diff --git a/src/Attribute/Property/ArrayOf.php b/src/Attribute/Property/ArrayOf.php
index 3e4446f..56cf861 100644
--- a/src/Attribute/Property/ArrayOf.php
+++ b/src/Attribute/Property/ArrayOf.php
@@ -25,22 +25,26 @@ class ArrayOf implements \Ulmus\Entity\EntityValueModifier
                             sprintf("Given item '%s' is not a valid enum for type %s ; try one of theses instead : %s", $item, $this->type, implode("', '", array_map(fn($e) => $e->value, $this->type::cases())))
                         );
                     } else {
-                        $value = $this->type::from($item);
+                        $obj = $this->type::from($item);
                     }
                 }
                 elseif (class_exists($this->type)) {
                     if (is_subclass_of($this->type, JsonUnserializable::class)) {
-                        $value = (new \ReflectionClass($this->type))->newInstanceWithoutConstructor();
-                        $value->jsonUnserialize($item);
+                        $obj = (new \ReflectionClass($this->type))->newInstanceWithoutConstructor();
+                        $obj->jsonUnserialize($item);
                     }
                     else {
-                        $value = new $this->type($item);
+                        $obj = new $this->type($item);
                     }
                 }
+                else {
+                    throw new \InvalidArgumentException("Given type for ArrayOf is incompatible with it's use. An object should be provided");
+                }
 
-                $return[$index] = $value;
+                $return[$index] = $obj;
             }
         }
+
         if (! $property->type->builtIn) {
             $cls = $property->type->type;
 
diff --git a/src/Entity/ArrayCollection.php b/src/Entity/ArrayCollection.php
index b2ee592..c57e19b 100644
--- a/src/Entity/ArrayCollection.php
+++ b/src/Entity/ArrayCollection.php
@@ -6,7 +6,6 @@ use Ulmus\EntityCollection;
 
 class ArrayCollection extends EntityCollection implements JsonUnserializable
 {
-
     public function jsonUnserialize(array $json): void
     {
         $this->fromArray($json);
diff --git a/src/Entity/DatasetHandler.php b/src/Entity/DatasetHandler.php
index 0faba5f..b7a5639 100644
--- a/src/Entity/DatasetHandler.php
+++ b/src/Entity/DatasetHandler.php
@@ -17,7 +17,7 @@ class DatasetHandler
         protected bool $entityStrictFieldsDeclaration = false,
     ) {}
 
-    public function pull(object $entity) : Generator
+    public function pull(object $entity, bool $nullable = true) : Generator
     {
         foreach($this->entityResolver->fieldList(EntityResolver::KEY_ENTITY_NAME, true) as $key => $field) {
             $attribute = $this->entityResolver->searchFieldAnnotation($key,[ Field::class ]);
@@ -25,7 +25,7 @@ class DatasetHandler
             if ( $entity->__isset($key) ) {
                 yield $attribute->name ?? $key => $entity->$key;
             }
-            elseif ( $field->allowsNull() ) {
+            elseif ( $nullable && $field->allowsNull() ) {
                 yield $attribute->name ?? $key => null;
             }
         }
diff --git a/src/Entity/EntityInterface.php b/src/Entity/EntityInterface.php
index 3835a0e..9134a5b 100644
--- a/src/Entity/EntityInterface.php
+++ b/src/Entity/EntityInterface.php
@@ -18,7 +18,7 @@ interface EntityInterface extends SearchableInterface /* extends \JsonSerializab
     public function isLoaded() : bool;
     public function jsonSerialize() : mixed;
     public static function resolveEntity() : EntityResolver;
-    public static function repository(string $alias = Repository::DEFAULT_ALIAS, ConnectionAdapter $adapter = null) : Repository;
+    public static function repository(string $alias = Repository::DEFAULT_ALIAS, ?ConnectionAdapter $adapter = null) : Repository;
     public static function entityCollection(...$arguments) : EntityCollection;
     public static function queryBuilder() : QueryBuilderInterface;
     public static function field($name, null|string|false $alias = Repository::DEFAULT_ALIAS) : EntityField;
diff --git a/src/Entity/Field/Datetime.php b/src/Entity/Field/Datetime.php
index 3cf5662..37d31f4 100644
--- a/src/Entity/Field/Datetime.php
+++ b/src/Entity/Field/Datetime.php
@@ -28,7 +28,7 @@ class Datetime extends \DateTime implements EntityObjectInterface, \JsonSerializ
         return $obj;
     }
 
-    public function setTime($hour, $minute, $second = 0, $microsecond = 0) : \DateTimeInterface
+    public function setTime($hour, $minute, $second = 0, $microsecond = 0) : \DateTime
     {
         $fromParent = parent::setTime($hour, $minute, $second, $microsecond);
 
@@ -45,14 +45,15 @@ class Datetime extends \DateTime implements EntityObjectInterface, \JsonSerializ
         return $this->format($this->format);
     }
 
+    #[\Deprecated]
     public function formatLocale(string $format) : string
     {
         return strftime($format, $this->getTimestamp());
     }
 
-    public function formatLocaleIntl(int $dateFormatter = \IntlDateFormatter::LONG, int $timeFormatter = \IntlDateFormatter::NONE) : string
+    public function formatLocaleIntl(int $dateFormatter = \IntlDateFormatter::LONG, int $timeFormatter = \IntlDateFormatter::NONE, ? string $pattern = null) : string
     {
-        $formatter = new \IntlDateFormatter(\Locale::getDefault(), $dateFormatter, $timeFormatter, \Locale::getRegion(""));
+        $formatter = new \IntlDateFormatter(\Locale::getDefault(), $dateFormatter, $timeFormatter, \date_default_timezone_get(), \IntlDateFormatter::GREGORIAN, $pattern);
 
         return $formatter->format($this->getTimestamp());
     }
diff --git a/src/EntityTrait.php b/src/EntityTrait.php
index 491c46e..bbd2c5b 100644
--- a/src/EntityTrait.php
+++ b/src/EntityTrait.php
@@ -4,20 +4,15 @@ namespace Ulmus;
 
 use Notes\Attribute\Ignore;
 
-use Psr\Http\Message\ServerRequestInterface;
-
 use Ulmus\{Attribute\Obj\JsonSerialize,
-    Attribute\Property\Join,
-    Attribute\Property\Relation,
     Attribute\Property\ResettablePropertyInterface,
-    Attribute\Property\Virtual,
     Common\EntityResolver,
     Common\EntityField,
     Entity\DatasetHandler,
     Entity\EntityInterface,
     QueryBuilder\QueryBuilderInterface};
 
-use Ulmus\{Attribute\RegisterEntityEventInterface, Entity\EntityValueModifier, SearchRequest, Event};
+use Ulmus\{Attribute\RegisterEntityEventInterface, Entity\EntityValueModifier, };
 
 #[JsonSerialize(includeRelations: true)]
 trait EntityTrait {
@@ -33,7 +28,7 @@ trait EntityTrait {
     protected array $entityDatasetUnmatchedFields = [];
 
     #[Ignore]
-    protected DatasetHandler $datasetHandler;
+    public DatasetHandler $datasetHandler;
 
     #[Ignore]
     public string $loadedFromAdapter;
@@ -82,7 +77,16 @@ trait EntityTrait {
         foreach($generator as $field => $value) {
             foreach($properties[$field]->attributes as $tag) {
                 if ( $tag->object instanceof EntityValueModifier ) {
-                    $value = $tag->object->push($value, $properties[$field]);
+                    try {
+                        $value = $tag->object->push($value, $properties[$field]);
+                    }
+                    catch(\Throwable $ex) {
+                        throw new \LogicException(
+                            message: sprintf("An error occured trying to push an EntityValueModifier results : %s", $ex->getMessage()),
+                            code: $ex->getCode(),
+                            previous: $ex,
+                        );
+                    }
                 }
             }
 
@@ -128,6 +132,18 @@ trait EntityTrait {
         }
     }
 
+    #[Ignore]
+    public function entityGetDiffDataset() : array
+    {
+        $return = [];
+
+        foreach($this->datasetHandler->pull($this, false) as $field => $value) {
+             $return[$field] = static::repository()->adapter->adapter()->writableValue($value);
+        }
+
+        return $return;
+    }
+
     #[Ignore]
     public function resetVirtualProperties() : self
     {
@@ -217,7 +233,12 @@ trait EntityTrait {
             return true;
         }
 
-        return isset($this->$name);
+        if (isset($this->$name)) {
+            return true;
+        }
+
+        # Handling undefined 'nullable'
+        return new \ReflectionProperty($this, $name)->isInitialized($this);
     }
 
     #[Ignore]
@@ -289,7 +310,7 @@ trait EntityTrait {
     }
 
     #[Ignore]
-    public static function repository(string $alias = Repository::DEFAULT_ALIAS, ConnectionAdapter $adapter = null) : Repository
+    public static function repository(string $alias = Repository::DEFAULT_ALIAS, ?ConnectionAdapter $adapter = null) : Repository
     {
         return Ulmus::repository(static::class, $alias, $adapter);
     }
diff --git a/src/QueryBuilder/Sql/MysqlQueryBuilder.php b/src/QueryBuilder/Sql/MysqlQueryBuilder.php
index 658a2d1..a1c1043 100644
--- a/src/QueryBuilder/Sql/MysqlQueryBuilder.php
+++ b/src/QueryBuilder/Sql/MysqlQueryBuilder.php
@@ -491,7 +491,7 @@ class MysqlQueryBuilder extends SqlQueryBuilder
         }
     }
 
-    public function getFragments(QueryFragmentInterface|array|\Stringable|string $fragment = null) : array
+    public function getFragments(QueryFragmentInterface|array|\Stringable|string|null $fragment = null) : array
     {
         return $fragment !== null ? array_filter($this->queryStack, fn($e) => is_a($e, $fragment, true) ) : $this->queryStack;
     }
@@ -501,7 +501,7 @@ class MysqlQueryBuilder extends SqlQueryBuilder
         return $this->render();
     }
 
-    public function addParameter(mixed $value, string $key = null) : string
+    public function addParameter(mixed $value, ?string $key = null) : string
     {
         if ( $this->parent ?? false ) {
             return $this->parent->addParameter($value, $key);
@@ -540,4 +540,5 @@ class MysqlQueryBuilder extends SqlQueryBuilder
 
         return $next + 1;
     }
+
 }
diff --git a/src/Repository.php b/src/Repository.php
index 420de9e..4d20fc7 100644
--- a/src/Repository.php
+++ b/src/Repository.php
@@ -337,7 +337,7 @@ class Repository implements RepositoryInterface
 
     public function generateDatasetDiff(object $entity, bool $oldValues = false) : array
     {
-        $array = array_change_key_case($entity->toArray());
+        $array = array_change_key_case($entity->entityGetDiffDataset());
 
         $dataset = array_change_key_case($entity->entityGetDataset(false, true));
 
diff --git a/src/Ulmus.php b/src/Ulmus.php
index 675c101..09d8848 100644
--- a/src/Ulmus.php
+++ b/src/Ulmus.php
@@ -108,7 +108,7 @@ abstract class Ulmus
         return static::$resolved[$entityClass] ?? static::$resolved[$entityClass] = new Common\EntityResolver($entityClass, static::$cache);
     }
 
-    public static function repository(string $entityClass, string $alias = Repository::DEFAULT_ALIAS, ConnectionAdapter $adapter = null) : Repository
+    public static function repository(string $entityClass, string $alias = Repository::DEFAULT_ALIAS, ?ConnectionAdapter $adapter = null) : Repository
     {
         $adapter ??= $entityClass::resolveEntity()->sqlAdapter();
         $cls = $adapter->adapter()->repositoryClass();