diff --git a/src/Currency.php b/src/Currency.php
index ffdfdce..7be20d4 100644
--- a/src/Currency.php
+++ b/src/Currency.php
@@ -2,6 +2,7 @@
 namespace ProVM\Money;
 
 use ProVM\Common\Alias\Model;
+use ProVM\Common\Factory\Model as ModelFactory;
 
 /**
  * @property int $id
@@ -16,5 +17,47 @@ class Currency extends Model {
     if ($this->values === null) {
       $this->values = $this->parentOf(Value::class, [Model::CHILD_KEY => 'currency_id']);
     }
+    return $this->values;
+  }
+
+  protected static $fields = ['code', 'name'];
+  public static function add(ModelFactory $factory, $info) {
+    $input = array_intersect_key((array) $info, array_combine(self::$fields, self::$fields));
+    $currency = $factory->find(Currency::class)->where([['code', $input['code']]])->one();
+    $created = false;
+    $result = (object) compact('input', 'currency', 'created');
+    if (!$currency) {
+      $currency = $factory->create(Currency::class, $input);
+      $created = $currency->save();
+      $result->created = $created;
+    }
+    $result->currency = $currency->asArray();
+    return $result;
+  }
+  protected function checkCode(string $code): bool {
+    return ($this->find(Currency::class)->where([['code', $code]])->one()) ? true : false;
+  }
+  public function edit($info) {
+    $data = array_intersect_key((array) $info, array_combine(self::$fields, self::$fields));
+    $edited = false;
+    foreach ($data as $field => $value) {
+      if ($this->{$field} != $value) {
+        if ($field == 'code' and $this->checkCode($value)) {
+          throw \Exception('Currency code ' . $value . ' is already in the database.');
+        }
+        $this->{$field} = $value;
+        $edited = true;
+      }
+    }
+    if ($edited) {
+      $edited = $this->save();
+    }
+    return $edited;
+  }
+  public function addValue($info) {
+    $arr = (array) $info;
+    $arr['currency_id'] = (int) $this->id;
+    $result = Value::add($this->factory, $arr);
+    return $result;
   }
 }
diff --git a/src/Value.php b/src/Value.php
index 319d73a..66824aa 100644
--- a/src/Value.php
+++ b/src/Value.php
@@ -3,6 +3,7 @@ namespace ProVM\Money;
 
 use ProVM\Common\Alias\Model;
 use ProVM\Common\Define\Model\DateTime;
+use ProVM\Common\Factory\Model as ModelFactory;
 
 /**
  * @property Currency $currency_id
@@ -10,10 +11,11 @@ use ProVM\Common\Define\Model\DateTime;
  * @property double $value
  * @property Currency $base_id
  */
-class Value {
+class Value extends Model {
   use DateTime;
 
   public static $_table = 'values';
+  public static $_id_column = ['currency_id', 'base_id', 'date_time'];
 
   protected $currency;
   public function currency(): ?Currency {
@@ -29,4 +31,43 @@ class Value {
     }
     return $this->base;
   }
+
+  protected static $fields = ['currency_id', 'date_time', 'value', 'base_id'];
+  public static function add(ModelFactory $factory, $info) {
+    $input = array_intersect_key((array) $info, array_combine(self::$fields, self::$fields));
+    $value = $factory->find(Value::class)->where([['currency_id', $input['currency_id']], ['date_time', $input['date_time']], ['base_id', $input['base_id']]])->one();
+    $created = false;
+    $result = (object) compact('input', 'value', 'created');
+    if (!$value) {
+      $value = $factory->create(Value::class, $input);
+      $created = $value->save();
+      $result->created = $created;
+    }
+    $result->value = $value->asArray();
+    return $result;
+  }
+  public function edit($info) {
+    $data = array_intersect_key((array) $info, array_combine(self::$fields, self::$fields));
+    $edited = false;
+    foreach ($data as $field => $value) {
+      if ($this->{$field} != $value) {
+        if ($field == 'currency_id' or $field == 'base_id') {
+          continue;
+        }
+        $this->{$field} = $value;
+        $edited = true;
+      }
+    }
+    if ($edited) {
+      $edited = $this->save();
+    }
+    return $edited;
+  }
+  public function asArray(): array {
+    $output = parent::asArray();
+    $output['currency'] = $this->currency()->asArray();
+    $output['base'] = $this->base()->asArray();
+    $output['date_time'] = $this->dateTime()->format('Y-m-d H:i:s');
+    return $output;
+  }
 }