diff --git a/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/DataPageBuilder.php b/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/DataPageBuilder.php
index 7798d8baf..d69582132 100644
--- a/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/DataPageBuilder.php
+++ b/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/DataPageBuilder.php
@@ -51,7 +51,7 @@ public function build(FlatColumn $column, array $rows, ?array $dictionary = null
             \strlen($pageBuffer),
             dataPageHeader: new DataPageHeader(
                 $dictionary && $indices ? Encodings::RLE_DICTIONARY : Encodings::PLAIN,
-                $dictionary && $indices ? \count($indices) : \count($shredded->values),
+                \count($shredded->definitions)
             ),
             dataPageHeaderV2: null,
             dictionaryPageHeader: null,
diff --git a/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/DictionaryBuilder/FloatDictionaryBuilder.php b/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/DictionaryBuilder/FloatDictionaryBuilder.php
index e7bdb30a3..999024587 100644
--- a/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/DictionaryBuilder/FloatDictionaryBuilder.php
+++ b/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/DictionaryBuilder/FloatDictionaryBuilder.php
@@ -15,6 +15,10 @@ public function build(array $rows) : Dictionary
         $dictionarySize = 0;
 
         foreach (array_flatten($rows) as $value) {
+            if ($value === null) {
+                continue;
+            }
+
             $hash = \serialize($value);
 
             if (!isset($valueToIndex[$hash])) {
diff --git a/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/DictionaryBuilder/ObjectDictionaryBuilder.php b/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/DictionaryBuilder/ObjectDictionaryBuilder.php
index 711050830..457107b77 100644
--- a/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/DictionaryBuilder/ObjectDictionaryBuilder.php
+++ b/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/DictionaryBuilder/ObjectDictionaryBuilder.php
@@ -15,6 +15,10 @@ public function build(array $rows) : Dictionary
         $dictionarySize = 0;
 
         foreach (array_flatten($rows) as $value) {
+            if ($value === null) {
+                continue;
+            }
+
             $hash = \serialize($value);
 
             if (!isset($valueToIndex[$hash])) {
diff --git a/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/DictionaryBuilder/ScalarDictionaryBuilder.php b/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/DictionaryBuilder/ScalarDictionaryBuilder.php
index c76abc84b..a4993b4a1 100644
--- a/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/DictionaryBuilder/ScalarDictionaryBuilder.php
+++ b/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/DictionaryBuilder/ScalarDictionaryBuilder.php
@@ -15,6 +15,10 @@ public function build(array $rows) : Dictionary
         $dictionarySize = 0;
 
         foreach (array_flatten($rows) as $value) {
+            if ($value === null) {
+                continue;
+            }
+
             if (!isset($valueToIndex[$value])) {
                 $dictionary[] = $value;
                 $valueToIndex[$value] = $dictionarySize;
diff --git a/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/PlainValuesPacker.php b/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/PlainValuesPacker.php
index 4f8090404..798fb3a87 100644
--- a/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/PlainValuesPacker.php
+++ b/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageBuilder/PlainValuesPacker.php
@@ -21,6 +21,10 @@ public function packValues(FlatColumn $column, array $values) : string
         $parquetValues = [];
 
         foreach ($values as $value) {
+            if ($value === null) {
+                continue;
+            }
+
             $parquetValues[] = $this->dataConverter->toParquetType($column, $value);
         }
 
diff --git a/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageContainers.php b/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageContainers.php
index c47076346..773fb3818 100644
--- a/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageContainers.php
+++ b/src/lib/parquet/src/Flow/Parquet/ParquetFile/RowGroupBuilder/PageContainers.php
@@ -99,10 +99,6 @@ public function size() : int
 
     public function valuesCount() : int
     {
-        if ($this->dictionaryPageContainer !== null) {
-            return \count($this->dictionaryPageContainer->values);
-        }
-
         $count = 0;
 
         foreach ($this->dataPageContainers as $pageContainer) {
diff --git a/src/lib/parquet/tests/Flow/Parquet/Tests/Integration/IO/SimpleTypesWritingTest.php b/src/lib/parquet/tests/Flow/Parquet/Tests/Integration/IO/SimpleTypesWritingTest.php
index f2e741402..6afc802df 100644
--- a/src/lib/parquet/tests/Flow/Parquet/Tests/Integration/IO/SimpleTypesWritingTest.php
+++ b/src/lib/parquet/tests/Flow/Parquet/Tests/Integration/IO/SimpleTypesWritingTest.php
@@ -32,11 +32,35 @@ public function test_writing_bool_column() : void
             $inputData,
             \iterator_to_array((new Reader())->read($path)->values())
         );
+
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_bool_nullable_column() : void
     {
-        $this->markTestSkipped('Not implemented yet');
+        $path = \sys_get_temp_dir() . '/test-writer' . \uniqid('parquet-test-', true) . '.parquet';
+
+        $writer = new Writer();
+        $schema = Schema::with(FlatColumn::boolean('boolean'));
+
+        $inputData = \array_merge(...\array_map(static function (int $i) : array {
+            return [
+                [
+                    'boolean' => $i % 2 == 0 ? (bool) \random_int(0, 1) : null,
+                ],
+            ];
+        }, \range(1, 100)));
+
+        $writer->write($path, $schema, $inputData);
+
+        $this->assertSame(
+            $inputData,
+            \iterator_to_array((new Reader())->read($path)->values())
+        );
+
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_date_column() : void
@@ -62,11 +86,37 @@ public function test_writing_date_column() : void
             $inputData,
             \iterator_to_array((new Reader())->read($path)->values())
         );
+
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_date_nullable_column() : void
     {
-        $this->markTestSkipped('Not implemented yet');
+        $path = \sys_get_temp_dir() . '/test-writer' . \uniqid('parquet-test-', true) . '.parquet';
+
+        $writer = new Writer();
+        $schema = Schema::with(FlatColumn::date('date'));
+
+        $faker = Factory::create();
+
+        $inputData = \array_merge(...\array_map(static function (int $i) use ($faker) : array {
+            return [
+                [
+                    'date' => $i % 2 === 0 ? \DateTimeImmutable::createFromMutable($faker->dateTimeThisYear)->setTime(0, 0, 0, 0) : null,
+                ],
+            ];
+        }, \range(1, 100)));
+
+        $writer->write($path, $schema, $inputData);
+
+        $this->assertEquals(
+            $inputData,
+            \iterator_to_array((new Reader())->read($path)->values())
+        );
+
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_decimal_column() : void
@@ -92,11 +142,37 @@ public function test_writing_decimal_column() : void
             $inputData,
             \iterator_to_array((new Reader())->read($path)->values())
         );
+
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_decimal_nullable_column() : void
     {
-        $this->markTestSkipped('Not implemented yet');
+        $path = \sys_get_temp_dir() . '/test-writer' . \uniqid('parquet-test-', true) . '.parquet';
+
+        $writer = new Writer();
+        $schema = Schema::with(FlatColumn::decimal('decimal'));
+
+        $faker = Factory::create();
+
+        $inputData = \array_merge(...\array_map(static function (int $i) use ($faker) : array {
+            return [
+                [
+                    'decimal' => $i % 2 === 0 ? \round($faker->randomFloat(5), 2) : null,
+                ],
+            ];
+        }, \range(1, 100)));
+
+        $writer->write($path, $schema, $inputData);
+
+        $this->assertEquals(
+            $inputData,
+            \iterator_to_array((new Reader())->read($path)->values())
+        );
+
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_double_column() : void
@@ -122,11 +198,37 @@ public function test_writing_double_column() : void
             $inputData,
             \iterator_to_array((new Reader())->read($path)->values())
         );
+
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_double_nullable_column() : void
     {
-        $this->markTestSkipped('Not implemented yet');
+        $path = \sys_get_temp_dir() . '/test-writer' . \uniqid('parquet-test-', true) . '.parquet';
+
+        $writer = new Writer();
+        $schema = Schema::with(FlatColumn::double('double'));
+
+        $faker = Factory::create();
+
+        $inputData = \array_merge(...\array_map(static function (int $i) use ($faker) : array {
+            return [
+                [
+                    'double' => $i % 2 === 0 ? $faker->randomFloat() : null,
+                ],
+            ];
+        }, \range(1, 100)));
+
+        $writer->write($path, $schema, $inputData);
+
+        $this->assertEquals(
+            $inputData,
+            \iterator_to_array((new Reader())->read($path)->values())
+        );
+
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_enum_column() : void
@@ -155,11 +257,35 @@ public function test_writing_float_column() : void
             $inputData,
             \iterator_to_array((new Reader())->read($path)->values())
         );
+
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_float_nullable_column() : void
     {
-        $this->markTestSkipped('Not implemented yet');
+        $path = \sys_get_temp_dir() . '/test-writer' . \uniqid('parquet-test-', true) . '.parquet';
+
+        $writer = new Writer();
+        $schema = Schema::with(FlatColumn::float('float'));
+
+        $inputData = \array_merge(...\array_map(static function (int $i) : array {
+            return [
+                [
+                    'float' => $i % 2 === 0 ? 10.25 : null,
+                ],
+            ];
+        }, \range(1, 100)));
+
+        $writer->write($path, $schema, $inputData);
+
+        $this->assertEquals(
+            $inputData,
+            \iterator_to_array((new Reader())->read($path)->values())
+        );
+
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_int32_column() : void
@@ -185,11 +311,37 @@ public function test_writing_int32_column() : void
             $inputData,
             \iterator_to_array((new Reader())->read($path)->values())
         );
+
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_int32_nullable_column() : void
     {
-        $this->markTestSkipped('Not implemented yet');
+        $path = \sys_get_temp_dir() . '/test-writer' . \uniqid('parquet-test-', true) . '.parquet';
+
+        $writer = new Writer();
+        $schema = Schema::with(FlatColumn::int32('int32'));
+
+        $faker = Factory::create();
+
+        $inputData = \array_merge(...\array_map(static function (int $i) use ($faker) : array {
+            return [
+                [
+                    'int32' => $i % 2 === 0 ? $faker->numberBetween(0, Consts::PHP_INT32_MAX) : null,
+                ],
+            ];
+        }, \range(1, 100)));
+
+        $writer->write($path, $schema, $inputData);
+
+        $this->assertEquals(
+            $inputData,
+            \iterator_to_array((new Reader())->read($path)->values())
+        );
+
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_int64() : void
@@ -215,11 +367,35 @@ public function test_writing_int64() : void
             $inputData,
             \iterator_to_array((new Reader())->read($path)->values())
         );
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_int64_nullable_column() : void
     {
-        $this->markTestSkipped('Not implemented yet');
+        $path = \sys_get_temp_dir() . '/test-writer' . \uniqid('parquet-test-', true) . '.parquet';
+
+        $writer = new Writer();
+        $schema = Schema::with(FlatColumn::int64('int64'));
+
+        $faker = Factory::create();
+
+        $inputData = \array_merge(...\array_map(static function (int $i) use ($faker) : array {
+            return [
+                [
+                    'int64' => $i % 2 === 0 ? $faker->numberBetween(0, Consts::PHP_INT64_MAX) : null,
+                ],
+            ];
+        }, \range(1, 100)));
+
+        $writer->write($path, $schema, $inputData);
+
+        $this->assertEquals(
+            $inputData,
+            \iterator_to_array((new Reader())->read($path)->values())
+        );
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_json_column() : void
@@ -245,11 +421,37 @@ public function test_writing_json_column() : void
             $inputData,
             \iterator_to_array((new Reader())->read($path)->values())
         );
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_json_nullable_column() : void
     {
-        $this->markTestSkipped('Not implemented yet');
+        $path = \sys_get_temp_dir() . '/test-writer' . \uniqid('parquet-test-', true) . '.parquet';
+
+        $writer = new Writer();
+        $schema = Schema::with(FlatColumn::json('json'));
+
+        $faker = Factory::create();
+
+        $inputData = \array_merge(...\array_map(static function (int $i) use ($faker) : array {
+            return [
+                [
+                    'json' => $i % 2 === 0
+                        ? \json_encode(['street' => $faker->streetName, 'city' => $faker->city, 'country' => $faker->country, 'zip' => $faker->postcode], JSON_THROW_ON_ERROR)
+                        : null,
+                ],
+            ];
+        }, \range(1, 100)));
+
+        $writer->write($path, $schema, $inputData);
+
+        $this->assertEquals(
+            $inputData,
+            \iterator_to_array((new Reader())->read($path)->values())
+        );
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_string_column() : void
@@ -275,11 +477,35 @@ public function test_writing_string_column() : void
             $inputData,
             \iterator_to_array((new Reader())->read($path)->values())
         );
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_string_nullable_column() : void
     {
-        $this->markTestSkipped('Not implemented yet');
+        $path = \sys_get_temp_dir() . '/test-writer' . \uniqid('parquet-test-', true) . '.parquet';
+
+        $writer = new Writer();
+        $schema = Schema::with(FlatColumn::string('string'));
+
+        $faker = Factory::create();
+
+        $inputData = \array_merge(...\array_map(static function (int $i) use ($faker) : array {
+            return [
+                [
+                    'string' => $i % 2 === 0 ? $faker->text(50) : null,
+                ],
+            ];
+        }, \range(1, 100)));
+
+        $writer->write($path, $schema, $inputData);
+
+        $this->assertEquals(
+            $inputData,
+            \iterator_to_array((new Reader())->read($path)->values())
+        );
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_time_column() : void
@@ -303,11 +529,33 @@ public function test_writing_time_column() : void
             $inputData,
             \iterator_to_array((new Reader())->read($path)->values())
         );
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_time_nullable_column() : void
     {
-        $this->markTestSkipped('Not implemented yet');
+        $path = \sys_get_temp_dir() . '/test-writer' . \uniqid('parquet-test-', true) . '.parquet';
+
+        $writer = new Writer();
+        $schema = Schema::with(FlatColumn::time('time'));
+
+        $inputData = \array_merge(...\array_map(static function (int $i) : array {
+            return [
+                [
+                    'time' => $i % 2 === 0 ? (new \DateTimeImmutable('2023-01-01 00:00:00 UTC'))->diff(new \DateTimeImmutable('2023-01-01 15:45:00 UTC')) : null,
+                ],
+            ];
+        }, \range(1, 100)));
+
+        $writer->write($path, $schema, $inputData);
+
+        $this->assertEquals(
+            $inputData,
+            \iterator_to_array((new Reader())->read($path)->values())
+        );
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_timestamp_column() : void
@@ -333,11 +581,35 @@ public function test_writing_timestamp_column() : void
             $inputData,
             \iterator_to_array((new Reader())->read($path)->values())
         );
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_timestamp_nullable_column() : void
     {
-        $this->markTestSkipped('Not implemented yet');
+        $path = \sys_get_temp_dir() . '/test-writer' . \uniqid('parquet-test-', true) . '.parquet';
+
+        $writer = new Writer();
+        $schema = Schema::with(FlatColumn::dateTime('dateTime'));
+
+        $faker = Factory::create();
+
+        $inputData = \array_merge(...\array_map(static function (int $i) use ($faker) : array {
+            return [
+                [
+                    'dateTime' => $i % 2 === 0 ? $faker->dateTimeThisYear : null,
+                ],
+            ];
+        }, \range(1, 100)));
+
+        $writer->write($path, $schema, $inputData);
+
+        $this->assertEquals(
+            $inputData,
+            \iterator_to_array((new Reader())->read($path)->values())
+        );
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_uuid_column() : void
@@ -363,10 +635,34 @@ public function test_writing_uuid_column() : void
             $inputData,
             \iterator_to_array((new Reader())->read($path)->values())
         );
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 
     public function test_writing_uuid_nullable_column() : void
     {
-        $this->markTestSkipped('Not implemented yet');
+        $path = \sys_get_temp_dir() . '/test-writer' . \uniqid('parquet-test-', true) . '.parquet';
+
+        $writer = new Writer();
+        $schema = Schema::with(FlatColumn::uuid('uuid'));
+
+        $faker = Factory::create();
+
+        $inputData = \array_merge(...\array_map(static function (int $i) use ($faker) : array {
+            return [
+                [
+                    'uuid' => $i % 2 === 0 ? $faker->uuid : null,
+                ],
+            ];
+        }, \range(1, 100)));
+
+        $writer->write($path, $schema, $inputData);
+
+        $this->assertEquals(
+            $inputData,
+            \iterator_to_array((new Reader())->read($path)->values())
+        );
+        $this->assertTrue(\file_exists($path));
+        \unlink($path);
     }
 }