public String createUpdateAgainstExistingSchema(
      URL schema, String jdbcUrl, String userName, String password, URL indexNames)
      throws Exception {
    final DatabaseSnapshot reference = createFromCommittedSchema(schema, indexNames);
    final DatabaseSnapshot target =
        LiquibaseModelFactory.readSnapshotFromDatabase(jdbcUrl, userName, password);

    final StringBuilder sb = new StringBuilder();
    printChanges(reference, target, sb);
    return sb.toString();
  }
 public String createDropAgainstExistingSchema(Connection connection) throws Exception {
   return createDropAgainstExistingSchema(
       LiquibaseModelFactory.readSnapshotFromDatabase(connection));
 }
 public String createDropAgainstExistingSchema(String jdbcUrl, String userName, String password)
     throws Exception {
   return createDropAgainstExistingSchema(
       LiquibaseModelFactory.readSnapshotFromDatabase(jdbcUrl, userName, password));
 }