Use BigDecimal for Currency exchange rate.

src/Validator/Constraints/BigDecimal/BigDecimalPositive.php

@@ -0,0 +1,49 @@
+<?php
+/**
+ * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
+ *
+ * Copyright (C) 2019 - 2020 Jan Böhmer (https://github.com/jbtronics)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+namespace App\Validator\Constraints\BigDecimal;
+
+
+use Symfony\Component\Validator\Constraints\GreaterThan;
+use Symfony\Component\Validator\Constraints\GreaterThanValidator;
+use Symfony\Component\Validator\Constraints\NumberConstraintTrait;
+
+/**
+ * @Annotation
+ * @Target({"PROPERTY", "METHOD", "ANNOTATION"})
+ *
+ * @author Jan Schädlich <jan.schaedlich@sensiolabs.de>
+ */
+class BigDecimalPositive extends GreaterThan
+{
+    use NumberConstraintTrait;
+
+    public $message = 'This value should be positive.';
+
+    public function __construct($options = null)
+    {
+        parent::__construct($this->configureNumberConstraintOptions($options));
+    }
+
+    public function validatedBy(): string
+    {
+        return BigDecimalGreaterThanValidator::class;
+    }
+}