In the setInput(...) function in DBInputFormat, there are two sets of arguments that one can use.
1. public static void *setInput*(JobConf <http://hadoop.apache.org/core/docs/current/api/org/apache/hadoop/mapred/JobConf.html> job, Class <http://java.sun.com/javase/6/docs/api/java/lang/Class.html?is-external=true><? extends DBWritable <http://hadoop.apache.org/core/docs/current/api/org/apache/hadoop/mapred/lib/db/DBWritable.html>> inputClass, String <http://java.sun.com/javase/6/docs/api/java/lang/String.html?is-external=true> tableName, String <http://java.sun.com/javase/6/docs/api/java/lang/String.html?is-external=true> conditions, String <http://java.sun.com/javase/6/docs/api/java/lang/String.html?is-external=true> orderBy, String <http://java.sun.com/javase/6/docs/api/java/lang/String.html?is-external=true>... fieldNames) a) In this, do we necessarily have to give all the fieldNames (which are the column names right?) that the table has, or do we need to specify only the ones that we want to extract? b) Do we have to have a orderBy or not necessarily? Does this relate to the primary key in the table in any ways? 2. public static void *setInput*(JobConf <http://hadoop.apache.org/core/docs/current/api/org/apache/hadoop/mapred/JobConf.html> job, Class <http://java.sun.com/javase/6/docs/api/java/lang/Class.html?is-external=true><? extends DBWritable <http://hadoop.apache.org/core/docs/current/api/org/apache/hadoop/mapred/lib/db/DBWritable.html>> inputClass, String <http://java.sun.com/javase/6/docs/api/java/lang/String.html?is-external=true> inputQuery, String <http://java.sun.com/javase/6/docs/api/java/lang/String.html?is-external=true> inputCountQuery) a) Is there any restriction on the kind of queries that this function can take in the inputQuery string? I am facing issues in getting this to work with an Oracle database and have no idea of how to debug it (an email sent earlier). Can anyone give me some inputs on this please? Thanks -Amandeep Amandeep Khurana Computer Science Graduate Student University of California, Santa Cruz
