Data Creation and Maintenance: Use of Database Management system

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Data Creation and Maintenance Use of Database
Management system
PADM435
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Three Classic Data Models

• Database (Information to be stored)
• Geographic database is heart and soul of GIS
• There are 3 types
• Relational Simple records stored in a 2D table
  in which every filed can be used as a key.
• Object Object oriented special query, not
  commercially successful
• Object relational Hybrid

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Database Management Systems

• DBMS is a software application to organize
  effective and efficient storage and access of data

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Database Management Systems Capabilities

• Data model (both geographic and non-geographic,
  info). May be integer or floating point
• Data load Provide tools to load data
• Index Helps searching
• Standard Query Language DBMS support query
  language

• Security controlled
• Updating Controlled
• Backup and recovery
• DBMS administration tools
• Applications Reports
• Programmable

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Relational database file organization

• Records Horizontal row 0f XLS sheet
• Fields Column names, that contains data items
• Keys one or more fields used for data retrieval

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Advantages of a DBMS

• Centralized control
• Efficient sharing
• Data independence
• Easier applications for new data
• Direct user access
• Control of redundancy
• Can create multiple user views

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Disadvantages of a DBMS

• Added cost
• Added complexity
• Centralized risks

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Why Relational Data model common in GIS

• Common in GIS
• 1. There is no hierarchy
• 2. Every data filed can be used as a key
• 3. Records are kept in 2-D Tables
• 4. Can use any filed for searching singly or
  together
• 5. You can join or relate data
• 6. Redundant data storage can be reduced
• 7. No restriction on queries, so GIS uses them

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Main Advantages

• More flexible than other models
• Has sound theoretical base. Can apply math. But
  interface is a programming language
• Organization easy to understand and communicate
• Less redundancy

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Main Disadvantages

• Difficult to implement
• Slower performance/ added complexity
• But need programming language support
• Cost
• Centralized risk

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Query Languages

• Query language is part of any DBMS
• In complex databases (Query types supported for
  Hierarchical and Network) query are defined while
  they are constructed
• In relational DB, query language is independent
  of the structure. Non-procedural language or
  Standard query language ( E. g. SQL by IMB)
• Has sound theoretical base. Can apply math.

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Geographic database design

• International standard institute
• Open GIS consortium standard
• There are 9 methods of testing spatial
  relationships ( Equal geometry, disjoint,
  intersect, touches, crosses, within, contains,
  overlaps, relate)