DBMS Approach

Question 1

Database Management Approach Provides? (dm, dcl, cu, br, s, sqla, sGISsa) 7

Answer 1

1. A data model:
   ◦ Common and controlled approach for representing objects (points, lines, polygons)
   ◦ Controls how we add, modify, retrieve, and analyze data
   ◦ Data types
   ◦ includes: integer (whole numbers only), real (decimal), character (alphabetic and numeric characters), date
   ◦ may include pictures and images
   ◦ e.g. a database of buildings for the fire department which stores a picture as well as address, number of floors, etc.
   ◦ Data definition language (DDL)
   ◦ General term for tools used to determine the contents of the database
   ◦ e.g. SQL commands (Create, Create Table, Insert, Drop, Delete, Update, Alter, Rename, Truncate)
   ◦ e.g. XML Schema
2. Data conversion and loading
   ◦ Tools for converting and importing data with different file formats and coordinate systems.
3. Controlled updates
   ◦ Transaction manager controls multi-user access and updates to the database
   ◦ Versioning and reconciliation
   ◦ views database as a common resource
   ◦ program/data independence
   ◦ changes can be made to data without affecting other components of the system
   ◦ for example:
   ◦ change format of data items (real to integer, arithmetic operations)
   ◦ change file structure (reorganize data internally or change mode of access)
   ◦ relocate from one device to another, e.g. from optical to magnetic storage, from tape to disk
4. Backup and recovery
5. Security
   ◦ Controlled access (read and/or write) to the database for different users
   ◦ multiple applications, data sharing
   ◦ the user or programmer or application specialist need not know the details of how the data
   are physically stored on the system
6. Support for Query Languages and Analysis
   ◦ Support for standard query languages (SQL)
   ◦ Indexes to speed up searching
7. Support for GIS specific analysis
   ◦ Tools for the creation, using, and maintaining data
   ◦ Interfaces to support visualization and analysis

Question 2

What are the 5 Stages in GIS Development? PDPSS

Answer 2

1. Problem Recognition
   Project initiation may result from:
   ◦ technological advances (software or hardware)
   ◦ recognition that new information technology may:
   ◦ improve efficiency of current tasks
   ◦ help resolve new problems or allow new functions
   to be performed

Requires:
◦ user commitment
◦ understanding of user needs and information management problems to be addressed
◦ at least general awareness of technological capabilities

2. Developing Management Support
   Critical to the initiation and success of the project

May involve a feasibility study to determine Return on Investment (ROI):
◦ provide a documented starting point
◦ establish a communication network
◦ confirm expected costs/benefits
◦ manage user community expectations
◦ justify the system ( go or no go decision)
◦ provide basis for Request for Proposal (RFP)

Feasibility study focus on:
◦ Technical issues
◦ Cost/benefit issues
◦ Management and other issues

3. Project Definition
   Analysis of Requirements:
   ◦ Development of Objectives
   ◦ User Requirements Analysis
   ◦ identifying the current role of spatial
   information/analysis in the organization
   ◦ evaluating the potential for new/upgraded GIS
   based procedures
   ◦ Identify possible new workflows, products, services
   ◦ Preliminary Design
   ◦ Preliminary database specifications (size of data
   and types of information)
   ◦ Functional specifications (checking with potential
   vendors to determine functional capabilities of
   alternate systems)
   ◦ Survey the GIS market for potential systems
   ◦ Pilot Study
   ◦ Test a miniature version of the GI system.
   ◦ Secure buy-in from members of the organization
   ◦ Provide a test bed for application development
   ◦ Final Design
   ◦ Design specifications for inclusion in a Request For
   Proposals
   ◦ Database design
   ◦ Functional and performance specifications
   ◦ Requirements (mandatory, desirable, optional)
   ◦ Request For Proposal (RFP)
   ◦ RFP combines the final design document and
   contractual requirements
   ◦ Legal requirements
   ◦ Deliverables
   ◦ Services (training/support)
   ◦ Procurement and payment schedule

4. System Evaluation
Evaluation of Alternatives
◦ Scoring system developed for proposals
◦ Develop short list of vendors
◦ Score proposals and presentations
◦ Benchmarking
    ◦ A pilot version of each vendor’s system is 
    developed and evaluated
◦ Cost effectiveness analysis

Outcomes include:
◦ selection of hardware configuration
◦ selection of GIS software
◦ defines what spatial data types are supported
◦ defines role of DBMS and database model
◦ identification of custom development required to suit user needs

5. System Implementation
   Implementation Plan
   ◦ staging of system implementation and development
   ◦ role of in-house development vs sub-contracting
   ◦ allocation of financial and human resources

Negotiation of contract details
◦ Terms and conditions, costs, schedules

Acquisition and Installation

Acceptance Testing
◦ Test system to ensure that it meets specifications

Implementation
◦ Staff training
◦ Data collection
◦ Production use of the system
◦ Maintenance and ongoing performance monitoring

Question 3

Why database design?

Answer 3

Organization mandates
◦ Different organizations (or units within one organization) have different needs for data depending on their mandates and the activities
◦ Mandates often help identify and define entities of interest, based on a certain view of their world
◦ What might seem like the same data need in two different units can actually be quite different when we look at a more detailed level
◦ In a telecom company:
◦ Infrastructure represented differently in engineering and finance departments