey(),
+            'modelid' => $modelId,
+            'subject' => $subject,
+            'predicate' => $predicate,
+            'object' => $object,
+            'l_language' => $lang,
+            'author' => $author ?? '',
+            'epoch' => $this->getPersistence()->getPlatForm()->getNowExpression(),
+        ];
+    }
+    
+    /**
+     * @inheritdoc
+     */
+    public function buildModelSqlCondition(array $models)
+    {
+        $models = array_map(
+            function ($a) {
+                return "'" . $a . "'";
+            },
+            $models
+        );
+        return parent::buildModelSqlCondition($models);
+    }
+    
+    /**
+     * @inheritdoc
+     */
+    public function getPropertySortingField()
+    {
+        return 'epoch';
+    }
+    
+    /**
+     * @inheritdoc
+     */
+    public function createModelsTable(Schema $schema)
+    {
+        $table = $schema->createTable('models');
+        
+        $table->addColumn('modelid', 'string', ['length' => 36, 'notnull' => true]);
+        $table->addColumn('modeluri', 'string', ['length' => 255]);
+        
+        $table->setPrimaryKey(['modelid']);
+        
+        return $table;
+    }
+    
+    /**
+     * @inheritdoc
+     */
+    public function createStatementsTable(Schema $schema)
+    {
+        $table = $schema->createTable('statements');
+        
+        $table->addColumn('id', 'string', ['length' => 36, 'notnull' => true]);
+        $table->addColumn('modelid', 'string', ['length' => 23, 'notnull' => true]);
+        $table->addColumn('subject', 'string', ['length' => 255]);
+        $table->addColumn('predicate', 'string', ['length' => 255]);
+        $table->addColumn('object', 'text', []);
+        $table->addColumn('l_language', 'string', ['length' => 255]);
+        $table->addColumn('author', 'string', ['length' => 255]);
+        $table->addColumn('epoch', 'string', ['notnull' => true]);
+        
+        $table->setPrimaryKey(['id']);
+        $table->addIndex(['subject', 'predicate'], 'k_sp');
+        $table->addIndex(['predicate', 'object'], 'k_po');
+        
+        return $table;
+    }
+}
diff --git a/core/kernel/api/RdsModelFactory.php b/core/kernel/api/RdsModelFactory.php
new file mode 100644
index 000000000..f649fdadc
--- /dev/null
+++ b/core/kernel/api/RdsModelFactory.php
@@ -0,0 +1,109 @@
+<?php
+
+/**
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; under version 2
+ * of the License (non-upgradable).
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * Copyright (c) 2019 (original work) Open Assessment Technologies SA
+ */
+
+namespace oat\generis\model\kernel\api;
+
+use core_kernel_api_ModelFactory as ModelFactory;
+use Doctrine\DBAL\Schema\Schema;
+use RuntimeException;
+
+class RdsModelFactory extends ModelFactory
+{
+    /**
+     * @inheritdoc
+     */
+    public function addNewModel($namespace)
+    {
+        $persistence = $this->getPersistence();
+        if ($persistence->insert('models', ['modeluri' => $namespace]) === 0) {
+            throw new RuntimeException('A problem occurred while creating a new model.');
+        }
+
+        // Retrieving the inserted modelid (auto-increment).
+        $result = $persistence->query('select modelid from models where modeluri = ?', [$namespace]);
+        $modelId = $result->fetch();
+        return $modelId['modelid'];
+    }
+    
+    /**
+     * @inheritdoc
+     */
+    public function prepareStatement($modelId, $subject, $predicate, $object, $lang, $author)
+    {
+        return [
+            'modelid' => $modelId,
+            'subject' => $subject,
+            'predicate' => $predicate,
+            'object' => $object,
+            'l_language' => $lang,
+            'author' => $author ?? '',
+            'epoch' => $this->getPersistence()->getPlatForm()->getNowExpression(),
+        ];
+    }
+    
+    /**
+     * @inheritdoc
+     */
+    public function getPropertySortingField()
+    {
+        return 'id';
+    }
+    
+    /**
+     * @inheritdoc
+     */
+    public function createModelsTable(Schema $schema)
+    {
+        // Models table.
+        $table = $schema->createTable('models');
+        
+        $table->addColumn('modelid', 'integer', ['notnull' => true, 'autoincrement' => true]);
+        $table->addColumn('modeluri', 'string', ['length' => 255, 'default' => null]);
+        
+        $table->setPrimaryKey(['modelid']);
+        $table->addOption('engine', 'MyISAM');
+        
+        return $table;
+    }
+    
+    /**
+     * @inheritdoc
+     */
+    public function createStatementsTable(Schema $schema)
+    {
+        $table = $schema->createTable('statements');
+        
+        $table->addColumn('id', 'integer', ['notnull' => true, 'autoincrement' => true]);
+        $table->addColumn('modelid', 'integer', ['notnull' => true, 'default' => 0]);
+        $table->addColumn('subject', 'string', ['length' => 255, 'default' => null]);
+        $table->addColumn('predicate', 'string', ['length' => 255, 'default' => null]);
+        $table->addColumn('object', 'text', ['default' => null, 'notnull' => false]);
+        $table->addColumn('l_language', 'string', ['length' => 255, 'default' => null, 'notnull' => false]);
+        $table->addColumn('author', 'string', ['length' => 255, 'default' => null, 'notnull' => false]);
+        $table->addColumn('epoch', 'string', ['notnull' => null]);
+        
+        $table->setPrimaryKey(['id']);
+        $table->addIndex(['subject', 'predicate'], 'k_sp', [], ['lengths' => [164, 164]]);
+        $table->addIndex(['predicate', 'object'], 'k_po', [], ['lengths' => [164, 164]]);
+        $table->addOption('engine', 'MyISAM');
+        
+        return $table;
+    }
+}
diff --git a/core/kernel/api/class.ModelFactory.php b/core/kernel/api/class.ModelFactory.php
index c47d2dd0d..0c3ba99a3 100644
--- a/core/kernel/api/class.ModelFactory.php
+++ b/core/kernel/api/class.ModelFactory.php
@@ -22,48 +22,61 @@
  
  *
  */
-class core_kernel_api_ModelFactory{
-    
-    
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\DBAL\Schema\Table;
+use common_persistence_SqlPersistence as Persistence;
+use oat\generis\persistence\PersistenceManager;
+use oat\oatbox\log\LoggerAwareTrait;
+use oat\oatbox\service\ConfigurableService;
+
+abstract class core_kernel_api_ModelFactory extends ConfigurableService {
+
+    use LoggerAwareTrait;
+        
+    const SERVICE_ID = __CLASS__;
+    const OPTION_PERSISTENCE = 'persistence';
+    const DEFAULT_AUTHOR = 'http://www.tao.lu/Ontologies/TAO.rdf#installator';
+
     /**
      * @author "Lionel Lecaque, <lionel@taotesting.com>"
      * @param string $namespace
      * @return string
      */
-    private function getModelId($namespace){
-        $dbWrapper = core_kernel_classes_DbWrapper::singleton();
+    public function getModelId($namespace){
+        if (substr($namespace, -1) !== '#') {
+            $namespace .= '#';
+        }
         
         $query = 'SELECT modelid FROM models WHERE (modeluri = ?)';
-        $results = $dbWrapper->query($query, array($namespace));
+        $results = $this->getPersistence()->query($query, array($namespace));
        
         return $results->fetchColumn(0);
 
     }
     
     /**
+     * Creates a new model in the ontology.
      * @author "Lionel Lecaque, <lionel@taotesting.com>"
      * @param string $namespace
+     * @return string|int new added model id
+     * @throws RuntimeException when a problem occurs when creating the new model in db.
      */
-    private function addNewModel($namespace){
-        $dbWrapper = core_kernel_classes_DbWrapper::singleton();
-        $results = $dbWrapper->insert('models', array('modeluri' =>$namespace));
-        
-        
-    }
+    abstract public function addNewModel($namespace);
     
     /**
+     * Creates a new model.
      * @author "Lionel Lecaque, <lionel@taotesting.com>"
      * @param string $namespace
      * @param string $data xml content
+     * @return bool Were triples added?
      */
     public function createModel($namespace, $data){
 
         $modelId = $this->getModelId($namespace);
         if($modelId === false){
-            common_Logger::d('modelId not found, need to add namespace '. $namespace);
-            $this->addNewModel($namespace);
-            //TODO bad way, need to find better
-            $modelId = $this->getModelId($namespace);
+            $this->logInfo('modelId not found, need to add namespace '. $namespace);
+            $modelId = $this->addNewModel($namespace);
         }
         $modelDefinition = new EasyRdf_Graph($namespace);
         if(is_file($data)){
@@ -77,51 +90,119 @@ public function createModel($namespace, $data){
         
         $data = $modelDefinition->serialise($format);
         
+        $returnValue = false;
         foreach ($data as $subjectUri => $propertiesValues){
             foreach ($propertiesValues as $prop=>$values){
                 foreach ($values as $k => $v) {
-                    $this->addStatement($modelId, $subjectUri, $prop, $v['value'], isset($v['lang']) ? $v['lang'] : null);
+                    $returnValue |= $this->addStatement($modelId, $subjectUri, $prop, $v['value'], $v['lang'] ?? null);
                 }
             }
         }
         
-        return true;
+        return $returnValue;
     }
     
     /**
      * Adds a statement to the ontology if it does not exist yet
      * 
      * @author "Joel Bout, <joel@taotesting.com>"
-     * @param int $modelId
+     * @param string|int $modelId
      * @param string $subject
      * @param string $predicate
      * @param string $object
      * @param string $lang
+     * @param string $author
+     * @return bool Was a row added?
      */
-    private function addStatement($modelId, $subject, $predicate, $object, $lang = null) {
-        $result = core_kernel_classes_DbWrapper::singleton()->query(
+    public function addStatement($modelId, $subject, $predicate, $object, $lang = null, $author = self::DEFAULT_AUTHOR) {
+        // Casting values and types.
+        $object = (string)$object;
+        if (is_null($lang)) {
+            $lang = '';
+        }
+        
+        // TODO: refactor this to use a triple store abstraction.
+        $result = $this->getPersistence()->query(
             'SELECT count(*) FROM statements WHERE modelid = ? AND subject = ? AND predicate = ? AND object = ? AND l_language = ?',
-            array($modelId, $subject, $predicate, $object, (is_null($lang)) ? '' : $lang)
+            array($modelId, $subject, $predicate, $object, $lang)
         );
         
-        if (intval($result->fetchColumn()) === 0) {
-            $dbWrapper = core_kernel_classes_DbWrapper::singleton();
-            $date = $dbWrapper->getPlatForm()->getNowExpression();
+        if ((int)$result->fetchColumn() > 0) {
+            return false;
+        }
+        
+        return (bool)$this->getPersistence()->insert(
+            'statements',
+            $this->prepareStatement($modelId, $subject, $predicate, $object, $lang, is_null($author) ? '' : $author)
+        );
+    }
+
+    /**
+     * Prepares a statement to be inserted in the ontology.
+     * @param string|int $modelId
+     * @param string     $subject
+     * @param string     $predicate
+     * @param string     $object
+     * @param string     $lang
+     * @param string     $author
+     * @return array
+     */
+    abstract public function prepareStatement($modelId, $subject, $predicate, $object, $lang, $author);
 
-            $dbWrapper->insert(
-                'statements',
-                array(
-                    'modelid' =>  $modelId,
-                    'subject' =>$subject,
-                    'predicate'=> $predicate,
-                    'object' => $object,
-                    'l_language' => is_null($lang) ? '' : $lang,
-                    'author' => 'http://www.tao.lu/Ontologies/TAO.rdf#installator',
-                    'epoch' => $date
-                )
-            );
+    /**
+     * Creates a query for iterator on selected statements.
+     * @param $modelIds
+     * @return string
+     */
+    public function getIteratorQuery($modelIds)
+    {
+        $where = '';
+        if ($modelIds !== null) {
+            $where = 'WHERE ' . $this->buildModelSqlCondition($modelIds);
         }
+        return sprintf('SELECT * FROM statements %s ORDER BY %s', $where, $this->getPropertySortingField());
     }
     
-
-}
\ No newline at end of file
+    /**
+     * Prepares parameters for statement selection.
+     * @param array $models
+     *
+     * @return string
+     */
+    public function buildModelSqlCondition(array $models)
+    {
+        return 'modelid IN (' . implode(',', $models) . ')';
+    }
+    
+    /**
+     * Returns the property to sort the statements on.
+     * @return string
+     */
+    abstract public function getPropertySortingField();
+    /**
+     * Creates table schema for models.
+     *
+     * @param Schema $schema
+     *
+     * @return Table
+     */
+    abstract public function createModelsTable(Schema $schema);
+    /**
+     * Creates table schema for statements.
+     *
+     * @param Schema $schema
+     *
+     * @return Table
+     */
+    abstract public function createStatementsTable(Schema $schema);
+    /**
+     * @return Persistence
+     */
+    public function getPersistence()
+    {
+        $persistenceId = $this->hasOption(self::OPTION_PERSISTENCE) ?
+            $this->getOption(self::OPTION_PERSISTENCE)
+            : 'default';
+        return $this->getServiceLocator()->get(PersistenceManager::SERVICE_ID)->getPersistenceById($persistenceId);
+    }
+}
diff --git a/core/kernel/impl/class.ApiModelOO.php b/core/kernel/impl/class.ApiModelOO.php
index 21996e8e8..ed913c023 100644
--- a/core/kernel/impl/class.ApiModelOO.php
+++ b/core/kernel/impl/class.ApiModelOO.php
@@ -22,9 +22,13 @@
 ?>
 <?php
 
+use core_kernel_api_ModelFactory as ModelFactory;
+use core_kernel_classes_DbWrapper as DbWrapper;
+use core_kernel_persistence_Exception as PersistenceException;
 use oat\generis\model\OntologyRdf;
 use oat\generis\model\OntologyRdfs;
-use Doctrine\DBAL\DBALException;
+use oat\oatbox\log\LoggerAwareTrait;
+use oat\oatbox\service\ServiceManager;
 
 error_reporting(E_ALL);
 
@@ -47,6 +51,8 @@ class core_kernel_impl_ApiModelOO
     extends core_kernel_impl_Api
         implements core_kernel_api_ApiModel
 {
+    use LoggerAwareTrait;
+
     // --- ASSOCIATIONS ---
 
 
@@ -56,9 +62,12 @@ class core_kernel_impl_ApiModelOO
      * Short description of attribute instance
      *
      * @access private
-     * @var ApiModelOO
+     * @var core_kernel_impl_ApiModelOO
      */
     private static $instance = null;
+    
+    /** @var ModelFactory */
+    private $modelFactory;
 
     // --- OPERATIONS ---
 
@@ -81,7 +90,7 @@ public function exportXmlRdf($sourceNamespaces = array())
 				$namespace .= "#";
 			}
 
-			$result = $dbWrapper->query('SELECT * FROM "models"  WHERE "modeluri" = ?', array(
+			$result = $this->getPersistence()->query('SELECT * FROM "models"  WHERE "modeluri" = ?', array(
 				$namespace
 			));
 			if ($row = $result->fetch(PDO::FETCH_ASSOC)){
@@ -104,8 +113,6 @@ public function exportXmlRdf($sourceNamespaces = array())
      */
     public function importXmlRdf($targetNameSpace, $fileLocation)
     {
-        $returnValue = (bool) false;
-
         if(!file_exists($fileLocation) || !is_readable($fileLocation)){
             throw new common_Exception("Unable to load ontology : $fileLocation");
         }
@@ -113,12 +120,7 @@ public function importXmlRdf($targetNameSpace, $fileLocation)
 	    if(!preg_match("/#$/", $targetNameSpace)){
 			$targetNameSpace .= '#';
 		}
-		$modFactory = new core_kernel_api_ModelFactory();
-		$returnValue = $modFactory->createModel($targetNameSpace, file_get_contents($fileLocation));
-		
-
-
-        return (bool) $returnValue;
+        return $this->modelFactory->createModel($targetNameSpace, file_get_contents($fileLocation));
     }
 
 
@@ -134,14 +136,11 @@ public function importXmlRdf($targetNameSpace, $fileLocation)
      */
     public function getResourceDescriptionXML($uriResource)
     {
-        $returnValue = (string) '';
+        $returnValue = '';
 
         
-        
-        
-        
-    	$dbWrapper = core_kernel_classes_DbWrapper::singleton();
-		$subject = $dbWrapper->quote($uriResource);
+        $persistence = $this->getPersistence();
+		$subject = $persistence->quote($uriResource);
 		
 		$baseNs = array(
 						'xmlns:rdf'		=> 'http://www.w3.org/1999/02/22-rdf-syntax-ns#',
@@ -150,8 +149,8 @@ public function getResourceDescriptionXML($uriResource)
 		
 		$query = 'SELECT "models"."modelid", "models"."modeluri" FROM "models" INNER JOIN "statements" ON "statements"."modelid" = "models"."modelid"
 											WHERE "statements"."subject" = ' . $subject;
-		$query = $dbWrapper->limitStatement($query, 1);
-		$result = $dbWrapper->query($query);
+		$query = $persistence->limitStatement($query, 1);
+		$result = $persistence->query($query);
 		if($row = $result->fetch()){
 			$modelId  = $row['modelid'];
 			$modelUri =  $row['modeluri'];
@@ -166,7 +165,7 @@ public function getResourceDescriptionXML($uriResource)
 		
 		
 		$allModels = array();
-		$result = $dbWrapper->query('SELECT * FROM "models"');
+		$result = $persistence->query('SELECT * FROM "models"');
 		while($row = $result->fetch(PDO::FETCH_ASSOC)){
 			$allModels[] = $row;
 		}
@@ -194,7 +193,7 @@ public function getResourceDescriptionXML($uriResource)
 			$description = $dom->createElement('rdf:Description');
 			$description->setAttribute('rdf:about', $uriResource);
 			
-			$result = $dbWrapper->query('SELECT * FROM "statements" WHERE "subject" = ' . $subject);
+			$result = $persistence->query('SELECT * FROM "statements" WHERE "subject" = ' . $subject);
 			while($row = $result->fetch()){
 				
 				$predicate 	= trim($row['predicate']);
@@ -252,7 +251,7 @@ public function getResourceDescriptionXML($uriResource)
 						$description->appendChild($node);
 					}
 					catch(DOMException $de){
-						//print $de;
+                        $this->logError($de);
 					}
 				}
 			}
@@ -260,13 +259,13 @@ public function getResourceDescriptionXML($uriResource)
 			$returnValue = $dom->saveXml();
 		}
 		catch(DomException $e){
-			print $e;
+			$this->logError($e);
 		}
         
         
         
 
-        return (string) $returnValue;
+        return $returnValue;
     }
 
     /**
@@ -278,9 +277,6 @@ public function getResourceDescriptionXML($uriResource)
      */
     public function getMetaClasses()
     {
-        $returnValue = null;
-
-        
         $returnValue = new core_kernel_classes_ContainerCollection(new core_kernel_classes_Container(__METHOD__),__METHOD__);
         
         $classClass = new core_kernel_classes_Class(OntologyRdfs::RDFS_CLASS);
@@ -301,17 +297,11 @@ public function getMetaClasses()
      */
     public function getRootClasses()
     {
-        $returnValue = null;
-
-        
-    
         $returnValue = new core_kernel_classes_ContainerCollection(new core_kernel_classes_Container(__METHOD__),__METHOD__);
         
-        $dbWrapper = core_kernel_classes_DbWrapper::singleton();
-        
         $query =  "SELECT DISTINCT subject FROM statements WHERE (predicate = ? AND object = ?) 
         			AND subject NOT IN (SELECT subject FROM statements WHERE predicate = ?)";
-    	$result	= $dbWrapper->query($query, array(
+    	$result	= $this->getPersistence()->query($query, array(
 			OntologyRdf::RDF_TYPE,
             OntologyRdfs::RDFS_CLASS,
             OntologyRdfs::RDFS_SUBCLASSOF
@@ -339,37 +329,16 @@ public function getRootClasses()
      */
     public function setStatement($subject, $predicate, $object, $language)
     {
-        $returnValue = (bool) false;
-
-        
-        $dbWrapper 	= core_kernel_classes_DbWrapper::singleton();
-        $platform   = $dbWrapper->getPlatForm();
-        $localNs 	= common_ext_NamespaceManager::singleton()->getLocalNamespace();
-        $mask		= 'yyy[admin,administrators,authors]';	//now it's the default right mode
-        $query = 'INSERT INTO statements (modelid,subject,predicate,object,l_language,author,epoch)
-        			VALUES  (?, ?, ?, ?, ?, ? , ?);';
-
-        try{
-	        $returnValue = $dbWrapper->exec($query, array(
-	       		$localNs->getModelId(),
-	       		$subject,
-	       		$predicate,
-	       		$object,
-	       		$language,
-	       		\common_session_SessionManager::getSession()->getUserUri(),
-	            $platform->getNowExpression()
-	             
-	        ));
-        }
-        catch (DBALException $e){
-	        if($e->getCode() !== '00000'){
-				throw new common_Exception ("Unable to setStatement (SPO) {$subject}, {$predicate}, {$object} : " . $e->getMessage());
-			}
-        }
-        
-        
-
-        return (bool) $returnValue;
+        $modelId = common_ext_NamespaceManager::singleton()->getLocalNamespace()->getModelId();
+        $currentUser = common_session_SessionManager::getSession()->getUserUri();
+        return $this->modelFactory->addStatement(
+            $modelId,
+            $subject,
+            $predicate,
+            $object,
+            $language,
+            $currentUser
+        );
     }
 
     /**
@@ -381,16 +350,10 @@ public function setStatement($subject, $predicate, $object, $language)
      */
     public function getAllClasses()
     {
-        $returnValue = null;
-
-        
-    	
         $returnValue = new core_kernel_classes_ContainerCollection(new core_kernel_classes_Container(__METHOD__),__METHOD__);
         
-        $dbWrapper = core_kernel_classes_DbWrapper::singleton();
-        
         $query =  "SELECT DISTINCT subject FROM statements WHERE (predicate = ? AND object = ?) OR predicate = ?";
-    	$result	= $dbWrapper->query($query, array(
+    	$result	= $this->getPersistence()->query($query, array(
 			OntologyRdf::RDF_TYPE,
             OntologyRdfs::RDFS_CLASS,
             OntologyRdfs::RDFS_SUBCLASSOF
@@ -416,17 +379,14 @@ public function getAllClasses()
      */
     public function getSubject($predicate, $object)
     {
-        $returnValue = null;
-
+        $returnValue = new core_kernel_classes_ContainerCollection(new common_Object(__METHOD__));
         
 		
 		$sqlQuery = "SELECT subject FROM statements WHERE predicate = ? AND object= ? ";
-		$dbWrapper = core_kernel_classes_DbWrapper::singleton();
-		$sqlResult = $dbWrapper->query($sqlQuery, array (
+		$sqlResult = $this->getPersistence()->query($sqlQuery, array (
 			$predicate,
 			$object
 		));
-		$returnValue = new core_kernel_classes_ContainerCollection(new common_Object(__METHOD__));
 		while ($row = $sqlResult->fetch()){
 			$container = new core_kernel_classes_Resource($row['subject'], __METHOD__);
 			$container->debug = __METHOD__ ;
@@ -451,16 +411,11 @@ public function getSubject($predicate, $object)
      */
     public function removeStatement($subject, $predicate, $object, $language)
     {
-        $returnValue = (bool) false;
-
-        
-        $dbWrapper 	= core_kernel_classes_DbWrapper::singleton();
-    
         $query = "DELETE FROM statements WHERE subject = ?
         			AND predicate = ? AND object = ?
         			AND (l_language = ? OR l_language = '')";
 
-        $returnValue = $dbWrapper->exec($query, array(
+        $returnValue = $this->getPersistence()->exec($query, array(
        		$subject,
        		$predicate,
        		$object,
@@ -483,16 +438,14 @@ public function removeStatement($subject, $predicate, $object, $language)
      */
     public function getObject($subject, $predicate)
     {
-        $returnValue = null;
-
+        $returnValue = new core_kernel_classes_ContainerCollection(new common_Object(__METHOD__));
         
     	$sqlQuery = "SELECT object FROM statements WHERE subject = ? AND predicate = ?";
-		$dbWrapper = core_kernel_classes_DbWrapper::singleton();
-		$sqlResult = $dbWrapper->query($sqlQuery, array (
+		$sqlResult = $this->getPersistence()->query($sqlQuery, array (
 			$subject,
 			$predicate
 		));
-		$returnValue = new core_kernel_classes_ContainerCollection(new common_Object(__METHOD__));
+		
 		while ($row = $sqlResult->fetch()){
 			
 			$value = $row['object'];
@@ -541,8 +494,17 @@ public static function singleton()
      */
     private function __construct()
     {
-        
-        
+        $serviceManager = ServiceManager::getServiceManager();
+        $this->modelFactory = $serviceManager->get(ModelFactory::SERVICE_ID);
     }
 
-}
\ No newline at end of file
+    /**
+     * @return DbWrapper
+     * @throws PersistenceException
+     */
+    public function getPersistence()
+    {
+        // @TODO: inject dbWrapper as a dependency.
+        return DbWrapper::singleton();
+    }
+}
diff --git a/core/kernel/persistence/smoothsql/class.Resource.php b/core/kernel/persistence/smoothsql/class.Resource.php
index 6e2c6695c..2d624073d 100644
--- a/core/kernel/persistence/smoothsql/class.Resource.php
+++ b/core/kernel/persistence/smoothsql/class.Resource.php
@@ -20,6 +20,7 @@
  *               2017 (update and modification) Open Assessment Technologies SA (under the project TAO-PRODUCT);
  */
 
+use core_kernel_api_ModelFactory as ModelFactory;
 use oat\generis\model\OntologyRdf;
 use oat\oatbox\session\SessionService;
 use oat\oatbox\user\UserLanguageServiceInterface;
@@ -36,19 +37,39 @@
 class core_kernel_persistence_smoothsql_Resource
     implements core_kernel_persistence_ResourceInterface
 {
+    /** @var ModelFactory */
+    protected $modelFactory;
 
     /**
      * @var core_kernel_persistence_smoothsql_SmoothModel
      */
     private $model;
     
+    /**
+     * core_kernel_persistence_smoothsql_Resource constructor.
+     *
+     * @param core_kernel_persistence_smoothsql_SmoothModel $model
+     */
     public function __construct(core_kernel_persistence_smoothsql_SmoothModel $model) {
         $this->model = $model;
     }
     
+    /**
+     * @return core_kernel_persistence_smoothsql_SmoothModel
+     */
     protected function getModel() {
         return $this->model;
     }
+
+    /**
+     * @return ModelFactory
+     */
+    protected function getModelFactory() {
+        if ($this->modelFactory === null) {
+            $this->modelFactory = $this->getServiceLocator()->get(ModelFactory::SERVICE_ID);
+        }
+        return $this->modelFactory;
+    }
     
     /**
      * @return common_persistence_SqlPersistence
@@ -58,11 +79,11 @@ protected function getPersistence() {
     }
     
     protected function getModelReadSqlCondition() {
-        return 'modelid IN ('.implode(',', $this->model->getReadableModels()).')';
+        return $this->getModelFactory()->buildModelSqlCondition($this->model->getReadableModels());
     }
     
     protected function getModelWriteSqlCondition() {
-        return 'modelid IN ('.implode(',',$this->model->getWritableModels()).')';
+        return $this->getModelFactory()->buildModelSqlCondition($this->model->getWritableModels());
     }
     
     protected function getNewTripleModelId() {
@@ -105,6 +126,7 @@ public function getTypes( core_kernel_classes_Resource $resource)
      * @param  Property property
      * @param  array options
      * @return array
+     * @throws core_kernel_persistence_Exception
      */
     public function getPropertyValues( core_kernel_classes_Resource $resource,  core_kernel_classes_Property $property, $options = array())
     {
@@ -118,7 +140,6 @@ public function getPropertyValues( core_kernel_classes_Resource $resource,  core
 		$platform = $this->getPersistence()->getPlatForm();
 		
     	// Define language if required
-		$lang = '';
 		$defaultLg = '';
 		if (isset($options['lg'])) {
 			$lang = $options['lg'];
@@ -137,14 +158,11 @@ public function getPropertyValues( core_kernel_classes_Resource $resource,  core
         
     	
 		if ($one) {
-            // Select first
-			$query .= ' ORDER BY id DESC';
+            // Select first only
+			$query .= ' ORDER BY ' . $this->getModelFactory()->getPropertySortingField() . ' DESC';
 			$query = $platform->limitStatement($query, 1, 0);
-			$result = $this->getPersistence()->query($query,array($resource->getUri(), $property->getUri(), $lang));
-		} else {
-            // Select All
-			$result = $this->getPersistence()->query($query,array($resource->getUri(), $property->getUri(), $lang));
 		}
+        $result = $this->getPersistence()->query($query,array($resource->getUri(), $property->getUri(), $lang));
         
 		// Treat the query result
         if ($result == true) {
@@ -207,33 +225,21 @@ public function setPropertyValue( core_kernel_classes_Resource $resource,  core_
     {
         $userId = $this->getServiceLocator()->get(SessionService::SERVICE_ID)->getCurrentUser()->getIdentifier();
         $object  = $object instanceof core_kernel_classes_Resource ? $object->getUri() : (string) $object;
-    	$platform = $this->getPersistence()->getPlatForm();
-        $lang = "";
+
         // Define language if required
+        $lang = '';
         if ($property->isLgDependent()){
-        	if ($lg!=null){
-        		$lang = $lg;
-        	} else {
-                $lang = $this->getServiceLocator()->get(SessionService::SERVICE_ID)->getCurrentSession()->getDataLanguage();
-        	}
+      		$lang = $lg ?? $this->getServiceLocator()->get(SessionService::SERVICE_ID)->getCurrentSession()->getDataLanguage();
         }
         
-        $query = 'INSERT INTO statements (modelid, subject, predicate, object, l_language, author,epoch)
-        			VALUES  (?, ?, ?, ?, ?, ? , ?)';
-
-        $returnValue = $this->getPersistence()->exec($query, array(
+        return $this->getModelFactory()->addStatement(
        		$this->getNewTripleModelId(),
        		$resource->getUri(),
        		$property->getUri(),
        		$object,
        		$lang,
-            $userId,
-            $platform->getNowExpression()
-        ));
-        
-        
-
-        return (bool) $returnValue;
+            $userId
+        );
     }
 
     /**
@@ -247,52 +253,54 @@ public function setPropertyValue( core_kernel_classes_Resource $resource,  core_
      */
     public function setPropertiesValues( core_kernel_classes_Resource $resource, $properties)
     {
-        $returnValue = (bool) false;
+        $returnValue = false;
 
     	if (is_array($properties) && count($properties) > 0) {
         		
             $session = $this->getServiceLocator()->get(SessionService::SERVICE_ID)->getCurrentSession();
-            $platform = $this->getPersistence()->getPlatForm();
 
-            $valuesToInsert = [];
+            $modelId = $this->getNewTripleModelId();
+            $subject = $resource->getUri();
+            $author = $session->getUser()->getIdentifier();
 
             foreach ($properties as $propertyUri => $value) {
                 
                 $property = $this->getModel()->getProperty($propertyUri);
                 
                 $lang = ($property->isLgDependent() ? $session->getDataLanguage() : '');
-                $formatedValues = [];
                 
-                if ($value instanceof core_kernel_classes_Resource) {
-                    $formatedValues[] = $value->getUri();
-                    
-                } elseif (is_array($value)) {
-                    foreach($value as $val){
-                        $formatedValues[] = ($val instanceof core_kernel_classes_Resource) ? $val->getUri() : $val;
-                    }
-                } else {
-                    $formatedValues[] = ($value == null) ? '' : $value;
-                }
+                $formattedValues = $this->formatValue($value);
                 
-                foreach ($formatedValues as $object) {
-                    $valuesToInsert[] = [
-                        'modelid' => $this->getNewTripleModelId(),
-                        'subject' => $resource->getUri(),
-                        'predicate' => $property->getUri(),
-                        'object' => $object,
-                        'l_language' => $lang,
-                        'author' => $session->getUser()->getIdentifier(),
-                        'epoch' => $platform->getNowExpression()
-                    ];
+                foreach ($formattedValues as $object) {
+                    $returnValue |= $this->getModelFactory()->addStatement($modelId, $subject, $property->getUri(), $object, $lang, $author);
                 }
             }
-
-            $returnValue = $this->getPersistence()->insertMultiple('statements', $valuesToInsert);
         }
         
-        return (bool) $returnValue;
+        return $returnValue;
     }
 
+    /**
+     * Formats single or multiple value
+     * @param mixed $value
+     * @return array
+     */
+    private function formatValue($value)
+    {
+        if (!is_array($value)) {
+            $value = [$value];
+        }
+
+        $formattedValues = [];
+        foreach ($value as $val) {
+            $formattedValues[] = $val instanceof core_kernel_classes_Resource 
+                ? $val->getUri() 
+                : ($val ?? '');
+        }
+        
+        return $formattedValues;
+    }
+    
     /**
      * Short description of method setPropertyValueByLg
      *
@@ -306,29 +314,16 @@ public function setPropertiesValues( core_kernel_classes_Resource $resource, $pr
      */
     public function setPropertyValueByLg( core_kernel_classes_Resource $resource,  core_kernel_classes_Property $property, $value, $lg)
     {
-        $returnValue = (bool) false;
-
-        
-
-		$platform = $this->getPersistence()->getPlatForm();
 		$userId = $this->getServiceLocator()->get(SessionService::SERVICE_ID)->getCurrentUser()->getIdentifier();
-        
-        $query = 'INSERT INTO statements (modelid,subject,predicate,object,l_language,author,epoch)
-        			VALUES  (?, ?, ?, ?, ?, ?, ?)';
-
-        $returnValue = $this->getPersistence()->exec($query, array(
-       		$this->getNewTripleModelId(),
-       		$resource->getUri(),
-       		$property->getUri(),
-       		$value,
-       		($property->isLgDependent() ? $lg : ''),
-       		$userId,
-            $platform->getNowExpression()
-        ));
-		
-        
 
-        return (bool) $returnValue;
+        return $this->getModelFactory()->addStatement(
+            $this->getNewTripleModelId(),
+            $resource->getUri(),
+            $property->getUri(),
+            $value,
+            ($property->isLgDependent() ? $lg : ''),
+            $userId
+        );
     }
 
     /**
@@ -343,8 +338,6 @@ public function setPropertyValueByLg( core_kernel_classes_Resource $resource,  c
      */
     public function removePropertyValues( core_kernel_classes_Resource $resource,  core_kernel_classes_Property $property, $options = array())
     {
-        $returnValue = (bool) false;
-
 		// Optional params
         $pattern = isset($options['pattern']) && !is_null($options['pattern']) ? $options['pattern'] : null;
         $like = isset($options['like']) && $options['like'] == true ? true : false;
@@ -415,25 +408,15 @@ public function removePropertyValues( core_kernel_classes_Resource $resource,  c
      */
     public function removePropertyValueByLg( core_kernel_classes_Resource $resource,  core_kernel_classes_Property $property, $lg, $options = array())
     {
-        $returnValue = (bool) false;
-
         $sqlQuery = 'DELETE FROM statements WHERE subject = ? and predicate = ? and l_language = ?';
         //be sure the property we try to remove is included in an updatable model
 		$sqlQuery .= ' AND '.$this->getModelWriteSqlCondition();
-        
-        $returnValue = $this->getPersistence()->exec($sqlQuery, array (
+
+        return (bool) $this->getPersistence()->exec($sqlQuery, array (
         	$resource->getUri(),
         	$property->getUri(),
             ($property->isLgDependent() ? $lg : '')
         ));
-        
-    	if (!$returnValue){
-        	$returnValue = false;
-        }
-        
-        
-
-        return (bool) $returnValue;
     }
 
     /**
@@ -507,39 +490,39 @@ public function getUsedLanguages( core_kernel_classes_Resource $resource,  core_
      * @param  Resource resource
      * @param  array excludedProperties
      * @return core_kernel_classes_Resource
+     * @throws common_exception_Error
      */
     public function duplicate( core_kernel_classes_Resource $resource, $excludedProperties = array())
     {
-        $returnValue = null;
-        $newUri = $this->getServiceLocator()->get(UriProvider::SERVICE_ID)->provide();
     	$collection = $this->getRdfTriples($resource);
         
-    	if ($collection->count() > 0) {
-    		
-    		$platform = $this->getPersistence()->getPlatForm();
-            $user = $this->getServiceLocator()->get(SessionService::SERVICE_ID)->getCurrentUser()->getIdentifier();
-            $valuesToInsert = [];
+    	if ($collection->count() === 0) {
+            return null;
+        }
+
+        $newUri = $this->getServiceLocator()->get(UriProvider::SERVICE_ID)->provide();
+        $user = $this->getServiceLocator()->get(SessionService::SERVICE_ID)->getCurrentUser()->getIdentifier();
+        $modelId = $this->getNewTripleModelId();
+        $addedRows = false;
     		
-    		foreach ($collection->getIterator() as $triple) {
-    			if (!in_array($triple->predicate, $excludedProperties)) {
-                    $valuesToInsert[] = [
-                        'modelid' => $this->getNewTripleModelId(),
-                        'subject' => $newUri,
-                        'predicate'=> $triple->predicate,
-                        'object' => ($triple->object == null) ? '' : $triple->object,
-                        'l_language' => ($triple->lg == null) ? '' : $triple->lg,
-                        'author' => $user,
-                        'epoch' => $platform->getNowExpression()
-                    ];
-    			}
-	    	}
-	    	
-        	if ($this->getPersistence()->insertMultiple('statements', $valuesToInsert)) {
-                $returnValue = $this->getModel()->getResource($newUri);
-        	}
-    	}
+        foreach ($collection->getIterator() as $triple) {
+            if (!in_array($triple->predicate, $excludedProperties)) {
+                $addedRows |= $this->getModelFactory()->addStatement(
+                    $modelId,
+                    $newUri,
+                    $triple->predicate,
+                    $triple->object ?? '',
+                    $triple->lg ?? '',
+                    $user
+                );
+            }
+        }
         
-        return $returnValue;
+        if ($addedRows) {
+            return $this->getModel()->getResource($newUri);
+        }
+    	        
+        return null;
     }
 
     /**
@@ -553,8 +536,6 @@ public function duplicate( core_kernel_classes_Resource $resource, $excludedProp
      */
     public function delete( core_kernel_classes_Resource $resource, $deleteReference = false)
     {
-        $returnValue = (bool) false;
-
 		$query = 'DELETE FROM statements WHERE subject = ? AND '.$this->getModelWriteSqlCondition();
         $returnValue = $this->getPersistence()->exec($query, array($resource->getUri()));
 
@@ -662,10 +643,6 @@ public function setType( core_kernel_classes_Resource $resource,  core_kernel_cl
      */
     public function removeType( core_kernel_classes_Resource $resource,  core_kernel_classes_Class $class)
     {
-        $returnValue = (bool) false;
-
-        
-        
         $query =  'DELETE FROM statements 
 		    		WHERE subject = ? AND predicate = ? AND '. $this->getPersistence()->getPlatForm()->getObjectTypeCondition() .' = ?';
         
diff --git a/core/kernel/persistence/smoothsql/class.SmoothIterator.php b/core/kernel/persistence/smoothsql/class.SmoothIterator.php
index 872e44146..d0a641e26 100644
--- a/core/kernel/persistence/smoothsql/class.SmoothIterator.php
+++ b/core/kernel/persistence/smoothsql/class.SmoothIterator.php
@@ -18,6 +18,9 @@
  *
  */
 
+use core_kernel_api_ModelFactory as ModelFactory;
+use Zend\ServiceManager\ServiceLocatorAwareTrait;
+
 /**
  * Iterator over all triples
  * 
@@ -27,16 +30,18 @@
 class core_kernel_persistence_smoothsql_SmoothIterator
     extends common_persistence_sql_QueryIterator
 {
+    use ServiceLocatorAwareTrait;
+    
     /**
      * Constructor of the iterator expecting the model ids
      * 
+     * @param common_persistence_SqlPersistence $persistence
      * @param array $modelIds
      */
     public function __construct(common_persistence_SqlPersistence $persistence, $modelIds = null) {
-        $query = 'SELECT * FROM statements '
-            .(is_null($modelIds) ? '' : 'WHERE modelid IN ('.implode(',', $modelIds).') ')
-            .'ORDER BY id';
-        parent::__construct($persistence, $query);
+        /** @var ModelFactory $modelFactory */
+        $modelFactory = $this->getServiceLocator()->get(ModelFactory::SERVICE_ID);
+        parent::__construct($persistence, $modelFactory->getIteratorQuery($modelIds));
     }
     
     /**
@@ -46,7 +51,8 @@ public function __construct(common_persistence_SqlPersistence $persistence, $mod
      */
     function current() {
         $statement = parent::current();
-        
+
+        // TODO: create a constructor
         $triple = new core_kernel_classes_Triple();
         $triple->modelid = $statement["modelid"];
         $triple->subject = $statement["subject"];
@@ -57,4 +63,4 @@ function current() {
         $triple->author = $statement["author"];
         return $triple;
     }
-}
\ No newline at end of file
+}
diff --git a/core/kernel/persistence/smoothsql/class.SmoothRdf.php b/core/kernel/persistence/smoothsql/class.SmoothRdf.php
index 8baa34e07..ef5147200 100644
--- a/core/kernel/persistence/smoothsql/class.SmoothRdf.php
+++ b/core/kernel/persistence/smoothsql/class.SmoothRdf.php
@@ -18,6 +18,7 @@
  *
  */
 
+use core_kernel_api_ModelFactory as ModelFactory;
 use oat\generis\model\data\RdfInterface;
 use oat\generis\model\OntologyRdf;
 use oat\generis\model\OntologyRdfs;
@@ -63,8 +64,18 @@ public function add(\core_kernel_classes_Triple $triple) {
         if (!in_array($triple->modelid, $this->model->getReadableModels())) {
             $this->model->addReadableModel($triple->modelid);
         }
-        $query = "INSERT INTO statements ( modelId, subject, predicate, object, l_language, epoch, author) VALUES ( ? , ? , ? , ? , ? , ?, ?);";
-        $success = $this->getPersistence()->exec($query, array($triple->modelid, $triple->subject, $triple->predicate, $triple->object, is_null($triple->lg) ? '' : $triple->lg, $this->getPersistence()->getPlatForm()->getNowExpression(), is_null($triple->author) ? '' : $triple->author));
+        
+        /** @var ModelFactory $modelFactory */
+        $modelFactory = $this->getServiceManager()->get(ModelFactory::SERVICE_ID);
+        $success = $modelFactory->addStatement(
+            $triple->modelid, 
+            $triple->subject, 
+            $triple->predicate, 
+            $triple->object, 
+            $triple->lg ?? '', 
+            $triple->author ?? ''
+        );
+
         if ($triple->predicate == OntologyRdfs::RDFS_SUBCLASSOF || $triple->predicate == OntologyRdf::RDF_TYPE) {
             $eventManager = $this->getServiceManager()->get(EventManager::CONFIG_ID);
             $eventManager->trigger(new ResourceCreated(new core_kernel_classes_Resource($triple->subject)));
@@ -97,4 +108,4 @@ public function getServiceManager()
     {
         return ServiceManager::getServiceManager();
     }
-}
\ No newline at end of file
+}
diff --git a/core/kernel/persistence/smoothsql/install/SmoothRdsModel.php b/core/kernel/persistence/smoothsql/install/SmoothRdsModel.php
index ba3951414..6d051254f 100644
--- a/core/kernel/persistence/smoothsql/install/SmoothRdsModel.php
+++ b/core/kernel/persistence/smoothsql/install/SmoothRdsModel.php
@@ -19,40 +19,26 @@
  */
 namespace   oat\generis\model\kernel\persistence\smoothsql\install;
 
+use core_kernel_api_ModelFactory as ModelFactory;
 use Doctrine\DBAL\Schema\Schema;
+use oat\oatbox\service\ConfigurableService;
+
 /**
  * Helper to setup the required tables for generis smoothsql
  */
-class SmoothRdsModel {
-
+class SmoothRdsModel extends ConfigurableService
+{
     /**
      * 
      * @param Schema $schema
      * @return \Doctrine\DBAL\Schema\Schema
      */
-    public static function addSmoothTables(Schema $schema)
+    public function addSmoothTables(Schema $schema)
     {
-        $table = $schema->createTable("models");
-        $table->addColumn('modelid', "integer",["notnull" => true,"autoincrement" => true]);
-        $table->addColumn('modeluri', "string", ["length" => 255,"default" => null]);
-        $table->addOption('engine' , 'MyISAM');
-        $table->setPrimaryKey(['modelid']);
-
-        $table = $schema->createTable("statements");
-        $table->addColumn("modelid", "integer",["notnull" => true,"default" => 0]);
-        $table->addColumn("subject", "string",["length" => 255,"default" => null]);
-        $table->addColumn("predicate", "string",["length" => 255,"default" => null]);
-        $table->addColumn("object", "text", ["default" => null,"notnull" => false]);
-            
-        $table->addColumn("l_language", "string",["length" => 255,"default" => null,"notnull" => false]);
-        $table->addColumn("id", "integer",["notnull" => true,"autoincrement" => true]);
-        $table->addColumn("author", "string",["length" => 255,"default" => null,"notnull" => false]);
-        $table->setPrimaryKey(["id"]);
-        $table->addOption('engine' , 'MyISAM');
-        $table->addColumn("epoch", "string" , ["notnull" => null]);
-
-        $table->addIndex(["subject","predicate"],"k_sp", [], ['lengths' => [164,164]]);
-        $table->addIndex(["predicate","object"],"k_po", [], ['lengths' => [164,164]]);
+        /** @var ModelFactory $modelFactory */
+        $modelFactory = $this->getServiceLocator()->get(ModelFactory::SERVICE_ID);
+        $modelFactory->createModelsTable($schema);
+        $modelFactory->createStatementsTable($schema);
         return $schema;
     }
 }
diff --git a/test/GenerisTestCase.php b/test/GenerisTestCase.php
index a8d2353ce..3f6e5659b 100755
--- a/test/GenerisTestCase.php
+++ b/test/GenerisTestCase.php
@@ -19,6 +19,8 @@
  */
 namespace oat\generis\test;
 
+use core_kernel_api_ModelFactory as ModelFactory;
+use oat\generis\model\kernel\api\RdsModelFactory;
 use oat\generis\model\kernel\persistence\smoothsql\install\SmoothRdsModel;
 use oat\oatbox\user\UserLanguageServiceInterface;
 use oat\oatbox\session\SessionService;
@@ -39,14 +41,11 @@ class GenerisTestCase extends TestCase
      */
     protected function getOntologyMock()
     {
+        $smoothRdsModel = new SmoothRdsModel();
         $pm = $this->getSqlMock('mockSql');
         $rds = $pm->getPersistenceById('mockSql');
         $schema = $rds->getSchemaManager()->createSchema();
-        $schema = SmoothRdsModel::addSmoothTables($schema);
-        $queries = $rds->getPlatform()->schemaToSql($schema);
-        foreach ($queries as $query){
-            $rds->query($query);
-        }
+        $schema = $smoothRdsModel->addSmoothTables($schema);
         
         $session = new \common_session_AnonymousSession();
         $sl = $this->getServiceLocatorMock([
@@ -56,6 +55,7 @@ protected function getOntologyMock()
             EventManager::SERVICE_ID => new EventManager(),
             LoggerService::SERVICE_ID => $this->prophesize(LoggerInterface::class)->reveal(),
             UriProvider::SERVICE_ID => new Bin2HexUriProvider([Bin2HexUriProvider::OPTION_NAMESPACE => 'http://ontology.mock/bin2hex#']),
+            ModelFactory::SERVICE_ID => new RdsModelFactory(),
             'smoothcache' => new \common_cache_NoCache()
         ]);
         $session->setServiceLocator($sl);
@@ -67,7 +67,13 @@ protected function getOntologyMock()
             'cache' => 'smoothcache'
         ]);
         $model->setServiceLocator($sl);
-
+        $smoothRdsModel->setServiceLocator($sl);
+        $schema = $smoothRdsModel->addSmoothTables($schema);
+        $queries = $rds->getPlatform()->schemaToSql($schema);
+        foreach ($queries as $query){
+            $rds->query($query);
+        }
+        
         return $model;
     }