what is distributed database management system ppt

... system status, describes how to obtain the Lore system, and discusses current and future work 2 Representing and Querying Semistructured Data To set the stage for our discussion of the Lore system, ... a rich mechanism for structure discovery Such features, described in [AQM+96], are beyond the scope of this paper 3 System Architecture The basic architecture of the Lore system is depicted in ... into the database In object that cannot be accessed by a path from some name is considered to be deleted In an OEM database, there is no notion of xed schema All the schematic information is included

Ngày tải lên: 23/03/2014, 12:20

... compromise of the DBMS occurs as a result of a database user (intentionally or otherwise) performing actions the individual is authorised to perform 35 This threat is included because, whatever ... countered by the DBMS.T.ACCESS Unauthorised Access to the Database An outsider or system user who is not (currently) an authorised database user accesses the DBMS This threat includes: Impersonation ... after system failure or other discontinuity, recovery without protection (i.e security) compromise is obtained O.QUOTA Administrators of the database must ensure that each user of the TOE is configured

Ngày tải lên: 07/03/2014, 23:20

... consulting …etc) If this user is the system administrator then gusts can only do search inside this database and they are not authorized to generate and/or store data This new DBMS supported ... freely distributed Users can download these programs after his online registration these sets of programs were created based on: a) Some open source atomic codes [6] that are freely distributed ... difference between the current used atomic databases and AIMS is based on our objectives and they are: a) The building of AIMS [9], the online Database Management System (DBMS) to facilitate the process

Ngày tải lên: 23/03/2014, 12:20

... This review was conducted pursuant to a request by the Legislature and questions raised at a legislative hearing on October 28, 2009 This review focuses primarily on the Court Case Management System ... and interviews with project staff 3 What are the significant risks/issues the project is experiencing and what are the recommendations to address them? This is performed by document review, staff ... artifacts/plans exist? This is performed by a review of the project documentation 2 Is there evidence/validation that the plans are adequate and used operationally and effectively? This is performed

Ngày tải lên: 30/03/2014, 01:20

... Management System Lesson 1 / Slide 1 of 12©NIIT Introduction to Relational Database Management System Objectives In this section, you will learn to: • Define a Database Management System (DBMS) ... External Level This is the highest level, one that is closest to the user It is also called the user view. The user view is different from the way data is stored in the database This view describes ... instructor is concerned with only a portion of database that is relevant to the instructor and the administrator is concerned with only the portion of database that is relevant to the administrator

Ngày tải lên: 01/08/2014, 09:22

... 3MỤC TIÊU  Trình bày cái nhìn bao quát về cơ sở dữ liệu (Database) cũng như về hệ quản trị cơ sở dữ liệu (DBMS), hệ Cơ sở dữ liệu (Database System).  Các yêu cầu khi xây dựng một DBMS.  Một số ... 453453453 07/31/1972 333445555 5 Chương 1 : Nhập môn Hệ Quản Trị CSDL Trang 11DBMS (Database Management System)  Một phần mềm hệ thống cho phép định nghĩa, xây dựng xử lý và bảo trì dữ liệu ... hoạt động Tên, địa chỉ, số điện thoại của khách hàng  Báo cáo doanh thu Trang 9Database (tt)  Cơ sở dữ liệu (Database)  Một tập hợp có cấu trúc của những dữ liệu có liên quan với nhau được

Ngày tải lên: 17/10/2014, 07:23

... designed to store and manage database  DBMS is helpful in maintaining and utilizing a database Trang 8Database Management System Capabilities of database management system Trang 9Data dictionary ... airline ticket  Register a new course in university  Buy book in the bookstore  Library management  … Trang 6Database Simplified database view Trang 7Database Management System  DBMS ◦ A general ... interfaces Trang 24Summary  The main objective of database management system is to store and manipulate the data in an efficient manner  A database is an organized collection of related data  All

Ngày tải lên: 15/05/2017, 11:13

... 1Distributed database  Management Systems Lecture 03 Trang 2Resembling SetupsTrang 3Distributed Files: A collection of files  stored on different computers of a  network; not a DDBS DDBS is logically related, common  ... Computer System CPU Memory Computer System Shared Secondary Memory Shared Everything Loose Coupling Trang 6CPU Memory Computer System CPU Memory Computer System CPU Memory Computer System Switch ... Nothing Trang 7DDBS is also different from a  centralized system having C/S  system involving network Trang 8Reasons for DDBSTrang 9Consolidate data for integrated  decisions Reduce telecommunication costs

Ngày tải lên: 05/07/2022, 13:30

... Trang 1Distributed Database  Management System  Lecture 04 Trang 2Fragmentation  Transparency Trang 3 Transparency is desirable but there  is a compromise between level of  Transparency and difficulty/cost ... OS Support Heterogeneity   Relationship among  them  Trang 13Directory Management Distributed DB Design Concurrency Control Deadlock Management Reliability Query Processing Trang 14Thanks ... T R/F T Layers of Transparency Trang 6 Reliability through Distributed Transactions: Avoids simple point of failure  Concurrency Issues: Transaction involving  multiple records  Failure Recovery: Involving multiple sites

Ngày tải lên: 05/07/2022, 13:30

... Trang 1Distributed Database Management System Lecture 05 Trang 2 Virtual University of Pakistan 2Data Model • A set of tools/ constructs used to model a database • Record/Semantic ... Virtual University of Pakistan 21there is a unique value in Y, then X functionally determines Y, X  Y Trang 22 Virtual University of Pakistan 22• If X Y and there is a Z X and ZY, then X ... University of Pakistan 24there is unique value of (Y,Z) pair and Z depends only on X then X multidetermines Z, X Z Trang 25 Virtual University of Pakistan 25Trang 26 Virtual University of Pakistan 26•

Ngày tải lên: 05/07/2022, 13:31

... Trang 1Distributed Database Management Systems Lecture # 8 Trang 2In the previous lecture• Integrity Rules • Data Manipulation Languages Trang 3In this Lecture• Derived Relational ... Coupled–Programming Language and database languages are merged • Loosely Coupled –PL is extended with special concepts Trang 17Computer NetworksTrang 18A computer network is a system for communication ... F S = A(RA S) B Trang 5• The division of R with degree r with S with degree s is the set of (r-s)-tuples t such that for all s-tuples u in , the tuple tu is in R. R S = A(R)- A( A(R) xS)-R)

Ngày tải lên: 05/07/2022, 13:32

... subnet Trang 20Distributed DBMS Architecture Trang 21 Architecture of a systems defines its structure Trang 22 Sheth, A P., Larson, J A., ‘ Federated Database Systems for Managing Distributed Heterogeneous, ... Trang 1Distributed Database Management Systems Lecture 09 Trang 2In the previous lectureAlgebra Ops… Trang 3In this LectureTrang 4ScaleTrang 5• Local Area Network• ... Autonomous Databases’, ACM Computing Surveys, 22, No 3, p(183-236), Sep., 90 Trang 23• Three major (idealized) architectures of DDBMS discussed –Peer to peer –Client/Server –Multidatabase Trang

Ngày tải lên: 05/07/2022, 13:32

... Trang 1Distributed Database Management System Lecture 10 Trang 2 Virtual University of Pakistan 2• The functions in ANSI/SPARC Architecture • Square ... of Pakistan 5Architectural Alternatives SemiAutonomout, Total Isolation) Peer to Peer) Heterogeneous) Trang 6 Virtual University of Pakistan 6Trang 7 Virtual University of Pakistan 7No distribution, ... Architecture • Autonomy • Distribution • Heterogeneity Trang 4 Virtual University of Pakistan 4 Heterogeneity: Different component databases has a common thing that is represented by different

Ngày tải lên: 05/07/2022, 13:32

... Trang 1Distributed Database Management System Lecture 10 Trang 2Major DDBS ArchitecturesTrang 3Client-Server Architecture• Basic idea is to distribute functionality • Gives ... them • One Server Multiple Clients • Multiple Servers time Trang 6Peer-to-Peer Distributed SystemsTrang 7LIS1 LIS2 LISnGCS ES1 Trang 8• Physical data organization at each site defining Local Internal ... Physically accesses the data as  per the commands generated  Trang 12A Multidatabase Systemautonomous heterogeneous, and distributed databases Two Major architectures: • Global Schema Architecture • Federated

Ngày tải lên: 05/07/2022, 13:33

... Trang 1Distributed Database Management Systems Trang 2 L External Schema  G External Schema Global Schema Component Schema ... our Architecture discussion • Lets summarize Trang 9• Schema Design The DDB Design concerns two major steps, Schema Design and Schema Distribution • Schema Distribution Distribution of Schema ... Trang 11System Requirements (Objectives) Conceptual Design Distributed Design View Design Local Conceptual Schemas User Input View Integration User Input Trang 12• Conceptual Design is Global

Ngày tải lên: 05/07/2022, 13:33

... Trang 1Distributed Database Management Systems Lecture 13 Trang 2 Virtual University of Pakistan 2How Interests of the local and head offices mar result following vertical partitions of this table: ... of Pakistan 10• Disjoint ness: if data item x is in Rj, it is not in any other fragment ∀ ∀ x Rx R∈∈ i, R R∃∃ j such that x R such that x R∈∈ j, i ≠ j Trang 11 Virtual University of Pakistan ... of Pakistan 63- Degree of Fragmentation Between no to the extreme level that could be to the individual tuple or column level; a compromised decision Trang 7 Virtual University of Pakistan

Ngày tải lên: 05/07/2022, 13:33

... Trang 1Distributed Database Management Systems Lecture 14 Trang 2 Minterm predicates: given a set of simple predicates Pr = {pr1, pr2, …, pm}for a relation R, the set of minterm predicates M is ... University of Pakistan 9• A PHF is defined by a selection operation on the owner relations of the database schema, given a relation R, its PHF are given by Ri = Fi (R), 1 ≤ i ≤ w – Where F j is a selection ... sal ≤ 30000  (PAY)Trang 13 Virtual University of Pakistan 13Trang 14• Defining simple predicates may be tricky Trang 15 Virtual University of Pakistan 15 A set of simple predicates Pr is said to tuples of the minterm

Ngày tải lên: 05/07/2022, 13:34

... Trang 1Distributed Database Management Systems Lecture 15 Trang 2 Virtual University of Pakistan 2PHF- Minimality of Pr Trang 3 Virtual University of Pakistan 3• A relevant predicate is the one ... Pakistan 21Trang 22 Virtual University of Pakistan 22• Implications must be based on the database semantics not on a particular extension of the database Trang 23 Virtual University of Pakistan ... of Pakistan 13predicates M according to which relation R is to be fragmented Trang 14 Virtual University of Pakistan 14• Pr‘ ← COM_MIN (R,Pr) predicates Trang 15 Virtual University of Pakistan

Ngày tải lên: 05/07/2022, 13:34

... Trang 1Distributed Database Management Systems Lecture 14 Trang 2– The set of partitions for owner – Member relation – ... Pakistan 5DHF 1-Derived fragmentation may follow a chain, like PAY-EMP-ASIGN 2-Typically, more than one fragmentation options are there, which one adopted is an allocation problem discussed ... cases Disjointness: Simple in PHF if the pi in Pr’ are mutually exclusive; in DHF, guaranteed in case of simple join graph, however in case of partitioned join graph it is hard to establish Trang

Ngày tải lên: 05/07/2022, 13:36

... Trang 1Distributed Database Management Systems Trang 2In this Lecture• Continue with VF – Attribute affinities Trang 3 Replication of Key attributes does not violate the disjoint ness ... matrix CA Trang 21Global Affinity Measure (AM)Trang 22• Affinity Measure is a single value that is calculated on the basis of positions of elements in AA and their surrounding elements Trang ... 4Vertical Fragmentation Information RequirementsTrang 5• Basic idea of VF is access efficiency • Information Requirement is application based • Attribute affinities: obtained from more primitive

Ngày tải lên: 05/07/2022, 13:36