--- /dev/null
+<?php
+
+/*
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This software consists of voluntary contributions made by many individuals
+ * and is licensed under the MIT license. For more information, see
+ * <http://www.doctrine-project.org>.
+ */
+
+namespace Doctrine\ORM\Mapping;
+
+/**
+ * Naming strategy implementing the underscore naming convention.
+ * Converts 'MyEntity' to 'my_entity' or 'MY_ENTITY'.
+ *
+ *
+ * @link www.doctrine-project.org
+ * @since 2.3
+ * @author Fabio B. Silva <fabio.bat.silva@gmail.com>
+ */
+class UnderscoreNamingStrategy implements NamingStrategy
+{
+ /**
+ * @var integer
+ */
+ private $case;
+
+ /**
+ * Underscore naming strategy construct
+ *
+ * @param integer $case CASE_LOWER | CASE_UPPER
+ */
+ public function __construct($case = CASE_LOWER)
+ {
+ $this->case = $case;
+ }
+
+ /**
+ * @return integer
+ */
+ public function getCase()
+ {
+ return $this->case;
+ }
+
+ /**
+ * Sets string case CASE_LOWER | CASE_UPPER
+ * Alphabetic characters converted to lowercase or uppercase
+ *
+ * @param integer $case
+ */
+ public function setCase($case)
+ {
+ $this->case = $case;
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function classToTableName($className)
+ {
+ if (strpos($className, '\\') !== false) {
+ $className = substr($className, strrpos($className, '\\') + 1);
+ }
+
+ return $this->underscore($className);
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function propertyToColumnName($propertyName)
+ {
+ return $this->underscore($propertyName);
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function referenceColumnName()
+ {
+ return $this->case === CASE_UPPER ? 'ID' : 'id';
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function joinColumnName($propertyName)
+ {
+ return $this->underscore($propertyName) . '_' . $this->referenceColumnName();
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function joinTableName($sourceEntity, $targetEntity, $propertyName = null)
+ {
+ return $this->classToTableName($sourceEntity) . '_' . $this->classToTableName($targetEntity);
+ }
+
+ /**
+ * {@inheritdoc}
+ */
+ public function joinKeyColumnName($entityName, $referencedColumnName = null)
+ {
+ return $this->classToTableName($entityName) . '_' .
+ ($referencedColumnName ?: $this->referenceColumnName());
+ }
+
+ /**
+ * @param string $string
+ * @return string
+ */
+ private function underscore($string)
+ {
+ $string = preg_replace('/(?<=[a-z])([A-Z])/', '_$1', $string);
+
+ if ($this->case === CASE_UPPER) {
+ return strtoupper($string);
+ }
+
+ return strtolower($string);
+ }
+}