• Post Reply Bookmark Topic Watch Topic
  • New Topic
programming forums Java Mobile Certification Databases Caching Books Engineering Micro Controllers OS Languages Paradigms IDEs Build Tools Frameworks Application Servers Open Source This Site Careers Other all forums
this forum made possible by our volunteer staff, including ...
Marshals:
  • Campbell Ritchie
  • Paul Clapham
  • Jeanne Boyarsky
  • Junilu Lacar
  • Henry Wong
Sheriffs:
  • Ron McLeod
  • Devaka Cooray
  • Tim Cooke
Saloon Keepers:
  • Tim Moores
  • Stephan van Hulst
  • Frits Walraven
  • Tim Holloway
  • Carey Brown
Bartenders:
  • Piet Souris
  • salvin francis
  • fred rosenberger

indexes

 
Ranch Hand
Posts: 129
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Please explain how does the index work in database?
 
Bartender
Posts: 1847
14
Eclipse IDE Spring Java
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
The index in a database works in the same way an index would work in a book. It's a way for the DB to retrieve data faster.

In Oracle you can make your own indexes for columns you use a lot, but some are made automatically for columns with Primary Key constraints or Unique constraints.
 
anish jain
Ranch Hand
Posts: 129
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

Janeice DelVecchio wrote:The index in a database works in the same way an index would work in a book. It's a way for the DB to retrieve data faster.

In Oracle you can make your own indexes for columns you use a lot, but some are made automatically for columns with Primary Key constraints or Unique constraints.



Can you please elaborate? I want to know how does that work when someone fires a select query?
 
Rancher
Posts: 618
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

Can you please elaborate? I want to know how does that work when someone fires a select query?



Every database implementation is different. Here's a link that explains how Oracle database does it: http://www.dba-oracle.com/art_9i_indexing.htm
 
There is no "i" in denial. Tiny ad:
Devious Experiments for a Truly Passive Greenhouse!
https://www.kickstarter.com/projects/paulwheaton/greenhouse-1
    Bookmark Topic Watch Topic
  • New Topic