File Structures N F. Chapter 1-1. z M.Folk and B.Zoellick, File Structures, Addison Wesley.

Transcription

1 File Structures žöof ú êëov f Ž N F z M.Folk and B.Zoellick, File Structures, Addison Wesley. z E. Horowitz, S. Sahni, and S. Anderson-Freed, Fundamentals of Data Structures in C, Computer Science Press. Chapter 1-1 Chapter 1-1

2 N Ÿ z File Structures + Advanced Data Structures File Ž N F FileN ö Ó, I/O Processing, Access Method External Sorting Indexing Hashing, Heap Structures Search Structures: AVL Tree, 2-3 Trees, B-Tree, z Not Includes Dynamic Programming, Divide-And-Conquer NP-Hard and NP-Complete Problems, Chapter 1-2 N ªŸ 1 r Ž N :Š' 9 IndexingN F 2 File System Call 10 AVL Tree, 2-3, Storage Device 11 Red-Black Tree, B-Tree (1) 4 Buffering, Blocking 12 B-Tree (2) 5 Field, Record, Page 13 B-Tree (3) 6 External Sorting(1) 14 Hashing (1) 7 8 External Sorting(2) ú ÒÎ Hashing (2) &Æ ÒÎ Chapter 1-3 Chapter 1-2

3 Chapter 1 Introduction to File Structures Chapter The Heart of File Structure Design z Motivation Disks are slow. RAM ļ : 120 nanoseconds Disk ļ : 10 ~ 30 milliseconds DiskN Enormous capacity at much less cost than RAM Non-volatile storage device z Goal Accessing to all the capacity without making our applications spend a lot of time waiting for the disk Chapter 1-5 Chapter 1-3

4 2. A Short History of File Structure Design z General goal of research in file structures One access to the disk. Ideal Only two or three trips to the disk. Practical Grouping information for fewer trips W File N ãï' ( File ªŸ /6 b&n J ) Chapter 1-6 z History Sequential file in tape device Direct access of disk using index Simple index ( sequentially stored ) Tree structured index Binary search tree, AVL tree B-tree, B + -tree: log k N access Hashing Extendible, dynamic hashing Multi-key access method Spatial access method: R-tree, K-D-B tree Chapter 1-7 Chapter 1-4

5 3. A Conceptual Toolkit: File Structure Literacy z File structure r b'nšf ŸŠ FÚ Sequential Access Method Indexed Sequential Access Method Direct Access Method z Disk I/O r új& új ŸŠ FÚ Buffering Blocking Bucket Concept Splitting & Merging Chapter 1-8 z ò TN FÚ: :újj ¾Rª GŸ zræ RŸV ~Š & &j Ÿ package ÚN Ÿ ^ Chapter 1-9 Chapter 1-5

6 4. fj Jr {N z ¾š& Jr b fj þjòr ö Ö ~Š Jr ÿâ ¾š&, Ö ¾š& z N Jr ¾š& JrÆ Ÿ ³, ³{, þjò ö ¾š& JrÆ rú Ÿ z Bj Jr ¾š& JrÚúÆ ë«š fj ö &«ëú þs Chapter 1-10 z êö Jr Ÿ Æ V Ÿ 2R ' Jr š, Æâ š, úª ¾š& Jr š Šs êö z ª Jr ê ª Æ ö ê â^ {, ³{,, ¾š& þjò {, Ž, Æâ N þjò z j Jr ¾š&/ N/ª Jr çæ ör '» Jr ÒšR Ö Ò ëbv Ÿ 2R Ÿ Chapter 1-11 Chapter 1-6

7 2~ JÒ 2~ ªŸ 2~ öÿ [î² 1.1] þ Bj Jr 2~ JÒ ú Ö ò. Šb Ó [î² 1.2] Ö ¾š& Jr þjò Ö ~. Ö jz 2~ JÒ ò. Ú [î² 1.3] Ö ò. ¾š& Jr þjò Chapter ~ JÒ ïê Ó úê Ó ïj:º Ó [î² 1.4] 2~ z& ¾š& Jr þjò Inventory Master File Maintenance Audit Listing új:º Ó Page1 Update Product Quantity Quantity Reorder Code Code On Hand On Order Point ACTION A DR Addition C DR Change -- Qty on hand A DR Addition A DR Addition D DR4000 Deletion C GR Change -- Qty on order C GR Change -- Reorder point A SA Addition C SA Change -- Qty on hand [î² 1.5] ê ª N š N þ Chapter 1-13 Chapter 1-7

8 Inventory Master File Maintenance Error Listing Page1 Update Product Quantity Quantity Reorder Code Code On Hand On Order Point ERROR MESSAGE D DR3000 Invalid Delete -- Master Not On File C GR Invalid Change -- Master Not On File A HM Invalid Add -- Master Already On File X HM1308 Invalid Update code Y SA3014 Invalid Update code A SA Invalid Add -- Master Already On File D SD1103 Invalid Delete -- Master Not On File [î² 1.6] ê ª N Æâ š þ Chapter 1-14 Inventory Master File Listing Page1 Product Quantity Quantity Reorder Code On Hand On Order Point DR DR DR DR DR GR GR GR GR HM HM SA SA SA SA [î² 1.7] ¾š& JrN š þ Chapter 1-15 Chapter 1-8

9 Inventory Master File Listing of Records With Page 1 Quantity On Hand BELOW Recorder Point Product Quantity Quantity Reorder Code On Hand On Order Point DR HM SA [î² 1.8] ¾š& Jr êæ ör Šs êön þ Chapter 1-16 Transactions Read 578 Adds 461 Processed 446 Invalid 15 Changes 87 Processed 79 Invalid 8 Invalid Update Codes 1 Master Records Read 28,406 Master Records Written 28,825 [î² 1.9] ª JrN þ Chapter 1-17 Chapter 1-9