org.apache.hadoop.mapreduce.lib.db (Hadoop 0.20.2-CDH3B4 API)
Date: 2011-02-21

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## Package org.apache.hadoop.mapreduce.lib.db

org.apache.hadoop.mapred.lib.db Package

See:
Description

Interface Summary
DBSplitter | DBSplitter will generate DBInputSplits to use with DataDrivenDBInputFormat.
DBWritable | Objects that are read from/written to a database should implement `DBWritable`.

Class Summary
BigDecimalSplitter | Implement DBSplitter over BigDecimal values.
BooleanSplitter | Implement DBSplitter over boolean values.
DataDrivenDBInputFormat<T extends DBWritable> | A InputFormat that reads input data from an SQL table.
DataDrivenDBInputFormat.DataDrivenDBInputSplit | A InputSplit that spans a set of rows
DataDrivenDBRecordReader<T extends DBWritable> | A RecordReader that reads records from a SQL table, using data-driven WHERE clause splits.
DateSplitter | Implement DBSplitter over date/time values.
DBConfiguration | A container for configuration property names for jobs with DB input/output.
DBInputFormat<T extends DBWritable> | A InputFormat that reads input data from an SQL table.
DBInputFormat.DBInputSplit | A InputSplit that spans a set of rows
DBInputFormat.NullDBWritable | A Class that does nothing, implementing DBWritable
DBOutputFormat<K extends DBWritable,V> | A OutputFormat that sends the reduce output to a SQL table.
DBRecordReader<T extends DBWritable> | A RecordReader that reads records from a SQL table.
FloatSplitter | Implement DBSplitter over floating-point values.
IntegerSplitter | Implement DBSplitter over integer values.
MySQLDataDrivenDBRecordReader<T extends DBWritable> | A RecordReader that reads records from a MySQL table via DataDrivenDBRecordReader
MySQLDBRecordReader<T extends DBWritable> | A RecordReader that reads records from a MySQL table.
OracleDataDrivenDBInputFormat<T extends DBWritable> | A InputFormat that reads input data from an SQL table in an Oracle db.
OracleDataDrivenDBRecordReader<T extends DBWritable> | A RecordReader that reads records from a Oracle table via DataDrivenDBRecordReader
OracleDateSplitter | Implement DBSplitter over date/time values returned by an Oracle db.
OracleDBRecordReader<T extends DBWritable> | A RecordReader that reads records from an Oracle SQL table.
TextSplitter | Implement DBSplitter over text strings.

## Package org.apache.hadoop.mapreduce.lib.db Description

## org.apache.hadoop.mapred.lib.db Package

This package contains a library to read records from a database as an input to a mapreduce job, and write the output records to the database.

The Database to access can be configured using the static methods in the DBConfiguration class. Jobs reading input from a database should use DBInputFormat#setInput() to set the configuration. And jobs writing its output to the database should use DBOutputFormat#setOutput().

Tuples from/to the database are converted to/from Java objects using DBWritable methods. Typically, for each table in the db, a class extending DBWritable is defined, which holds the fields of the tuple. The fields of a record are read from the database using DBWritable#readFields(ResultSet), and written to the database using DBWritable#write(PreparedStatament statement).

An example program using both DBInputFormat and DBOutputFormat can be found at src/examples/org/apache/hadoop/examples/DBCountPageview.java.

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