diff --git a/lib/Doctrine/DBAL/Platforms/OraclePlatform.php b/lib/Doctrine/DBAL/Platforms/OraclePlatform.php
index 32b12a0bc1f..7a1cd574427 100644
--- a/lib/Doctrine/DBAL/Platforms/OraclePlatform.php
+++ b/lib/Doctrine/DBAL/Platforms/OraclePlatform.php
@@ -36,7 +36,6 @@
 use function implode;
 use function preg_match;
 use function sprintf;
-use function str_replace;
 use function strlen;
 use function strpos;
 use function strtoupper;
@@ -1180,14 +1179,4 @@ public function getBlobTypeDeclarationSQL(array $field)
     {
         return 'BLOB';
     }
-
-    /**
-     * {@inheritdoc}
-     */
-    public function quoteStringLiteral($str)
-    {
-        $str = str_replace('\\', '\\\\', $str); // Oracle requires backslashes to be escaped aswell.
-
-        return parent::quoteStringLiteral($str);
-    }
 }
diff --git a/lib/Doctrine/DBAL/Platforms/PostgreSqlPlatform.php b/lib/Doctrine/DBAL/Platforms/PostgreSqlPlatform.php
index 64666b5672b..f7fb1eccdc9 100644
--- a/lib/Doctrine/DBAL/Platforms/PostgreSqlPlatform.php
+++ b/lib/Doctrine/DBAL/Platforms/PostgreSqlPlatform.php
@@ -42,7 +42,6 @@
 use function is_bool;
 use function is_numeric;
 use function is_string;
-use function str_replace;
 use function strpos;
 use function strtolower;
 use function trim;
@@ -1205,16 +1204,6 @@ public function getBlobTypeDeclarationSQL(array $field)
         return 'BYTEA';
     }
 
-    /**
-     * {@inheritdoc}
-     */
-    public function quoteStringLiteral($str)
-    {
-        $str = str_replace('\\', '\\\\', $str); // PostgreSQL requires backslashes to be escaped aswell.
-
-        return parent::quoteStringLiteral($str);
-    }
-
     /**
      * {@inheritdoc}
      */
diff --git a/tests/Doctrine/Tests/DBAL/Functional/Platform/QuotingTest.php b/tests/Doctrine/Tests/DBAL/Functional/Platform/QuotingTest.php
new file mode 100644
index 00000000000..0cf326ad2ae
--- /dev/null
+++ b/tests/Doctrine/Tests/DBAL/Functional/Platform/QuotingTest.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace Doctrine\Tests\DBAL\Functional\Platform;
+
+use Doctrine\Tests\DbalFunctionalTestCase;
+
+class QuotingTest extends DbalFunctionalTestCase
+{
+    /**
+     * @dataProvider stringLiteralProvider
+     */
+    public function testQuoteStringLiteral(string $string) : void
+    {
+        $platform = $this->_conn->getDatabasePlatform();
+        $query    = $platform->getDummySelectSQL(
+            $platform->quoteStringLiteral($string)
+        );
+
+        self::assertSame($string, $this->_conn->fetchColumn($query));
+    }
+
+    /**
+     * @return mixed[][]
+     */
+    public static function stringLiteralProvider() : iterable
+    {
+        return [
+            'backslash' => ['\\'],
+            'single-quote' => ["'"],
+        ];
+    }
+}
diff --git a/tests/Doctrine/Tests/DBAL/Platforms/AbstractPostgreSqlPlatformTestCase.php b/tests/Doctrine/Tests/DBAL/Platforms/AbstractPostgreSqlPlatformTestCase.php
index 6732ad339ac..23da589cb1e 100644
--- a/tests/Doctrine/Tests/DBAL/Platforms/AbstractPostgreSqlPlatformTestCase.php
+++ b/tests/Doctrine/Tests/DBAL/Platforms/AbstractPostgreSqlPlatformTestCase.php
@@ -922,7 +922,7 @@ public function testReturnsCloseActiveDatabaseConnectionsSQL()
      */
     public function testQuotesTableNameInListTableForeignKeysSQL()
     {
-        self::assertContains("'Foo''Bar\\\\'", $this->_platform->getListTableForeignKeysSQL("Foo'Bar\\"), '', true);
+        self::assertContains("'Foo''Bar\\'", $this->_platform->getListTableForeignKeysSQL("Foo'Bar\\"), '', true);
     }
 
     /**
@@ -931,7 +931,7 @@ public function testQuotesTableNameInListTableForeignKeysSQL()
     public function testQuotesSchemaNameInListTableForeignKeysSQL()
     {
         self::assertContains(
-            "'Foo''Bar\\\\'",
+            "'Foo''Bar\\'",
             $this->_platform->getListTableForeignKeysSQL("Foo'Bar\\.baz_table"),
             '',
             true
@@ -943,7 +943,7 @@ public function testQuotesSchemaNameInListTableForeignKeysSQL()
      */
     public function testQuotesTableNameInListTableConstraintsSQL()
     {
-        self::assertContains("'Foo''Bar\\\\'", $this->_platform->getListTableConstraintsSQL("Foo'Bar\\"), '', true);
+        self::assertContains("'Foo''Bar\\'", $this->_platform->getListTableConstraintsSQL("Foo'Bar\\"), '', true);
     }
 
     /**
@@ -951,7 +951,7 @@ public function testQuotesTableNameInListTableConstraintsSQL()
      */
     public function testQuotesTableNameInListTableIndexesSQL()
     {
-        self::assertContains("'Foo''Bar\\\\'", $this->_platform->getListTableIndexesSQL("Foo'Bar\\"), '', true);
+        self::assertContains("'Foo''Bar\\'", $this->_platform->getListTableIndexesSQL("Foo'Bar\\"), '', true);
     }
 
     /**
@@ -960,7 +960,7 @@ public function testQuotesTableNameInListTableIndexesSQL()
     public function testQuotesSchemaNameInListTableIndexesSQL()
     {
         self::assertContains(
-            "'Foo''Bar\\\\'",
+            "'Foo''Bar\\'",
             $this->_platform->getListTableIndexesSQL("Foo'Bar\\.baz_table"),
             '',
             true
@@ -972,7 +972,7 @@ public function testQuotesSchemaNameInListTableIndexesSQL()
      */
     public function testQuotesTableNameInListTableColumnsSQL()
     {
-        self::assertContains("'Foo''Bar\\\\'", $this->_platform->getListTableColumnsSQL("Foo'Bar\\"), '', true);
+        self::assertContains("'Foo''Bar\\'", $this->_platform->getListTableColumnsSQL("Foo'Bar\\"), '', true);
     }
 
     /**
@@ -981,7 +981,7 @@ public function testQuotesTableNameInListTableColumnsSQL()
     public function testQuotesSchemaNameInListTableColumnsSQL()
     {
         self::assertContains(
-            "'Foo''Bar\\\\'",
+            "'Foo''Bar\\'",
             $this->_platform->getListTableColumnsSQL("Foo'Bar\\.baz_table"),
             '',
             true
@@ -994,7 +994,7 @@ public function testQuotesSchemaNameInListTableColumnsSQL()
     public function testQuotesDatabaseNameInCloseActiveDatabaseConnectionsSQL()
     {
         self::assertContains(
-            "'Foo''Bar\\\\'",
+            "'Foo''Bar\\'",
             $this->_platform->getCloseActiveDatabaseConnectionsSQL("Foo'Bar\\"),
             '',
             true
diff --git a/tests/Doctrine/Tests/DBAL/Platforms/OraclePlatformTest.php b/tests/Doctrine/Tests/DBAL/Platforms/OraclePlatformTest.php
index 5e270b4a1e7..41adb66df8b 100644
--- a/tests/Doctrine/Tests/DBAL/Platforms/OraclePlatformTest.php
+++ b/tests/Doctrine/Tests/DBAL/Platforms/OraclePlatformTest.php
@@ -845,7 +845,7 @@ protected function getGeneratesAlterTableRenameIndexUsedByForeignKeySQL()
      */
     public function testQuotesDatabaseNameInListSequencesSQL()
     {
-        self::assertContains("'Foo''Bar\\\\'", $this->_platform->getListSequencesSQL("Foo'Bar\\"), '', true);
+        self::assertContains("'Foo''Bar\\'", $this->_platform->getListSequencesSQL("Foo'Bar\\"), '', true);
     }
 
     /**
@@ -853,7 +853,7 @@ public function testQuotesDatabaseNameInListSequencesSQL()
      */
     public function testQuotesTableNameInListTableIndexesSQL()
     {
-        self::assertContains("'Foo''Bar\\\\'", $this->_platform->getListTableIndexesSQL("Foo'Bar\\"), '', true);
+        self::assertContains("'Foo''Bar\\'", $this->_platform->getListTableIndexesSQL("Foo'Bar\\"), '', true);
     }
 
     /**
@@ -861,7 +861,7 @@ public function testQuotesTableNameInListTableIndexesSQL()
      */
     public function testQuotesTableNameInListTableForeignKeysSQL()
     {
-        self::assertContains("'Foo''Bar\\\\'", $this->_platform->getListTableForeignKeysSQL("Foo'Bar\\"), '', true);
+        self::assertContains("'Foo''Bar\\'", $this->_platform->getListTableForeignKeysSQL("Foo'Bar\\"), '', true);
     }
 
     /**
@@ -869,7 +869,7 @@ public function testQuotesTableNameInListTableForeignKeysSQL()
      */
     public function testQuotesTableNameInListTableConstraintsSQL()
     {
-        self::assertContains("'Foo''Bar\\\\'", $this->_platform->getListTableConstraintsSQL("Foo'Bar\\"), '', true);
+        self::assertContains("'Foo''Bar\\'", $this->_platform->getListTableConstraintsSQL("Foo'Bar\\"), '', true);
     }
 
     /**
@@ -877,7 +877,7 @@ public function testQuotesTableNameInListTableConstraintsSQL()
      */
     public function testQuotesTableNameInListTableColumnsSQL()
     {
-        self::assertContains("'Foo''Bar\\\\'", $this->_platform->getListTableColumnsSQL("Foo'Bar\\"), '', true);
+        self::assertContains("'Foo''Bar\\'", $this->_platform->getListTableColumnsSQL("Foo'Bar\\"), '', true);
     }
 
     /**
@@ -885,6 +885,6 @@ public function testQuotesTableNameInListTableColumnsSQL()
      */
     public function testQuotesDatabaseNameInListTableColumnsSQL()
     {
-        self::assertContains("'Foo''Bar\\\\'", $this->_platform->getListTableColumnsSQL('foo_table', "Foo'Bar\\"), '', true);
+        self::assertContains("'Foo''Bar\\'", $this->_platform->getListTableColumnsSQL('foo_table', "Foo'Bar\\"), '', true);
     }
 }