IBM started work on databases in the 1970s

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Introduction

• IBM started work on databases in the 1970s
• Honeywell first to create database programs
• Constantly updating
• Hierarchical, object oriented, network, and
  relational databases

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Hierarchical Databases

• First databases developed 1960s
• Hierarchical Structure
• Genealogy, parent-child
• One-one relationship
• One-many relationship

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http//www.wdvl.com/Authoring/DB/Intro/heirarchica
l_databases.html
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Problems with Hierarchical Structure

• No many-many relationship
• Difficult to find information unless you know the
  whole database

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Network Database

• Introduction
• -CODASYL Data Bas Task Group
• -DBTG model
• Why is it called network model?
• -refers to the way data is linked to other data.

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Data organization

• One-to-one relationship
• One-to-many relationship
• Many-to-many relationship

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Data

• Records
• -sets of related data values
• Record types
• -sets of records of same type
• Set types
• -relationships between two record types

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Relational Database

• Developed in the 1980s
• Most common form of database today
• Data is arranged in a table, called a relation,
  with rows and columns

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Sample relationcolumns attributesrows tuple
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Relational Database (cont.d)

• A group of related tables (relations)
• Each relation is labeled (title)
• Each also has a column or columns called the
  primary key, which uniquely identifies the row in
  the table

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Finding the Primary key
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Object-Oriented Database

• Different from others because it stores data AND
  INSTRUCTIONS together in the database
• The combination of data and intsructions is
  called an object
• Not in widespread use

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Object-Relational Database

• Combining object-oriented capabilities with
  relational databases

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Conclusion

• Important for businesses
• Each type of database serves its own purpose
• Fine tuning leads to bigger and better things