Oracle 9i

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Oracle 9i

• Puneet Shadija
• Lecture - 1

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Agenda

• Understanding DBMS
• Database System Application
• Database Vs File system
• Database Models
• Hierarchical Model
• Network Model
• Relational Model
• Database System Structure

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What a Database is ???

• Collection of interrelated data a set of
  program to access those data.
• Goal is to provide way to store and retrieve data
  in an efficient and convenient manner.
• Word MANAGEMENT indicates - providing
  mechanism for
• Defining structure for storage of information.
• Providing mechanism for manipulation of stored
  data.
• Safety Mechanism

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Database System Application

• Banking
• Airlines
• Universities
• Credit card transactions
• Finance
• Manufacturing
• Human resources
• Sales

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Database Vs Filesystem

• Data redundancy inconsistency
• Difficulty in accessing data
• Data isolation
• Integrity problem
• Atomicity problems
• Concurrent-access anomalies
• Security problem

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Data Model

• Data model is a description of both a container
  for data and a methodology for storing and
  retrieving data from that container
• Few Data Models are
• Hierarchical Database model
• Network Database model
• Relational Database Model

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Hierarchical Model

• Hierarchical Database Model defines
  hierarchically-arranged data.

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Network Database Model

• Network Model

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Relational Database Model

• A relational database allows the definition of
  data structures, storage and retrieval operations
  and integrity constraints. In such a database the
  data and relations between them are organized in
  tables. A table is a collection of records and
  each record in a table contains the same fields.
• Features of RDBMS
• Values Are Atomic
• Each Row is Unique
• Column Values Are of the Same Kind
• The Sequence of Columns is Insignificant
• The Sequence of Rows is Insignificant
• Each Column Has a Unique Name

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Database System Structure

• Storage manager
• Authorization integrity manager
• Transaction manager
• File manager (space allocation)
• Buffer manager
• Query Processor
• DDL interpreter
• DML compiler
• Query evaluation Engine

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Database System Structure
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Questions ???