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Part 2 Remembering the Past With Organizational Memory - Database Copyright © 2001 by Harcourt, Inc. All rights reserved Organizational Memory Remember the Past (organizational memory) People and Technology Handling the Present (transaction processing system 2001 Decisions Preparing for the Future (decision support systems) Organizational Memory Data Information Numbers Text (tables & reports) Organizational Culture Characters Hypertext Social Networks Graphics (incl. charts) Problem Solving Models Images Audio 2001 Knowledge Video File Organization • Sequential • Direct (Random) • Indexed Sequential 2001 Database • Organized collection of related files – To relate, have common field – Shared across applications and functional areas – Reduced Duplications 2001 Data Hierarchy Database (collection of related files) File (table) Record (row) Field (column) Character (byte) Bit 2001 Database - Advantages • Data Redundancy - less duplication between applications causing inaccuracies • Data Dependence - data not linked to application • Data Integration -shared resource • Flexibility -access and view many ways • Better Security 2001 Data Storage Structured and Semistructured Organizational Memory Storage Type 2001 Data Information Knowledge Structured Database, data warehouse Indexed Web site, Groupware, reports, charts, expert systems, manuals FAQs, newsgroups Semistructured Unorganized list Web pages, e-mail Bulletin boards, chat groups DBMS Software Components • Data Definition Language • Data Manipulation Language • Data Dictionary 2001 Data Definition Language • Structure of Database – Schema • Field Name, Length • Type – Alphanumeric, Numeric, Date, Logic, Memo • Properties 2001 Data Manipulation Language • For use of database – Add / Change data – View data • Structured Query Language (SQL) • Report Generator – Organize records • Index or Sort – Delete records 2001 Data Dictionary • • • • • • Actual File Stores Definitions (Properties) Ownership Security Usage Data Element 2001 Views Logical • As it is viewed by an end user • The user is unaware of the fact that data is physically resident in two different files 2001 Physical • The actual organization of data within the computer storage device • The actual arrangement of data into entities, attributes, tables and databases Views • Logical – – – – – – – – 2001 Customer # Order # Product # Order Quantity Price Ship-to-Address Supplier Salesman # • Physical Entities Customer Order Product Tables for Special Orders at fareastfoods.com 2001 Customer Table Special Table Customer ID Last Name First Name E-Mail Address (other columns not shown) Product ID Product Name (other columns not shown) TYPES OR RELATIONS ONE-TO-ONE: STUDENT CLASS ONE-TO-MANY: STUDENT A MANY-TO-MANY: 2001 ID STUDENT B CLASS 1 STUDENT A STUDENT C CLASS 2 STUDENT B STUDENT C NETWORK DATA MODEL • Variation Of Hierarchical Model • Useful For Many-to-many Relationships CLASS 1 STUDENT A 2001 CLASS 2 STUDENT B STUDENT C RELATIONAL DATA MODEL • • • • Data In Table Format Entity: Table Tuple: Row (Record) In Table Field: Column (Attribute) In Table * 2001 2001 Relational DBMS Transaction processing systems Snapshot data *Extraction *Transformation *Cleaning *Loading 2001 Creating Warehouse * Decision Queries Data support warehouse Data systems *Data mining Using Data Warehouse Relational DBMS Relationships in Fareastfoods.com Database Customer Customer ID Last Name First Name E-mail Address 2001 Request Request Number Customer ID Product ID Special Order Products Product ID Product Name Fareastfoods.com Data Model 2001 Customer Request *Customer ID Last Name First Name E-mail Address *Request Number Customer ID Product ID Special Order Products *Product ID Product Name Structured query language (SQL) • SQL queries • Update • Delete • Add 2001 Sample SQL Query SELECT fields FROM tables WHERE fields match query condition SELECT LASTNAME, FIRSTNAME, EMAIL FROM CUSTOMER, REQUEST WHERE CUSTOMER.CUSTID = REQUEST.CUSTID ORDER BY LASTNAME; 2001 Properties of Relations • An entry at the intersection of each row and column is single-valued • Entries in columns are from the same domain and relate to the same attribute …name, address • Each row is unique and has a unique key. • The sequence of columns is insignificant. • The sequence of rows is insignificant. 2001 Relational Databases • Mainframe... – DB2 - IBM – Oracle (mini, micro) – SQL Server - MS • Microcomputer – – – – 2001 Access - MS FoxPro - MS Paradox - Borland dBASE IV - Borland Normalization • The process of creating small data structures (tables) or entities from complex groups of fields (attributes). – minimize redundancy – easily allows insertion, deletion, and modification without inconsistencies. 2001 Normalization Guidelines • Remove all repeating attributes (1NF) – one to many relations • All non-key attributes are dependent on full-key attribute(s) and not just part of it. (2NF) – compound key entities • Non-key attributes not dependent on any other non-key attribute. (3NF) 2001 Designing NEW Database • • • • Determine Attributes (fields) Determine Entities (tables) Normalize Entities Determine Keys – Unique Key (_____) – Foreign Key (_ _ _ _) • Show Relationships (Lines between keys) 2001 Object-Oriented Databases • Data and Procedures Stored Together; can be Retrieved, Shared • Data/Procedures is Object – – – – – Document Graphic Video Text Sound • Used in Multimedia 2001 DATABASE TRENDS • HYPERMEDIA: – Text, Graphics, Sound, Video, Programs. – Nodes Connected by Links • HYBRID - Object and Relational – Can store Graphics, Video, Sound… * 2001 Distributed Databases • A database which is accessed and maintained at multiple locations. • To avoid failure: – Replicated - central database is duplicated at remote location(s). – Partitioned - database is subdivided and only portion used is available at remote sites. All at central. 2001 Security • Who has access to data? – Read, Write, Change, Delete • Length of Retention – 1 month, Until paid, Historical • Back-up – On-site, Off-site, How often • Audit Trail – Record of update, who, when, log 2001 Data Warehouse - Advantages • Enterprise-wide view of business • Executive and Management planning and decision making • Access, not change! 2001 DATABASE ADMINISTRATION • Defines & Organizes Database Structure And Content • Develops Security Procedures • Develops Database Documentation • Maintains DBMS 2001 Information Management • Electronic imaging –Scanner –Portable document format (PDF) 2001 Problems with Paper Storage of Information Problem 2001 Explanation Storage costs Paper documents are expensive to store in filing cabinets and storage cabinets Time costs A large amount of time can be required to find documents Multiple access (sharing) Paper documents (or microfiche/microfilm) must be copied to be available to multiple people Transmission delay Paper documents can take a long time to be sent from one place to another Information manipulation Information on paper (or microfilm/microfiche) must be manually extracted; also, it is not easily searchable Backups Backups of paper documents are seldom kept due to space problems Knowledge Management • Groupware • Group support systems • Videoconferencing • Document-based groupware 2001 • Expert systems –Knowledge base –Inference engine –Domain database –Rule database –If-then rule –Logic trace 2001 Elements of Expert Systems Knowledge Facts Knowledge Base Inference Engine User 2001 Preparing for the Future with Decision Support NEXT SLIDE PAST SLIDE 5 - 41 Copyright © 2001 by Harcourt, Inc. All rights reserved Database Case Exercise • Determine Attributes (given) • Determine Entities (tables) • Determine Keys – Unique Key (_____) – Foreign Key (_ _ _ _) • Normalize Entities (3 rules) • Show Relationships (Lines between keys) – One to Many 2001