Hadoop MapReduce programmers often find that it is more convenient and productive to have direct access from their MapReduce programs to data stored in a RDBMS such as Teradata Enterprise Data Warehouse (EDW) because:

1. There is no benefit to exporting relational data into a flat file.
2. There is no need to upload the file into the Hadoop Distributed File System (HDFS).
3. There is no need to change and rerun the scripts/commands in the first two steps when they need to use different tables/columns in their MapReduce programs.