diff --git a/Core/API/Parameter/Parameter.class.php b/Core/API/Parameter/Parameter.class.php
index 70843b6..7ea8ef1 100644
--- a/Core/API/Parameter/Parameter.class.php
+++ b/Core/API/Parameter/Parameter.class.php
@@ -77,7 +77,12 @@ class Parameter {
   public function getTypeName(): string {
     $typeName = Parameter::names[$this->type] ?? "INVALID";
     if ($this->choices) {
-      $typeName .= ", choices: " . json_encode($this->choices);
+      $typeName .= ", choices=" . json_encode($this->choices);
+    }
+
+    $format = $this->getSwaggerFormat();
+    if ($format && $this->type !== self::TYPE_EMAIL) {
+      $typeName .= ", format='$format'";
     }
 
     return $typeName;
diff --git a/Core/API/Traits/Pagination.trait.php b/Core/API/Traits/Pagination.trait.php
index f46adf9..9a3edeb 100644
--- a/Core/API/Traits/Pagination.trait.php
+++ b/Core/API/Traits/Pagination.trait.php
@@ -12,7 +12,8 @@ use Core\Objects\DatabaseEntity\User;
 
 trait Pagination {
 
-  static function getPaginationParameters(array $orderColumns, string $defaultOrderBy = "id", string $defaultSortOrder = "asc"): array {
+  function getPaginationParameters(array $orderColumns, string $defaultOrderBy = "id", string $defaultSortOrder = "asc"): array {
+    $this->paginationOrderColumns = $orderColumns;
     return [
       'page' => new Parameter('page', Parameter::TYPE_INT, true, 1),
       'count' => new Parameter('count', Parameter::TYPE_INT, true, 20),
diff --git a/Core/Driver/SQL/Expression/Coalesce.class.php b/Core/Driver/SQL/Expression/Coalesce.class.php
new file mode 100644
index 0000000..d84a70e
--- /dev/null
+++ b/Core/Driver/SQL/Expression/Coalesce.class.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace Core\Driver\SQL\Expression;
+
+use Core\Driver\SQL\SQL;
+
+class Coalesce extends Expression {
+
+  private array $values;
+
+  public function __construct(mixed ...$values) {
+    $this->values = $values;
+  }
+
+  function getExpression(SQL $sql, array &$params): string {
+    $values = implode(",", array_map(function ($value) use ($sql, &$params) {
+      if (is_string($value)) {
+        return $sql->columnName($value);
+      } else {
+        return $sql->addValue($value, $params);
+      }
+    }, $this->values));
+    return "COALESCE($values)";
+  }
+}
\ No newline at end of file
diff --git a/Core/Driver/SQL/Expression/NullIf.class.php b/Core/Driver/SQL/Expression/NullIf.class.php
new file mode 100644
index 0000000..42f751a
--- /dev/null
+++ b/Core/Driver/SQL/Expression/NullIf.class.php
@@ -0,0 +1,22 @@
+<?php
+
+namespace Core\Driver\SQL\Expression;
+
+use Core\Driver\SQL\SQL;
+
+class NullIf extends Expression {
+
+  private mixed $lhs;
+  private mixed $rhs;
+
+  public function __construct(mixed $lhs, mixed $rhs) {
+    $this->lhs = $lhs;
+    $this->rhs = $rhs;
+  }
+
+  function getExpression(SQL $sql, array &$params): string {
+    $lhs = $sql->addValue($this->lhs, $params);
+    $rhs = $sql->addValue($this->rhs, $params);
+    return "NULLIF($lhs, $rhs)";
+  }
+}
\ No newline at end of file
diff --git a/Core/Objects/DatabaseEntity/Controller/DatabaseEntity.class.php b/Core/Objects/DatabaseEntity/Controller/DatabaseEntity.class.php
index 1b2f5e6..4a40ad2 100644
--- a/Core/Objects/DatabaseEntity/Controller/DatabaseEntity.class.php
+++ b/Core/Objects/DatabaseEntity/Controller/DatabaseEntity.class.php
@@ -109,7 +109,7 @@ abstract class DatabaseEntity implements ArrayAccess, JsonSerializable {
       }
     }
 
-    if ($propertyNames === null) {
+    if ($propertyNames === null && !empty($this->customData)) {
       $jsonArray = array_merge($jsonArray, $this->customData);
     }
 
diff --git a/Core/Objects/DatabaseEntity/Controller/DatabaseEntityHandler.php b/Core/Objects/DatabaseEntity/Controller/DatabaseEntityHandler.php
index 859b16f..c194f22 100644
--- a/Core/Objects/DatabaseEntity/Controller/DatabaseEntityHandler.php
+++ b/Core/Objects/DatabaseEntity/Controller/DatabaseEntityHandler.php
@@ -74,6 +74,9 @@ class DatabaseEntityHandler implements Persistable {
   }
 
   public function init() {
+    $className = $this->entityClass->getName();
+
+
     $uniqueColumns = self::getAttribute($this->entityClass, Unique::class);
     if ($uniqueColumns) {
       $this->constraints[] = new \Core\Driver\SQL\Constraint\Unique($uniqueColumns->getColumns());
diff --git a/Core/Objects/DatabaseEntity/Controller/NMRelation.class.php b/Core/Objects/DatabaseEntity/Controller/NMRelation.class.php
index de48ae7..4ed0439 100644
--- a/Core/Objects/DatabaseEntity/Controller/NMRelation.class.php
+++ b/Core/Objects/DatabaseEntity/Controller/NMRelation.class.php
@@ -58,9 +58,9 @@ class NMRelation implements Persistable {
 
   public function getOtherHandler(DatabaseEntityHandler $handler): DatabaseEntityHandler {
     if ($handler === $this->thisHandler) {
-      return $this->thisHandler;
-    } else {
       return $this->otherHandler;
+    } else {
+      return $this->thisHandler;
     }
   }
 }
\ No newline at end of file