1 / 9

Tree-based Indexing

Tree-based Indexing. Hessam Zakerzadeh. ISAM ( Indexed Sequential Access Method ). Static index structure. Effective when file is not frequently updated. Data values reside in leaf nodes. Overflow . page. Non-leaf. Pages. Leaf. Pages. Primary pages. Leaf pages contain data entries .

mura
Télécharger la présentation

Tree-based Indexing

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Tree-based Indexing HessamZakerzadeh

  2. ISAM(Indexed Sequential Access Method) • Static index structure. • Effective when file is not frequently updated. • Data values reside in leaf nodes.

  3. Overflow page Non-leaf Pages Leaf Pages Primary pages • Leaf pages contain data entries.

  4. After Inserting 23*, 48*, 41*, 42* ... Root 40 Index Pages 51 63 20 33 Primary Leaf 10* 15* 20* 27* 46* 55* 40* 51* 97* 33* 37* 63* Pages 41* 48* 23* Overflow Pages 42*

  5. Give an example of when you would use each element (A or B) for each of the following ‘A versus B’ pairs: • A hashed index using Alternative (1) versus heap file organization. • hashed index : when most of the queries are equality queries. • heap file : when a file is scanned in sequential order.

  6. Extendible Hashing versus Linear Hashing. • Extendible Hashing : When data values lead to a skewed distribution • Linear Hashing : A large data file requiring a directory to span several pages.

  7. Static Hashing versus Linear Hashing. • Static Hashing :When the number of values are constant and values are of form 2^n+k for various values of n and few values of k. Linear hashing becomes very skewed. • Linear Hashing: When number of records varies, and hash key values are uniformly distributed.

  8. Static Hashing versus ISAM • Static Hashing: When the number records are constant and most of the queries are equality search • ISAM:When queries involve range queries

  9. Linear Hashing versus B+ trees • Linear Hashing :When queries are equality search • B+ trees :When queries are range search

More Related