Mappings and datatypes

• ElasticSearch is schema less, i.e. we can store documents with any number of fields and types of fields.
• There are always some set of fields common across all documents in a type.
• Core Data Types
  • String Data types
    • text: The text datatype is useful for supporting full-text search for fields that contain a description or lenghty text values. Thes fields are analyzed before indexing to support full-text search
    • keyword: This type enable analytics on string fields. Fields of this type support sorting, filtering and aggregations
  • Numeric data types:
    • byte, short, integer and long
    • float and double
    • half_float
    • scaled_float
  • Date datatype:
    • data: Date with an optional timestamp
  • Boolean datatype:
    • boolean:
  • Binary datatype:
    • binary: Allows us to store binary with Base64 encoding
  • Range datatypes:
    • integer_range, float_range, long_range, double_range, data_range
• Complex Data types:
  • Array datatype:
  • Object data types:
  • Nested data type:
• Other datatypes:
  • Geo-point datatype
  • Geo-shape datatype
  • IP datatype

Understanding Mapping

• In the last session we have inserted a data to the index qualitythought
  
  

Inverted Indexes

• Consider we have the following documents with text inserted into elastic search

Document ID	Document
1	Its Friday tomorrow
2	Friday night is beginining of Weekend
3	The best day of the week is your choice
4	This week is best for sales

• Elastic search builds a data structure from the three documents that have been indexed. This data structure is called as inverted index
• Documents will be broken down into terms after removing puncutation and placing them in LowerCase
• Terms are sorted alphabetically
  
• When searching for terms in the documents, it is blazingly fast to locate the document in which given terms appear.

CRUD Operations

• To understand how to perform CRUD Operations, we will look into following APIs under document API
• Index API
• Get API
• Update API
• Delete API

Index API

• Adding a document to a type within an index of elastic search is called as indexing.
• There are two ways to index a document
• Indexing a document by providing an ID
  
• Indexing a document by without providing an ID
  

Get API

• This API is used to retrieve documents
  
  

Update API

• This is used to update a document.
  
  

Delete API