Introduction to Spatial Databases and DBMS

Introduction to Spatial Databases

• Spatial databases store information about spatial locations, relationships, and shapes of geographic features. Attributes also describe these features.

Fundamental Database Concepts

• Database Management Systems (DBMS) are the underlying framework of information systems, fundamentally changing organizational operations.
• Database systems remain an active area of research with many significant problems.

File Based System

• The precursor to DBMS was the file-based system.
• A collection of application programs that provide services, mostly report generation, for end-users.
• Each program defines and manages its own data.
• Although an improvement over manual filing, significant problems include data redundancy and program dependence.

Database Approach

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

Application Programs

• An application program interacts with the database by sending a request (usually a SQL statement) to the DBMS.
• The DBMS defines a collection of application programs that interact with the database and the DBMS itself.

DBMS Functionality

• Provides a Data Definition Language (DDL) that lets users define the database.
• Provides a Data Manipulation Language (DML) letting them insert, update, delete, and retrieve data.
• Controls access to the database using security, integrity, concurrency, and recovery mechanisms.
• Provides a user-accessible catalog and view mechanism to simplify data.

Components of the DBMS Environment

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

DBMS vs. Flat File

Advantages of the Database Approach

• Control of data redundancy.
• Data consistency.
• Data sharing.
• Improved security and integrity.

Disadvantages of the Database Approach

• Complexity.
• Cost.
• Reduced performance.
• Higher impact of failure.

DBMS Advantages

• Provides various techniques and functions for efficient data storage and retrieval.
• Serves as an efficient handler for multiple applications using the same data.
• Provides uniform administration procedures for data management.
• Application programmers are not exposed to data details.
• Offers data integrity and security.
• Schedules concurrent access to data.
• Reduces application development time.

DBMS Disadvantages

• High hardware and software cost.
• Complex systems requiring user training.
• Data integration may cause issues (problems from electric failure or database corruption) if not well integrated and managed properly.
• Sharing programs may lead to data loss.

Spatial Database Characteristics

• A complete set of information regarding the spatial location, relationship, shape, topological, and geographic features, described by attributes.
• Spatial data types (SDTs) are supported.
• Spatial indexing and efficient algorithms for spatial joins are provided.

Geographic Database Types & Functions

• Standards (ISO and OGC) define types for representing and processing geographic data in databases.
• Core geographic types are defined for use in DBMS and SQL access.

Geometry Data Types

• Geometry class is the root class.
• It has an associated spatial reference (coordinate system and projection (e.g., UTM Z 37 N, WGS1984)).
• Subtypes like Point, Curve, Surface, and GeometryCollection exist.
• Geometry relationships (e.g., LineString as a collection of Points) are further noted.

Geometry Class Hierarchy

• The example diagram shows a hierarchy of geometry types, subtypes, and relations in a database.

Boolean Operations

• Used to test spatial relationships between geometries.
• Including Equals, Disjoint, Intersects, Touches, Crosses, Within, Contains, Overlaps, and Relate operations.

Boolean Operations – Specific Examples

• Equals: Are the two geometries the same?
• Disjoint: Do the geometires share a common point?
• Intersects: Do the geometries intersect?
• Touches: Do the geometries intersect only at their boundaries?
• Crosses: Do the geometries overlap (e.g., lines and polygons)?
• Within: Is one geometry completely within another?
• Contains: Does one geometry fully contain another?
• Overlaps: Do the geometries overlap (must be the same dimension)?
• Relate: Are there intersections between the interior, boundary, or exterior of the geometries?

Advantages of Spatial Databases

• Consolidating data reduces redundancy and lowers maintenance costs.
• Data independence allows applications to use and evolve separately.
• User knowledge can be easily transferred between applications.
• Sharing data provides a corporate view for managers and users.
• Security and data access standards are easier to establish and enforce.
• DBMS are better suited for managing a large number of concurrent users with large data sets.

Disadvantages of Spatial Databases

• DBMS software acquisition and maintenance costs are often high.
• DBMS complexity makes training a necessary factor, especially in smaller projects.
• User performance, especially for complex data types, is better for file-based systems.
• Geographic databases have become larger and more complex in recent years.

Database Management Systems (DBMS)

• DBMS software organizes, manages, and gives access to data efficiently.
• Simple, small-user databases can be stored on standard computer files
• Larger, complex databases need DBMS software for proper management and data integrity.

DBMS Provided Functionality

• Data model -- methods to digitally represent real-world objects
• Data loading capability -- simple and standardized tools for effective bulk data loading, to accommodate various formats
• Indexes -- speed up data searches
• Query language -- support SQL allowing queries on several aspects
• Security -- control access, like read-only for casual users
• Controlled updates -- transaction management to handle coordinated changes among multiple users
• Backup and recovery -- procedures for fail-safety measures
• Database administration tools -- for managing databases

DBMS Provide:

• Applications -- standard and general purpose software tools to create data and user interfaces. API's to create more specific applications
• Application Programming Interfaces (APIs) -- for creating custom applications for specialized uses

DBMS Applications

• Common examples for using a DBMS include banking, manufacturing, finance, universities and airlines, land administration, water resources, and cadastre (land registry).

Users in a DBMS Environment

• Application programmers write programs to interact with the database.
• Database administrators manage the whole DBMS system.
• End-users interact with the database for operations like retrieval and updates.

Popular DBMS Software

• A list of some commonly used DBMS software, for example Microsoft Access, PostgreSQL, MySQL, SQLite, Oracle, dBASE, FoxPro, IBM DB2, LibreOffice Base, MariaDB, Microsoft SQL Server.

When Not to Use a DBMS

• When budget or expertise is lacking for proper DBMS use.
• Alternative solutions like Excel, CSV, or other flat file systems may suffice in those cases.

Types of DBMS

• Relational DBMS (RDBMS) -- organizing data in tables; widely used in GIS
• Object DBMS (ODBMS) -- stores complex objects; addresses weaknesses of RDBMS
• Object Relational DBMS (ORDBMS) -- combines features of RDBMS and ODBMS

Geographic ORDBMS

• An ORDBMS with extensibility framework for geographic objects and functions.
• Support for geographic types, like polygon, points to support query optimization.
• Indexing and Storage management for larger volumes of geographic data.
• Transaction services that deal with long complex transactions, common in GIS applications.
• Replication services to handle distributed users' changes for geographical databases.

Queries on Geographic ORDBMS

• Query parser -- interprets SQL in conjunction with geographic operations.
• Query optimizer -- optimizes queries for geographic types.
• Query language -- supports handling of geographic data types and functionalities.
• Indexing services -- extended for multi-dimensional data like x,y,z coordinates.

This quiz explores the essential concepts of spatial databases and Database Management Systems (DBMS). Understand the evolution from file-based systems to the database approach, and learn about the challenges and advantages associated with these systems. Ideal for students looking to grasp foundational database knowledge.