database design concepts be

8/6/2019 Database Design Concepts BE

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3/10/2005 1

Database Design Concepts and

Data Integration

URISAFebruary 9th, 2005

Bob Earle


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Agenda

A few Design tips and guidelines, some ofwhich I learned thehardway

Many GIS staff get database design and

maintenancethrust upon them

The revolution of GIS at Sacramento

County; how we became adata integrator,but not necessarily by plan


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Design of a Spatial system is like any other Enterprise application


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Earlier is Better


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Translation of User Requirements

Business RulesModel the Users View


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Entity Relationship Diagram

Good design tool, good communication tool


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Access ERD (Relationships)

You may already have an ERD tool and not know it


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Sacramento County ERD


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Normalization

Remove RepeatingGroups

Every non-key column

must be dependent onall parts of the primary

key

No non-key column

may be functionallydependent on anothernon-key column

Introduced by E.F. Codd


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Every attribute will refer to the

Primary key, the whole key and

nothing but the key, so help meCodd

A table should have a field that uniquely identifies

each of its records, and each field in the table should

describe the subject that the table represents

Database Design for Mere Mortals by Michael Hernandez


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Database Data Models


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Metadata


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Database Design Fallacies Design your system to replicate existing practices

You can throw your data model away when you

have implemented your database

I will just put it in a note Metadata is too much trouble

My spreadsheet is good enough

GIS shouldnt be putting its nose into everybodys

business


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More Database Design Fallacies Nobody will ever need my data

Just import your shapefiles into SDE and

voila you have a Geodatabase

Normalized data is fast performing data

Spatial data is just data


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Database Design Truths

Spatial data is just data Design on paper, then a computer

Earlier is better Document deviances from the conceptual

design


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More Database Design Truths

Use meaningful attribute and table names Flag for deletion, rather than delete

Take the users key away Use database constraints, rather than coded

business rules


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What is so Special about Spatial

Data? How it is the same than regular data

Data relationships Integrity

Key Asset

How it is different Spatial Key (Location is a type of key)

Topology

Heavy load Long transaction

Advanced data type

Database


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Early GIS


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Community GIS


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Evolution of the spatial data modelIan McCarg

Design With Nature

ArcInfo

Coverages

Oracle Spatial

True SpatiallyEnabled

Database

True SpatiallyEnabled

Database

GeoDatabaseShape File

ArcStorm

SDE


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GIS Layers

Points

Lines

PolygonsSurfaces


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3 D


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Scanned Maps


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Scanned Documents


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Attribute Data


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Orthophotography


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Levels of Data Integration


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If it were a perfect (GIS) World

SpatialInt

ernet

Universal

DatabaseTransactions Regional

DepartmentalDocume

nts


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I cant say it was

easy, but I can say itwas worth it!!

Sacramento County PropertySystems


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Systems(Without data sharing)

GHB/GAXApplications(Mainframe)

CPSUnsecured Tax

Application(Oracle)

GIS(ESRI)

APSPermits system

(Oracle)

PDBApplication(Mainframe)

SAP/COMPASS

(Oracle)

Utility Billing/CUBS

(SAP?,Oracle?)

Planning

Public WorksDirect Levy

Maintenance

Application

Sacramento County Property


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County-wideShared

PropertyData Warehouse

GHB/GAXApplications(Mainframe)

CPSUnsecured Tax

Application(Oracle)

GIS

(ESRI)

APSPermits system

(Oracle)

PDBApplication(Mainframe)

SAP/COMPASS

(Oracle)

Utility Billing/CUBS

(SAP?,Oracle?)

Planning

y p ySystems

Public WorksDirect Levy

MaintenanceApplication


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Examples of

Shared Data Benefits

Tax Rate Areas Vineyards

Utility Billing Minimize data redundancy and costs in the

Regional Cooperative


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Data Ownership, Dissemination, and

Accessibility Policies

Ownership - Departments own their data,

GIS is the middleman

Dissemination - Open Access, Cooperative

Mapping based on Standards

Access - Concerns over safety


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Database Architecture

Warehouse

Shared

Trans-actional

Warehouse

Shared

Trans-

actional

Firewall

fi f


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Summary - Benefits of

Good Design Data integrity

Flexibility in data retrieval and analysis

Follows business rules and therefore supports

organizational requirements Easier to share data

Different users access same data

Accommodates different views of the data

Minimal Data Redundancy

Breaks out of Spreadsheet mentality


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Questions, Comments?

[email protected]

[email protected]@saccounty.net
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