Add SpringNamingStrategy to improve FK names

Add a new `SpringNamingStrategy` hibernate `NamingStrategy` that
extends `ImprovedNamingStrategy` to improve the name of foreign
key columns.

Fixes gh-213

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaAutoConfiguration.java

@@ -21,7 +21,6 @@ import java.util.Map;
 import javax.persistence.EntityManager;
 import javax.sql.DataSource;
 
-import org.hibernate.cfg.ImprovedNamingStrategy;
 import org.hibernate.ejb.HibernateEntityManager;
 import org.springframework.beans.factory.BeanClassLoaderAware;
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
@@ -31,6 +30,7 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
 import org.springframework.boot.autoconfigure.jdbc.EmbeddedDatabaseConnection;
 import org.springframework.boot.bind.RelaxedPropertyResolver;
+import org.springframework.boot.orm.jpa.SpringNamingStrategy;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.env.Environment;
 import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
@@ -83,7 +83,7 @@ public class HibernateJpaAutoConfiguration extends JpaBaseConfiguration implemen
 			LocalContainerEntityManagerFactoryBean entityManagerFactoryBean) {
 		Map<String, Object> properties = entityManagerFactoryBean.getJpaPropertyMap();
 		properties.put("hibernate.ejb.naming_strategy", this.environment.getProperty(
-				"naming-strategy", ImprovedNamingStrategy.class.getName()));
+				"naming-strategy", SpringNamingStrategy.class.getName()));
 		String ddlAuto = this.environment.getProperty("ddl-auto", getDefaultDdlAuto());
 		if (!"none".equals(ddlAuto)) {
 			properties.put("hibernate.hbm2ddl.auto", ddlAuto);

spring-boot/pom.xml

@@ -64,6 +64,11 @@
 			<artifactId>jetty-util</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>org.hibernate</groupId>
+			<artifactId>hibernate-entitymanager</artifactId>
+			<optional>true</optional>
+		</dependency>
 		<dependency>
 			<groupId>org.hibernate</groupId>
 			<artifactId>hibernate-validator</artifactId>

spring-boot/src/main/java/org/springframework/boot/orm/jpa/SpringNamingStrategy.java

+/*
+ * Copyright 2012-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.orm.jpa;
+
+import org.hibernate.cfg.ImprovedNamingStrategy;
+import org.hibernate.cfg.NamingStrategy;
+import org.hibernate.internal.util.StringHelper;
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+/**
+ * Hibernate {@link NamingStrategy} that follows Spring recommended naming conventions.
+ * Naming conventions implemented here are identical to {@link ImprovedNamingStrategy}
+ * with the exception that foreign key columns include the referenced column name.
+ * 
+ * @author Phillip Webb
+ * @see "http://stackoverflow.com/questions/7689206/ejb3namingstrategy-vs-improvednamingstrategy-foreign-key-naming"
+ */
+public class SpringNamingStrategy extends ImprovedNamingStrategy {
+
+	@Override
+	public String foreignKeyColumnName(String propertyName, String propertyEntityName,
+			String propertyTableName, String referencedColumnName) {
+		String name = propertyTableName;
+		if (propertyName != null) {
+			name = StringHelper.unqualify(propertyName);
+		}
+		Assert.state(StringUtils.hasLength(name),
+				"Unable to generate foreignKeyColumnName");
+		return columnName(name) + "_" + referencedColumnName;
+	}
+
+}