anchor.diff:  As explained in the previous sections, {eh} integrates closely with the Hadoop ecosystem and perform close introspection of the type information so that the data flow between {es} and Hadoop is as transparent as possible.
   This section takes a closer look at how the type conversion takes place and how data is mapped between the two systems.
   
  +[float]
   === Converting data to {es}
   
   By design, {eh} provides no data transformation or mapping layer itself simply because there is no need for them: Hadoop is designed to do ETL and some libraries (like Pig and Hive) provide type information themselves; further more {es} has rich support for mapping out of the box including automatic detection,  dynamic/schema-less mapping, templates and full manual control. 
  
positive.code: Instead of 'reinventing the wheel' and replicating functionality, {eh} focuses on what is missing by recognizing and leveraging existing features. 
  ////
  
  [[mapping-date]]
  === Time/Date mapping
  
  When it comes to handling dates, {es} always uses the http://en.wikipedia.org/wiki/ISO_8601[ISO 8601] format for date/time. This is the default date format of {es} - if a custom one is needed, please *add* it to the default option rather then just replacing it. See the {ref}/mapping-date-format.html[date format] section in {eh} reference documentation for more information.
  
  === Automatic mapping
  
  By default, {es} provides {ref}/docs-index_.html[automatic index and mapping] when data is added under an index that has not been created before. In other words, data can be added into {es} without the index and the mappings being defined a priori. This is quite convenient since {es} automatically adapts to the data being fed to it - moreover, if certain entries have extra fields, {es} schema-less nature allows them to be indexed without any issues.
  
negative.code: 
  Only if the defaults need to be overridden and/or if you experience the problems exposed below, consider using <<explicit-mapping>>.
  
  [float]
  ==== Disabling automatic mapping
  
  {es} allows 'automatic index creation' as well as 'dynamic mapping' (for extra fields present in documents) to be disabled through the `action.auto_create_index` and `index.mapper.dynamic` settings on the nodes config files. As a safety net, {eh} provides a dedicated configuration <<configuration-options-index,option>> `es.index.auto.create` which allows {eh} to either create the index or not without having to modify the {es} cluster options.
  
  [float]
  [[explicit-mapping]]
  === Explicit mapping
  
  