rwsch.put(alias, part_col.getName(),
new ColumnInfo(part_col.getName(), TypeInfoFactory.stringTypeInfo, alias, true));
}
// Create the root of the operator tree
top = putOpInsertMap(OperatorFactory.get(new tableScanDesc(alias), new RowSchema(rwsch.getColumnInfos())), rwsch);
// Add this to the list of top operators - we always start from a table scan
this.topOps.put(alias_id, top);
// Add a mapping from the table scan operator to Table