Address issue doctrine#3631 by adding support for a float datatype

Also try to add a new functional test per request.

.travis.yml

@@ -36,6 +36,11 @@ after_script:
       travis_retry php ocular.phar code-coverage:upload --format=php-clover clover.xml
     fi
 
+addons:
+  apt:
+    packages:
+      - language-pack-de
+
 jobs:
   allow_failures:
     - php: 7.4snapshot

lib/Doctrine/DBAL/Driver/Mysqli/MysqliStatement.php

@@ -34,6 +34,7 @@ class MysqliStatement implements IteratorAggregate, Statement
         ParameterType::NULL         => 's',
         ParameterType::INTEGER      => 'i',
         ParameterType::LARGE_OBJECT => 'b',
+        ParameterType::DOUBLE       => 'd',
     ];
 
     /** @var mysqli */

lib/Doctrine/DBAL/ParameterType.php

@@ -49,6 +49,11 @@ final class ParameterType
      */
     public const BINARY = 16;
 
+    /**
+     * Represents a double data type.
+     */
+    public const DOUBLE = 17;
+
     /**
      * This class cannot be instantiated.
      */

lib/Doctrine/DBAL/Types/FloatType.php

@@ -2,6 +2,7 @@
 
 namespace Doctrine\DBAL\Types;
 
+use Doctrine\DBAL\ParameterType;
 use Doctrine\DBAL\Platforms\AbstractPlatform;
 
 class FloatType extends Type
@@ -29,4 +30,12 @@ public function convertToPHPValue($value, AbstractPlatform $platform)
     {
         return $value === null ? null : (float) $value;
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getBindingType()
+    {
+        return ParameterType::DOUBLE;
+    }
 }

tests/Doctrine/Tests/DBAL/Functional/Types/DoubleTest.php

@@ -0,0 +1,83 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\Tests\DBAL\Functional\Types;
+
+use Doctrine\DBAL\ParameterType;
+use Doctrine\DBAL\Schema\Table;
+use Doctrine\Tests\DbalFunctionalTestCase;
+use function microtime;
+
+class DoubleTest extends DbalFunctionalTestCase
+{
+    protected function setUp() : void
+    {
+        parent::setUp();
+
+        $table = new Table('double_table');
+        $table->addColumn('id', 'integer');
+        $table->addColumn('val', 'float');
+        $table->setPrimaryKey(['id']);
+
+        $sm = $this->connection->getSchemaManager();
+        $sm->dropAndCreateTable($table);
+    }
+
+    public function testInsertAndSelect() : void
+    {
+        $value1 = 1.0;
+        $value2 = 77.99999999999;
+        $value3 = microtime(true);
+
+        $this->insert(1, $value1);
+        $this->insert(2, $value2);
+        $this->insert(3, $value3);
+
+        $this->assertSame($value1, $this->select(1));
+        $this->assertSame($value2, $this->select(2));
+        $this->assertSame($value3, $this->select(3));
+        $this->assertSame(1, $this->selectDouble($value1));
+        $this->assertSame(2, $this->selectDouble($value2));
+        $this->assertSame(3, $this->selectDouble($value3));
+    }
+
+    private function insert(int $id, float $value) : void
+    {
+        $result = $this->connection->insert('double_table', [
+            'id'  => $id,
+            'val' => $value,
+        ], [
+            ParameterType::INTEGER,
+            ParameterType::DOUBLE,
+        ]);
+
+        self::assertSame(1, $result);
+    }
+
+    /**
+     * @return mixed
+     */
+    private function select(int $id)
+    {
+        return $this->connection->fetchColumn(
+            'SELECT val FROM double_table WHERE id = ?',
+            [$id],
+            0,
+            [ParameterType::INTEGER]
+        );
+    }
+
+    /**
+     * @return mixed
+     */
+    private function selectDouble(float $value)
+    {
+        return $this->connection->fetchColumn(
+            'SELECT id FROM double_table WHERE val = ?',
+            [$value],
+            0,
+            [ParameterType::DOUBLE]
+        );
+    }
+}