// raise error if we could not find the column
if (!fFoundColumn) {
throw new SemanticException(ErrorMsg.INVALID_COLUMN.getMsg(newCol.getName()));
}
AlterTableAlterPartDesc alterTblAlterPartDesc =
new AlterTableAlterPartDesc(SessionState.get().getCurrentDatabase(), tblName, newCol);
rootTasks.add(TaskFactory.get(new DDLWork(getInputs(), getOutputs(),
alterTblAlterPartDesc), conf));
}