[DBAL-407] Implement error detection on foreign key constraint exception for mysql and sqlite

lib/Doctrine/DBAL/DBALException.php

@@ -24,6 +24,7 @@ class DBALException extends \Exception
     const ERROR_DUPLICATE_KEY = 1;
     const ERROR_UNKNOWN_TABLE = 2;
     const ERROR_TABLE_ALREADY_EXISTS = 3;
+    const ERROR_FOREIGN_KEY_CONSTRAINT = 4;
 
     /**
      * @param string $method

lib/Doctrine/DBAL/Driver/PDOMySql/Driver.php

@@ -117,6 +117,10 @@ class Driver implements \Doctrine\DBAL\Driver
     {
         switch ($exception->getCode()) {
             case 23000:
+                if (strpos($exception->getMessage(), 'Cannot delete or update a parent row: a foreign key constraint fails') !== false) {
+                    return DBALException::ERROR_FOREIGN_KEY_CONSTRAINT;
+                }
+
                 return DBALException::ERROR_DUPLICATE_KEY;
             case '42S02':
                 return DBALException::ERROR_UNKNOWN_TABLE;

tests/Doctrine/Tests/DBAL/Functional/ExceptionTest.php

@@ -34,7 +34,7 @@ class ExceptionTest extends \Doctrine\Tests\DbalFunctionalTestCase
 
     public function testTableAlreadyExists()
     {
-        $table = new \Doctrine\DBAL\Schema\Table("duplicatekey_table");
+        $table = new \Doctrine\DBAL\Schema\Table("alreadyexist_table");
         $table->addColumn('id', 'integer', array());
         $table->setPrimaryKey(array('id'));
 
@@ -46,5 +46,34 @@ class ExceptionTest extends \Doctrine\Tests\DbalFunctionalTestCase
             $this->_conn->executeQuery($sql);
         }
     }
+
+    public function testForeignKeyContraintException()
+    {
+        if ( ! $this->_conn->getDatabasePlatform()->supportsForeignKeyConstraints()) {
+            $this->markTestSkipped("Only fails on platforms with foreign key constraints.");
+        }
+
+        $schema = new \Doctrine\DBAL\Schema\Schema();
+        $table = $schema->createTable("constraint_error_table");
+        $table->addColumn('id', 'integer', array());
+        $table->setPrimaryKey(array('id'));
+
+        $owningTable = $schema->createTable("owning_table");
+        $owningTable->addColumn('id', 'integer', array());
+        $owningTable->addColumn('constraint_id', 'integer', array());
+        $owningTable->setPrimaryKey(array('id'));
+        $owningTable->addForeignKeyConstraint($table, array('constraint_id'), array('id'));
+
+        foreach ($schema->toSql($this->_conn->getDatabasePlatform()) AS $sql) {
+            $this->_conn->executeQuery($sql);
+        }
+
+        $this->_conn->insert("constraint_error_table", array('id' => 1));
+        $this->_conn->insert("owning_table", array('id' => 1, 'constraint_id' => 1));
+
+        $this->setExpectedException('\Doctrine\DBAL\DBALException', null, DBALException::ERROR_FOREIGN_KEY_CONSTRAINT);
+        $this->_conn->delete('constraint_error_table', array('id' => 1));
+
+    }
 }
  
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