1. GIS & Databases
Ming-Chun Lee

2. Data vs. Information Data: raw fact
Information: data processed to reveal meaning
Database system transforms data into information through queries

3. Data vs. Database Database is a collection of related data
Database stores data in an organized manner
Database exists, first and the foremost, to serve users’ requirements

4. Data Modeling
From GIS perspective, database is the “physical” form of data representation
Describe the reality in terms of different concepts to either physical objects, such as a house, a parcel, or social/political meanings, such as land uses, zoning codes, postal zip codes.
In the GIS representation, GIS needs to know the logic behind all the visual graphical elements on either a computer display or a map. A polygon representing a house has to be fully within another polygon representing a parcel.

5. Data Modeling Conceptual Model - How humans see the world
Users’ view of the world (interpreted by data)
Logical Model - How programs see the world
Precise definition of the set of objects of interest to identify the relationships between them including such relationships as “located at”, “owned by”, “is part of”
Physical Model - How machines see the world
Implementation of data model within the framework of relational database technology

6. Object Relationships
One-to-One
One-to-Many
Many-to-One
Many-to-Many

7. Types of Databases Flat File Hierarchical Relational
Single Table; No Relationships
Hierarchical
Nested Tables
One-to-One & One-to-Many Relationships
Relational
Interrelated Tables
One-to-One, One-to-Many, Many-to-One, Many-to-Many Relationships

8. Flat File Database ID Route Timepoint 1 Timepoint 2 … Timepoint 10 171
4th Ave. S & S Washington St.
5th Ave. S & S Jackson St.
50th Ave. NE & NE 75th St. 2 72
Ravenna Ave. NE & NE 80th St. 3 73
15th Ave. NE & NE 125th St.

9. Hierarchical Database
TPID
Timepoint 1
4th Ave. S & S Washington St. 2
5th Ave. S & S Jackson St. … 10
50th Ave. NE & NE 75th St. ID
Route 1 71 2 72 3 73
TPID
Timepoint 1
4th Ave. S & S Washington St. 2
5th Ave. S & S Jackson St. … 10
50th Ave. NE & NE 75th St.
TPID
Timepoint 1
4th Ave. S & S Washington St. 2
5th Ave. S & S Jackson St. … 10
15th Ave. NE & NE 125th St.

10. Relational Database ID Route 1 71 2 72 3 73 OID Route TP Order 101 71
102 2
110 10
201 72
202
210
301 73
302
310
TPID
Timepoint 1
4th Ave. S & S Washington St. 2
5th Ave. S & S Jackson St. …
110
50th Ave. NE & NE 75th St.
210
Ravenna Ave. NE & NE 80th St.
310
15th Ave. NE & NE 125th St.

11. Relational Database Concepts
One Table for Each Type of “Thing/Entity”
Within a Table: One Row for Each Distinct “Thing” of that Type
Primary Key: A Unique Identifier for the distinct “Thing”
Foreign Key: A Reference to Another Table’s Primary Key

12. GIS as a Relational Database
Join Tables to Spatial Data Layers
User ID
Name
Abbrev. 10
Washington WA 12
Oregon OR 18
Michigan MI ID
Area
Perimeter
User ID 1
25.3
10.4 10 2
30.2
13.5 12 3
10.1
8.2 18 4
27.8
12.6

13. Object-oriented Database
The idea of "object-oriented" database is to organize information into the sorts of “objects" that people recognize.
Instead of "decomposing" each feature in a distinctive list of attributes, features are stored as collections of attributes and behaviors.
A class is a computer construct representing a concept bound in a cohesive package
Some are concrete (i.e. real world)
Bank account
Rental item
Database item
Pile
Others are abstract
Scanner
Stream
Math
An Object: An instance of a CLASS
Contains meaningful data
Concepts that occupy memory space at runtime are, according to the definition, objects

14. Object-oriented Databases
Feature
Object
Relationship

15. Object-oriented Database
It enables you to make the features in GIS datasets smarter by endowing them with natural behaviors and relationship among features.
It brings a physical model closer to its logical model. The users work with objects of interests such as roads, lakes and transformers.

16. Features, Objects, and Relationships

17. Object-oriented Relational Databases
ArcGIS uses a geographic data model that represents spatial information as objects, features, raster, and other data types.
It integrates two GIS data models, the traditional relational database model and an object-oriented relational model called a geodatabase
All persistent (database) information is still in tables, but some of the tabular entries can have richer data structure

18. Object-oriented Relational Databases
All database information is still in tables, but some of the tabular entries can have richer data structure

19. GIS architecture Built upon relational database
Spatial/non-spatial data are stored in tables
Storing spatial data in table is tedious
Built upon object-oriented database
Can define user-defined data type (e.g. ArcGIS geodatabase has different data models such as hydrology, network, land parcel, and so on)