CA218 Introduction to Databases

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CA218 Introduction to Databases

• Lecturer Mark Melia

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Course Information

• Contact hours
• Lecture
• Wednesday 11.00-12.00
• Thursday 09.00-10.00
• Lab
• Thursday 13.00-15.00
• Phone [phone] (Ext. 8448)
• Email mmelia_at_computing.dcu.ie
• Web http//www.computing.dcu.ie/mmelia/ca218.sht
  ml

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Course Information

• Assessment
• SQL Test 12.5
• Week 8
• Project 12.5
• Given in week 9
• Submission week 11
• Final Exam 75

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So whats it all about???

• Information Systems (today)
• DB just a small cog in an information systems
  world
• Set the scene
• Database Overview (Week 1)
• DBMS
• What is it, why use it, why not to use it
• 3 level Architecture

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So what is it all about???

• Entity-Relationship Modelling (Week 2)
• A way of modelling the real world
• Well part of it anyway
• Database design analysis
• Relational Model of Data (Week 3)
• Mathematical foundation of relational databases

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So what is it all about???

• Structured Query Language (SQL) (Week 4-6)
• Creating databases (DDL)
• Manipulating and finding data in databases (DML)
• System Catalog (Week 6)
• How a DBMS describes its data
• Views (Week 6)
• Creating virtual tables

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So what is it all about???

• Databases and the Internet (week 7)
• Connecting java and databases
• Database design and normalisation (week 8 9)
• Storage Structures (week 10)
• Finished in week 10 yeah right!

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The Lab Sessions

• Play around with the ER modelling tool (Week 2)
  no tutors
• Worksheet 1 ER modelling (Week 3)
• Worksheet 2 Relational Algebra (Week 4)
• SQL Worksheet SQL questions (week 5, 6 7)
• Java and Databases (Week 8)
• Project (Week 9 11)

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So lets get stuck in!
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Information Systems

• This introductory lecture describes the role that
  a Database Management System (DBMS) plays in
  terms of other information systems.
• 1a. Information Systems Introduction
• 1b. Information Systems and DBMS
• Sources Elmasri Navathe pp 1-6

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Information Systems Introduction

• " A computer-based1 information system retrieves2
  information 3 from its database4 in response to a
  users query5 ".
• Manual v computer based
• Retrieve, store, modify, delete ... always 4 DML
  commands
• Computerised information could be ...
• structured numeric/alpha
• free text
• voice
• image
• rules
• others ...

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Information Systems Introduction

• " A computer-based 1 information system
  retrieves2 information3 from its database4 in
  response to a users query5 ".
• Database is a repository which is big and
  organised
• User query
• Precise or vague information need
• Expressed precisely or vaguely
• Interactive or batch execution / retrieval
• Seeking specific information or aggregate

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Information Systems DBMS

• So where does a DBMS fit in
• Interactive or host query
• Unambiguous statement
• Precise query
• Retrieved information is specifically stored or
  aggregated
• Well-structured information, text and multimedia
  are stored as bit strings
• Query is boolean combination of predicates
• Exact matching
• Formal schema
• DBMS also provides security, data independence,
  persistence, concurrency, recovery and backup