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Data at the Core of the Enterprise. Objectives. Define of database systems Introduce data modeling and SQL Discuss emerging requirements of database systems. DATA. ?. INFORMATION. Attributes of data. Sharable Moveable Secure Accurate Timely Relevant. Data hierarchy. Bits

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objectives
Objectives
  • Define of database systems
  • Introduce data modeling and SQL
  • Discuss emerging requirements of database systems
slide3

DATA

?

INFORMATION

attributes of data
Attributes of data
  • Sharable
  • Moveable
  • Secure
  • Accurate
  • Timely
  • Relevant
data hierarchy
Data hierarchy
  • Bits
  • Characters
  • Fields (columns)
  • Records (rows)
  • Files (table)
  • Database
why build a database
Why build a database?
  • Handle large amounts of data
  • Satisfy multiple users
  • Make information retrieval faster
  • Make data input faster
  • Provide greater accuracy
database versus database management system dbms
Database versus Database Management System (DBMS)
  • Database is a self-describing collection of integrated files
  • A DBMS is a complex computer program that acts as a data librarian, supervising the transfer of data between the end user and the database
advantages of dbms
Advantages of DBMS
  • More info from the same data
  • Reduction of data duplication
  • Improved data integrity
  • Programs are independent of the data format
  • Sharing of data resources
and disadvantages
…and disadvantages
  • Added expense
  • More hardware may be needed
  • If it crashes….
  • Sophisticated design and programming required
  • Additional training
  • Security is critical
relational model
Relational model
  • Relation? Attribute? Tuple?
  • Keys
    • Primary and foreign
  • Referential integrity
  • Relational algebra
relational db rules
Relational DB rules
  • Every row must have exactly the same number of columns (fields or attributes)
  • Each row can have only one value stored in each column (fields or attributes)
  • A column must contain the same kind of value in every row of that column
  • No two rows can be exactly the same
  • The order of the rows or of the columns can’t be used to provide information
terminology
Terminology

Data

Processing

Informal

Relational DB

Formal

Relational DB

File

Table

Relation

Record

Row

Tuple

Field

Column

Attribute

data modeling
Data modeling
  • Purpose: control and visualization
  • Process: gathering requirements
  • Results: forms and diagrams
normalization
Normalization
  • Purpose:
    • Avoid anomalies
    • Reduce redundancy
  • Process:
    • Successive application of rules
    • Bottom-up (data drives process)
    • Move from first through fifth normal form
    • Does it make more or less tables?
entity relationship modeling
Entity relationship modeling
  • List the entities or objects in the environment
    • People, things, transactions
  • Describe the relationship between them
    • A single row in table A can be related to how many rows in table B (one or many)
    • A single row in table B can be related to how many rows in table A (one or many)
erd questions
ERD questions
  • What are the subjects/objects of the business?

data entities

  • What unique characteristic(s) distinguishes each object from others of same type?

primary key

  • What characteristics describe each object?

attributes

  • How do you use this data?

controls & meaning

erd questions1
ERD questions
  • Over what period of time are you interested in this data? cardinality & time dimensions
  • Are all instances of each object the same?

supertypes, subtypes, aggregations

  • What events occur that imply associations between objects? relationships (cardinality & degree)
  • Is each activity or event always handled the same way or are there special circumstances?

integrity rules, cardinality, time

slide21
SQL
  • Definition (DDL)
    • CREATE, ALTER, DROP
  • Manipulation (DML)
    • SELECT, INSERT, UPDATE, DELETE
  • What’s the most used sql command?
general format of select
General format of SELECT

SELECT [DISTINCT] item(s)

FROM table(s)

[WHERE condition]

[GROUP BY columns]

[HAVING condition]

[ORDER BY row(s)]

emerging data requirements
Emerging data requirements

Complex

Graphics

Video

Audio

HTML/

SGML

Video Streams

Spatial Data

Time Series

Unstructured

Structured

Images

Text

Current RDBMS

Audio Streams

Simple

summary
Summary
  • Defined of database systems
  • Introduced data modeling and SQL
  • Discussed emerging requirements of database systems