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Data Management

Data Management. Chris Wallace 3P14 chris.wallace@uwe.ac.uk Book Various Database texts Last year Database Systems Paul Beynon-Davies £24.99 Exam 50% CourseWork 50% Web Site: www.cems.uwe.ac.uk/~cjwallac/UFIE8K. Lecture 1. Workplan SQL Workbook Basic Terminology -

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Data Management

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  1. Data Management • Chris Wallace • 3P14 • chris.wallace@uwe.ac.uk • Book • Various Database texts • Last year Database Systems Paul Beynon-Davies £24.99 • Exam 50% CourseWork 50% • Web Site: www.cems.uwe.ac.uk/~cjwallac/UFIE8K

  2. Lecture 1 • Workplan • SQL Workbook • Basic Terminology - • Universe of Discourse, Data Schema, FactBase, Integrity, Database functions, Data model, Data/Information/Knowledge

  3. Workplan

  4. Learning SQL workbook • Based on a simple model of employees and departments in a company • Workbook takes you through the basics • Workbook covers three different DBMSs • Access • Oracle • MySQL • You can use any of the DBMSs but MySQL is preferable

  5. Universe of Discourse - UoD Part of Real world of interest Physical,Living,Active e.g. the real life ‘Mr Smith’ Database Representaton of UoD Abstract, Symbolic, Passive e.g. the record with employee no 7369 UoD <> Database

  6. Database Schema A theory of the UoD General e.g. Emp table definition Develops during design ‘Static’ during use Intension Factbase Facts about the UoD expressed in Schema Specific to time, place E.g. employee with empno=7499 has name ‘ALLEN’ Changes during use - Sequence of States Extension Schema <> Factbase

  7. Consistancy Factbase agrees with Schema Internal to DBMS Defined in Schema - ‘integrity constraints’ Checked by DBMS Exact Failure causes crash Veracity Factbase agrees with UoD Between DBMS and UoD Checked by humans ‘good enough’ - issue of Data Quality Failure causes errors Integrity ??

  8. Query Extracts existing facts and derives new facts Leaves Factbase unchanged SELECT … Update Reflects some change in the UoD Changes state of factbase Must check integrity constraints UPDATE .., INSERT.., DELETE.. Types of Database Function

  9. Data Schema e.g. Table definitions for Member, Facility, Booking Extension of a ‘Meta-model’ Architectural Data Model e.g. Relational Access 97, 2002 Oracle 7, 9i or Object-oriented Tables for Table, Field, Relationship, Query ‘Meta-model’ Data Model??

  10. Data <> Information <> Knowledge • Data - basic facts • employee with no=7369 has sal=800 • Information - deduced facts • The President has 3 staff reporting • The organisation has 4 levels of hierarchy • Knowledge - information in context • Staff turnover is low for the size of company and industry sector

  11. Tutorial • You will need a login on the Windows 2000 system • Open a browser and locate the model home page • Locate the SQL workbook. It is easier to copy and paste code from the book but you have a hard-copy to keep notes in as well.

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