"Unknown database 'mydb' " error with jpa

Question

hello, i'm trying to connect to mysql server but get this error. when mydb is the only name in the system. please tell me where i'm wrong...

my persistence xml is as folow:

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
    http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
 version="1.0">

 <persistence-unit name="MyPersistenceUnit">

  <provider>org.hibernate.ejb.HibernatePersistence</provider>

  <properties>
   <property name="hibernate.archive.autodetection" value="class" />
   <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver" />
   <property name="hibernate.connection.url" value="jdbc:mysql://localhost:3306/mydb" />
   <property name="hibernate.connection.username" value="root" />
   <property name="hibernate.connection.password" value="tft" />
   <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />

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

   <property name="hibernate.show_sql" value="true" />
   <property name="hibernate.format_sql" value="true" />
   <property name="hibernate.use_sql_comments" value="true" />
  </properties>

 </persistence-unit>
</persistence>