A data processing apparatus according to one or more embodiments may process metadata indicative of an attribute of real data input into an extract, transform, and load (ETL) tool external to the data processing apparatus. The real data and the metadata may each include an identification (ID). The data processing apparatus may include a memory and a processor. The memory may store a program. The processor may execute the program. The program may cause the processor to process the metadata to include the same ID as the real data output from the ETL tool.