Introduction to Spatial Databases and DBMS

Introduction to Spatial Databases

• Spatial databases store information about spatial location, relationships of geographical features, and attributes.

Fundamental Database Concepts

• Database Management Systems (DBMS) are the foundational framework for information systems, significantly changing organizational operations.
• DBMS remains an active research area with ongoing problems.

File-Based System

• The predecessor to the DBMS was the file-based system.
• This system consists of application programs designed for end-users, typically for report generation.
• Each program manages its own data, leading to data redundancy and program dependence.

Database Approach

• The database approach emerged to solve problems of file-based systems.
• A database is a logically related collection of data with descriptions to meet organizational information needs.
• A DBMS is software that allows users to define, create, maintain, and control database access.

Application Programs

• An application program is a computer program that interacts with the database, typically through SQL statements submitted to the DBMS.
• The database system manages a collection of application programs that interact with the database and the DBMS itself.

DBMS Provides

• A Data Definition Language (DDL) to define databases.
• A Data Manipulation Language (DML) to insert, update, delete, and retrieve data.
• Controlled access to the database, including security, integrity, concurrency, recovery control, and user-accessible catalog.
• View mechanisms simplify data for users.

DBMS Components

• Hardware (computer)
• Software (DBMS, operating system, and application programs)
• Data
• Procedures
• People (data/database administrators, database designers, application developers, and end-users)

DBMS vs. Flat File

• DBMS: Multi-user access, designed for small/large businesses, removes redundancy and integrity issues, expensive but cost-effective in the long run, facilitates complicated transactions.
• Flat File: Does not support multi-user access, limited to smaller system, has redundancy and integrity issues, cheaper, doesn't support complicated transactions.

Advantages & Disadvantages of the Database Approach

• Advantages: Control of data redundancy, data consistency, data sharing, improved security/integrity
• Disadvantages: Complexity, cost, reduced performance, impact of failure

DBMS Advantages

• Efficient data storage and retrieval
• Balances needs of multiple applications
• Provides uniform administration procedures
• Application programmers not exposed to data details
• Offers data integrity and security
• Protects against unauthorized access
• Supports concurrent user access
• Reduces application development time

DBMS Disadvantages

• High hardware/software costs
• Often complex systems
• Training required for usage
• Potential damage due to data integration within a single database (e.g., electric failure)
• Data loss due to concurrent use
• Limits in performing complex calculations

Spatial Database

• Includes information about spatial location, relationships between geographic features, and attributes.

Spatial Database Characteristics

• A spatial database system is a database system.
• Provides spatial data types and query language in its data model
• Supports spatial data in its implementation, at least with spatial indexing and fast algorithms for spatial joins.

Geographic Database - Types & Functions

• Several attempts have been made to define a superset of geographic data types and processes.
• ISO and OGC standards define core geographic types for use in DBMS and accessing via SQL.

Geometry

• The Geometry class is the root class.
• Includes spatial reference system (e.g., UTM Z 37 N, WGS1984).
• Point, Curve, Surface, GeometryCollection classes are Geometry subtypes.
• Relationships between geometry classes show how geometries are aggregated from one type to another (e.g., LineString is a collection of Points).

Geometry Class Hierarchy

• Shows a hierarchical structure of geometry types.

Boolean Operations

• Used to test spatial relationships between geometries.
• Operators: Equals, Disjoint, Intersects, Touches, Crosses, Within, Contains, Overlaps, Relate

Geographic ORDBMS

• An ideal geographic ORDBMS is extended to support geographic object types and functions through adding features detailed in later slides.

Geographic ORDBMS - Supports and Functions

• Query parser, optimizer
• Query language: handling geographic types (e.g., Points, Polygons) and related functions.
• Indexing services: extended to handle multi-dimensional coordinates (x, y, z, etc.)
• Storage management: handles large volume of various-sized geographic records and relationships.
• Transaction services: handling long geographic transactions.
• Replication services: managing replicated databases and handling changes by distributed users.

Applications of Database Management

• Banking, Manufacturing, Finance, Universities, Airlines, Land administration, water resources management, and Cadaster.

Users in a DBMS Environment

• Application Programmers: Write programs to interact with databases.
• Database Administrators: Manage the entire DBMS system.
• End-Users: Interact with DBMS to conduct various operations (e.g., retrieving, updating, deleting data).

Popular DBMS Software

• Microsoft Access, PostgreSQL, MySQL, SQLite, Oracle, dBASE, FoxPro, IBM DB2, LibreOffice Base, MariaDB, Microsoft SQL Server, etc.

When Not to Use a DBMS System

• Not recommended if budget or expertise isn't available.
• Excel, CSV, and flat files may suffice in such cases.