intellij idea hibernate - java.sql.SQLException: No database selected - intellij-idea

Question

i'm having trubble in executing an SQL command with in intellij idea with hibernate.
this is the code i wrote:
import models.Employee;
import org.hibernate.ejb.HibernatePersistence;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.spi.PersistenceProvider;
import java.util.HashMap;
import java.util.List;
public class manager {
public final static String SELECT_QUERY = new String("from Employee where id =:id");
public static void main(String[] args){
int id = 21577911;
PersistenceProvider pp = new HibernatePersistence();
EntityManagerFactory emf = pp.createEntityManagerFactory("NewPersistenceUnit", new HashMap());
EntityManager em = emf.createEntityManager();
List<Employee> employees = em.createQuery(SELECT_QUERY, Employee.class).setParameter("id", id).getResultList();
System.out.println(employees);
em.close();
}
}
and these are the errors:
Exception in thread "main" javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: could not extract ResultSet
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1387)
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1310)
at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:273)
at manager.main(manager.java:31)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)
Caused by: org.hibernate.exception.GenericJDBCException: could not extract ResultSet
at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:54)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:125)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:110)
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:61)
at org.hibernate.loader.Loader.getResultSet(Loader.java:2036)
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1836)
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1815)
at org.hibernate.loader.Loader.doQuery(Loader.java:899)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:341)
at org.hibernate.loader.Loader.doList(Loader.java:2522)
at org.hibernate.loader.Loader.doList(Loader.java:2508)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2338)
at org.hibernate.loader.Loader.list(Loader.java:2333)
at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:490)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:355)
at org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:195)
at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1269)
at org.hibernate.internal.QueryImpl.list(QueryImpl.java:101)
at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:264)
... 6 more
Caused by: java.sql.SQLException: **No database selected**
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1074)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4096)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4028)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2490)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2651)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2734)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2155)
at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:2322)
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:56)
... 21 more
i have configured the persistence.xml exactly as in the video demo in:
http://www.jetbrains.com/idea/features/jpa_hibernate.html

Answer 1

Apparently this occurs when your application does not know what database to use. to resolve this issue, you should change your database driver url from:
"URL"="jdbc:mysql://localhost:3306/"
to
"URL"="jdbc:mysql://localhost:3306/databasename"

Answer 2

I am using hibernate in EJBs
and exception occurred in glassfish
SQL Error: 1046, SQLState: 3D000
No database selected
i did checked in glassfish JDBC connection pool additional propteries
URL and url property was set like this
jdbc:mysql://localhost:3306/
fix is just added database name in url and URL property
jdbc:mysql://localhost:3306/{databasename}
and it worked f
error was