以编程方式创建模式时获取未知的数据库异常？

Question

我正在尝试使用hibernate/GWT/Java以编程方式创建模式和表。我创建了所有的映射资源和属性等的配置如下，

Configuration hibConfiguration = new Configuration().configure(configFileDoc); 

，但是，当我说

SchemaExport schemaExport = new SchemaExport(hibConfiguration); 
schemaExport.create(true, true); 

它抛出异常，因为，

ERROR: HHH000231: Schema export unsuccessful 

    com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown database 'testschema' 
     at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 
     at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) 
     at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) 
     at java.lang.reflect.Constructor.newInstance(Constructor.java:513) 
     at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) 
     at com.mysql.jdbc.Util.getInstance(Util.java:386) 
     at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1052) 
     at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3609) 
     at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3541) 
     at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:943) 
     at com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:4113) 
     at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1308) 
     at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2336) 
     at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2369) 
     at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2153) 
     at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:792) 
     at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47) 
     at sun.reflect.GeneratedConstructorAccessor36.newInstance(Unknown Source) 
     at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) 
     at java.lang.reflect.Constructor.newInstance(Constructor.java:513) 
     at com.mysql.jdbc.Util.handleNewInstance(Util.java:411) 
     at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:381) 
     at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:305) 
     at java.sql.DriverManager.getConnection(DriverManager.java:582) 
     at java.sql.DriverManager.getConnection(DriverManager.java:154) 
     at org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.getConnection(DriverManagerConnectionProviderImpl.java:193) 
     at org.hibernate.tool.hbm2ddl.ManagedProviderConnectionHelper.prepare(ManagedProviderConnectionHelper.java:55) 
     at org.hibernate.tool.hbm2ddl.DatabaseExporter.<init>(DatabaseExporter.java:52) 
     at org.hibernate.tool.hbm2ddl.SchemaExport.execute(SchemaExport.java:367) 
     at org.hibernate.tool.hbm2ddl.SchemaExport.create(SchemaExport.java:304) 
     at org.hibernate.tool.hbm2ddl.SchemaExport.create(SchemaExport.java:293) 

我cfg.xml中文件：

<?xml version="1.0" encoding="UTF-8" standalone="no"?> 
<hibernate-configuration> 
    <session-factory> 
     <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> 
     <property name="hibernate.connection.password">passwd</property> 
     <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> 
     <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/testSchema</property> 
     <property name="hibernate.connection.username">root</property> 
     <property name="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property> 
     <property name="javax.persistence.validation.mode">none</property> 
     <property name="hibernate.temp.use_jdbc_metadata_defaults">false</property> 
     <property name="hibernate.default_entity_mode">dynamic-map</property> 
     <property name="hibernate.hbm2ddl.auto">create</property> 
    </session-factory> 
</hibernate-configuration> 

如果我手动创建了模式，那么它工作正常，即创建表和列也。但通常它不会创建模式，是不是可以自动创建模式？

Answer 1

Hibernate不会动态创建的模式...你必须手动创建它。我使用简单的JDBC连接和语句来创建模式，然后SchemaExport将执行生成表和字段的工作。所以没有办法用hibernate创建实际的模式。你必须手动创建它。

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); 
DocumentBuilder builder = factory.newDocumentBuilder(); 
Document configFileDoc = builder.parse(new ByteArrayInputStream(configFileStr.getBytes())); 

Configuration hibConfiguration = new Configuration(); 
hibConfiguration.configure(configFileDoc); 
ArrayList<Document> hbmFileDocs = getHBMFileDocList(); //created the documents of the file string 
for(Document doc : hbmFileDocs) 
     hibConfiguration.addDocument(doc); 

hibConfiguration.buildMappings(); 
Class.forName("com.mysql.jdbc.Driver"); 
conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/", "username", "password"); 
stmt = conn.createStatement(); 
String sql = "CREATE DATABASE "+schemaName; 
stmt.executeUpdate(sql); 
SchemaExport schemaExport = new SchemaExport(hibConfiguration); 
schemaExport.create(true, true); 

这将生成完整的模式，它为我工作。

Answer 2

您需要添加更多的特性在Hibernate的配置文件，来自动创建数据库/模式：

<property name="hibernate.hbm2ddl.auto">create</property> 

Answer 3

我猜hibernate只有在情况下创建模式的创建database。您需要手动创建数据库testschema。

手动创建数据库testschema然后启动您的hibernate应用程序。

Answer 4

可以自动创建模式。下面的属性添加到您的Hibernate XML配置：

<property name="hibernate.hbm2ddl.auto">update</property> 

OR

<prop key="hibernate.hbm2ddl.auto">update</prop> 

按照上面的属性，如果它不存在，Hibernate将只创建数据库，并且将更新任何现有的表格以匹配您当前的域模型。

另一种选择将是这样的：

<property name="hibernate.hbm2ddl.auto">create-drop</property> 

上述性质意味着，Hibernate会在每次启动应用程序

更新时间打造一个全新的数据库：有用的网址

http://manikandanmv.wordpress.com/2011/04/13/hibernate-basics-simple-example/

http://khartig.wordpress.com/2008/12/20/dynamic-schema-and-database-creation-with-netbeans-hibernate-and-ejb3/

http://blog.sencide.com/2011/03/hibernate-tutorial-for-beginners.html

http://www.jroller.com/eyallupu/entry/hibernate_s_hbm2ddl_tool

http://hannelita.wordpress.com/2012/03/21/hibernate-cfg-hibernate-4-0-0/