Create database with JPA?

Question

When I create (using JPA - java persistence api) a persistence unit and then persistence entities they auto create the corresponding tables and fields in the database.

Answer 1

The database has to be created manually (Fortunatly you didn't ask why ;-). Which is similar to the user/password combination you use to connect to your database server, which must already exist in order to connect to the DB.

Answer 2

My solution to this problem was to add the following right before I create my entity manager:

  Connection connection =
      DriverManager.getConnection("jdbc:mysql://localhost/?user=" + DB_USER);
  Statement stmt = connection.createStatement();
  stmt.executeUpdate("CREATE DATABASE IF NOT EXISTS " + DB_NAME);

You'll need to either surround that with a try/catch block or add a throws SQLException notation to the function in which it exists. So, for example, here is my initEntityManager function:

public static void initEntityManager() throws SQLException {
    Connection connection =
        DriverManager.getConnection("jdbc:mysql://localhost/?user=" + DB_USER);
    Statement stmt = connection.createStatement();
    stmt.executeUpdate("CREATE DATABASE IF NOT EXISTS " + DB_NAME);
    emf = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT_NAME);
    em = emf.createEntityManager();
}