diff --git a/src/Jfelder/OracleDB/Connectors/OracleConnector.php b/src/Jfelder/OracleDB/Connectors/OracleConnector.php
index 1f3673d..2b1eaf7 100644
--- a/src/Jfelder/OracleDB/Connectors/OracleConnector.php
+++ b/src/Jfelder/OracleDB/Connectors/OracleConnector.php
@@ -6,6 +6,7 @@
 use Illuminate\Database\Connectors\ConnectorInterface as ConnectorInterface;
 use InvalidArgumentException;
 use Jfelder\OracleDB\OCI_PDO\OCI as OCI;
+use PDO;
 
 class OracleConnector extends Connector implements ConnectorInterface
 {
@@ -15,9 +16,9 @@ class OracleConnector extends Connector implements ConnectorInterface
      * @var array
      */
     protected $options = [
-        \PDO::ATTR_CASE => \PDO::CASE_LOWER,
-        \PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION,
-        \PDO::ATTR_ORACLE_NULLS => \PDO::NULL_NATURAL,
+        PDO::ATTR_CASE => PDO::CASE_LOWER,
+        PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
+        PDO::ATTR_ORACLE_NULLS => PDO::NULL_NATURAL,
     ];
 
     /**
diff --git a/src/Jfelder/OracleDB/OracleConnection.php b/src/Jfelder/OracleDB/OracleConnection.php
index 37f91fd..0aaa686 100644
--- a/src/Jfelder/OracleDB/OracleConnection.php
+++ b/src/Jfelder/OracleDB/OracleConnection.php
@@ -2,12 +2,13 @@
 
 namespace Jfelder\OracleDB;
 
-use Doctrine\DBAL\Driver\OCI8\Driver as DoctrineDriver;
+use Exception;
 use Illuminate\Database\Connection;
-use Jfelder\OracleDB\Query\Grammars\OracleGrammar as QueryGrammer;
+use Jfelder\OracleDB\PDO\OracleDriver;
+use Jfelder\OracleDB\Query\Grammars\OracleGrammar as QueryGrammar;
 use Jfelder\OracleDB\Query\OracleBuilder as OracleQueryBuilder;
 use Jfelder\OracleDB\Query\Processors\OracleProcessor;
-use Jfelder\OracleDB\Schema\Grammars\OracleGrammar as SchemaGrammer;
+use Jfelder\OracleDB\Schema\Grammars\OracleGrammar as SchemaGrammar;
 use Jfelder\OracleDB\Schema\OracleBuilder as OracleSchemaBuilder;
 use PDO;
 
@@ -46,17 +47,21 @@ public function query()
      */
     protected function getDefaultQueryGrammar()
     {
-        return $this->withTablePrefix(new QueryGrammer);
+        ($grammar = new QueryGrammar)->setConnection($this);
+
+        return $this->withTablePrefix($grammar);
     }
 
     /**
      * Get the default schema grammar instance.
      *
-     * @return \Jfelder\OracleDB\Schema\Grammars\OracleGrammar
+     * @return \Jfelder\OracleDB\Schema\Grammars\OracleGrammar|null
      */
     protected function getDefaultSchemaGrammar()
     {
-        return $this->withTablePrefix(new SchemaGrammer);
+        ($grammar = new SchemaGrammar)->setConnection($this);
+
+        return $this->withTablePrefix($grammar);
     }
 
     /**
@@ -76,7 +81,7 @@ protected function getDefaultPostProcessor()
      */
     protected function getDoctrineDriver()
     {
-        return new DoctrineDriver;
+        return new OracleDriver;
     }
 
     /**
@@ -129,4 +134,14 @@ public function oracleInsertGetId($query, $bindings = [])
             return (int) $last_insert_id;
         });
     }
+
+    /**
+     * Determine if the given database exception was caused by a unique constraint violation.
+     *
+     * @return bool
+     */
+    protected function isUniqueConstraintError(Exception $exception)
+    {
+        return boolval(preg_match('#ORA-00001: unique constraint#i', $exception->getMessage()));
+    }
 }
diff --git a/src/Jfelder/OracleDB/OracleDBServiceProvider.php b/src/Jfelder/OracleDB/OracleDBServiceProvider.php
index 2a7a7ab..401ba19 100644
--- a/src/Jfelder/OracleDB/OracleDBServiceProvider.php
+++ b/src/Jfelder/OracleDB/OracleDBServiceProvider.php
@@ -46,9 +46,9 @@ public function register()
                 // setup connection resolver
                 Connection::resolverFor('oracle', function ($connection, $database, $prefix, $config) {
                     $oConnector = new OracleConnector();
-                    
+
                     $oConnection = $oConnector->connect($config);
-                    
+
                     return new OracleConnection($oConnection, $config['database'], $config['prefix'], $config);
                 });
             }
diff --git a/src/Jfelder/OracleDB/PDO/OracleDriver.php b/src/Jfelder/OracleDB/PDO/OracleDriver.php
new file mode 100644
index 0000000..ab8e1b2
--- /dev/null
+++ b/src/Jfelder/OracleDB/PDO/OracleDriver.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace Jfelder\OracleDB\PDO;
+
+use Doctrine\DBAL\Driver\AbstractOracleDriver;
+use Illuminate\Database\PDO\Concerns\ConnectsToDatabase;
+
+class OracleDriver extends AbstractOracleDriver
+{
+    use ConnectsToDatabase;
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getName()
+    {
+        return 'oci8';
+    }
+}
diff --git a/src/Jfelder/OracleDB/Query/OracleBuilder.php b/src/Jfelder/OracleDB/Query/OracleBuilder.php
index 9ef39e2..ebf449d 100644
--- a/src/Jfelder/OracleDB/Query/OracleBuilder.php
+++ b/src/Jfelder/OracleDB/Query/OracleBuilder.php
@@ -2,9 +2,10 @@
 
 namespace Jfelder\OracleDB\Query;
 
+use Illuminate\Database\Query\Builder;
 use Illuminate\Database\Query\Expression;
 
-class OracleBuilder extends \Illuminate\Database\Query\Builder
+class OracleBuilder extends Builder
 {
     /**
      * Add a subquery cross join to the query.