Talk:Index (database)

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Want to help? Here are some suggestions for improving this article:

  1. Merge "Bitmap Index" and "Dense Index" into this article (please post comments by 5/19/2007)
  2. Expand discussion of database physical indexing (B-tree, B+ tree, hash tables, etc.) and examples of products that use each type
  3. Expanded discussion of nonclustered versus clustered indexes
  4. Discussion of index impact on query and other operation performance
  5. Discussion of "covering" index
  6. Discussion of index strategies from other databases (i.e., xBase, Random Access Files, XML indexing)
  7. Consider adding graphics where appropriate (possibly images of index structures?)
  8. Indicate advantages and disadvantages of indexes; help in understanding the concept's relevancy

Contents

[edit] Proposed move

I propose this page be moved to "Database index", to avoid the awkward parenthesized subject and because this is a familiar enough unambiguous term. Consent/dissent? Deco 22:18, 9 August 2005 (UTC)

I disagree. Index is an appropriate name for the page, just as "Query (database)" would be for a DB query. I rarely refer to a database index by the term "Database Index", I just call it an index. --Rob 20:02, 26 October 2005 (UTC)
Also disagree. Awkward parenthesized subjects are a way of life here at Wikpedia. :) Turnstep 23:21, 26 October 2005 (UTC)

[edit] Expert tag

Ok I'm an expert, what is wrong with this article? I'm going to remove the expert tag and I hope that anyone who puts it back can leave a note as to what is wrong so it can be corrected. Triddle 14:07, 8 October 2005 (UTC)

Hi expert, this is the non-expert. Frankly, the text is too poor (even for me). The email example is too specific of a certain implementation and a fulltext index could solve the problem. Also, it doesn't say anything about multiple indexes, binary indexes, etc. I'm sure there are more index types with different behaviors, but, again, I’m not an expert, so I don't know. :)
Thanks for the comments, those are all good observations. For reference a more proper tag is {{expand}}. I do have one rebuttal though, hopefully if someone comes along to expand this article they can integrate some of this info. First, I don't think the performance of a full-text index is going to match the performance of the reverse trick; add to that the fact that not all databases support full-text indexing out of the box and this trick is pretty useful. Thanks for the comments, I'm sure they will come in useful in the future. Triddle 01:20, 10 October 2005 (UTC)

[edit] Suggested additions for expansion

(Can you tell I've had more than a few questions about these lately?)

  1. SQL Standard Examples, or even pseudocode.
  2. Effects of indices on standard SQL operations, not just select.
  3. Implementations of indices on various database systems

Dunno if I inadvertently missed some of these topics. --Rob 23:35, 26 October 2005 (UTC)

May I also suggest that we at least mention the reason for using'indexes' vs. 'indices'. Though perhaps a minor linguistics/usage distinction, it comes up in IT dept. discussions and matters for things like keyword searches. Rob uses 'indices' in this discussion area, for example, but the entry itself always uses 'indexes'. -- jorvis

  • JA: The disambig page for Index gives the standard usage for the two different plurals. Probably this page needs to be brought into line with that. Jon Awbrey 14:58, 15 March 2006 (UTC)
  • JA: Oops, that's what I get for trying to work before coffee, I thought the article was using "index" as a synonym for "key". It now seems to be using it for a separate table data structure containing keys (= indices), like an index at the back of a book, in which case "indexes" is correct. Jon Awbrey 15:08, 15 March 2006 (UTC)

[edit] Merge suggestion - from 'Bitmap index'

The current content of Bitmap index is sparse and much of the page space is occupied by an illustrative data grid. The content would/could appropriately sit as a section of this article; if expansion takes place, Template:main could be used to cross-reference, a solution I prefer over a bare see-also link (currently included here). --User:Ceyockey (talk to me) 19:01, 21 December 2006 (UTC)

If no objections by Saturday, 5/19/2007, I will merge Bitmap index into this article. SqlPac 04:07, 17 May 2007 (UTC)
Bitmap Index deserves to have its own pages. User:oaf2 May 26 2007

[edit] Merge suggestion - from 'Dense index'

The article dense index was created earlier today (21 Dec) and is not wikified or categorized. It seems that the content would make a reasonable section in this article, better than a stand alone stub article awaiting clean-up. Regards --User:Ceyockey (talk to me) 19:04, 21 December 2006 (UTC)

yes, it'll be nice to merge the dense index and sparse index into this one. we could also add a picture like this one : http://www.e-student.si/data/thumb/6/69/Indeksi_gostota.png/500px-Indeksi_gostota.png to ilusstrate the meaning of both. Stdazi 14:32, 15 April 2007 (UTC)

If no objections by Saturday, 5/19/2007, I will merge Bitmap index into this article. SqlPac 04:07, 17 May 2007 (UTC)

[edit] Structure

I'm a bit disappointed that this article contains no information on the actual structure and implementation of database indexes, which is a deep but accessible subject. I'll look at adding this unless it's hiding someplace else. Dcoetzee 20:13, 11 May 2007 (UTC)

Excellent suggestion. I know that SQL Server uses B-Tree (or is it B+ Tree?) nonclustered indexes. A discussion of clustered vs. nonclustered indexes, and even so-called "covering indexes", would be appropriate as well. SqlPac 04:07, 17 May 2007 (UTC)