An Introduction to database system
Database Management
COP4540, SCS, FIU

Basic Definitions
• Data: Meaningful facts, text, graphics, images, sound, video segments.
• Database: An organized collection of logically related data.
• Information: Data processed to be useful in decision making.
• Metadata: Data that describes data.
Database Management
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What is a DataBase system?
(DB)
• It is a logically coherent collection of data with inherent meaning.
• It represents a miniworld, and should represent the state of that world accurately.
• It is managed by a database management system (DBMS).
Database Management
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What is a DataBase Management System?
(DBMS)
• A (large) piece of software which provides an interface between the user or application program and the stored data.
• A DBMS is developed according to a particular data model.
• Some example DBMSs are:
– IMS, DB2, Oracle, Sybase, Informix, SQL
Server, Access, FoxPro, O2.
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The functionality of DBMS
• Manages very large amounts of data.
• Supports efficient access to very large amounts of data.
• Supports concurrent access to very large amounts of data.
• Supports secure, atomic access to very large amounts of data.
Database Management
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Several basic concepts
• Data models
– A data model is a way of representing (part of) the world.
– The principle current data model are:
• Hierarchical
• Network
• Relational
• Object-oriented
• E-R
• Semantic
Database Management
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Several basic concepts
• Database design
– Design goals
• Minimize redundancy in order to eliminate the modification anomalies in database.
• Represent the situation accurately
– Design Stages
• Conceptual (product independent)
• Logical (product specific)
• Physical / Implementation (product specific)
Database Management
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Database Development Activities
Enterprise Modeling
Conceptual Data Modeling
Logical DB Design
Physical DB Design
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The stages focused in COP4540
DB Implementation
DB Maintenance
Database Management
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Conceptual Database Modeling
• Determine user requirements.
• Determine business rules.
• Build conceptual data model
– outcome is an entity-relationship diagram or similar communication tool.
Database Management
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Logical Database Design
• Select logical database model.
• Map Entity-Relationship Diagrams
• Normalize data structures.
• Specify business rules.
Database Management
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Physical Database Design
• Select DBMS
• Select storage devices
• Determine access methods
• Design files and indexes
• Determine database distribution
• Specify update strategies
Database Management
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Several basic concepts
• Schema
– Logical structure of the data defined by using data definition language (DDL).
• Queries
– A “query” is a database lingo for a question about the data.
– A “query” is composed by using query language (QL)
Database Management
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The architecture of database system
Users / Programmers
Application Programs / Queries
Database Management System
1. Software to process queries/programs
2. Software to access stored data
Stored data
Database Management
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Components of the Database Environment
• CASE Tools
• Repository
• Database Management System (DBMS)
• Database
• Application Programs
• User Interface
• Database Administrators (DBA)
• System Developers
• End Users
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Evolution of Database Systems
• Hierarchical and Network (Legacy): Data are modeled as linked records.
• Relational: Data are modeled as related tables.
• Object-oriented: Data are organized as linked objects.
– Object-relational: Integration of relational and object-oriented features.
Database Management
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RDBMS and SQL
• RDBMS is a DBMS on the basis of relational model.
• It is the most popular type of the DBMS.
• The data is organized as tables called relations
• Two famous systems:
–
System R at IBM & Ingres at UC Berkeley
• SQL (Structured Query Language)
– the most important query language based on relational model.
Database Management
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RDBMS and SQL
Accounts accountNo balance
12345
67890
1000.00
2846.92
type savings checking
SELECT balance
FROM Accounts
WHERE accountNo = 67890
Result:
2846.92
Database Management
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Disadvantages of File Processing
Systems
• Data Dependence
• Data Redundancy (Duplication of data)
• Limited Data Sharing
• Lengthy Development Times
• Excessive Program Maintenance
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Advantages of Database Approach
• Program-Data Independence: No need to rewrite programs when data is modified
• Minimal Data Redundancy
• Improved Data Consistency
• Improved Data Sharing
• Increased Application Development
Productivity.
Database Management
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Advantages of Database Approach
• Enforcement of Standards
• Improved Data Quality (Constraints)
• Better Data Accessibility/Responsiveness
• Reduced Program Maintenance
• Security, Backup/Recovery, Concurrency
Database Management
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Costs and Risks of the Database
Approach
• New, Specialized Personnel
• Installation Management Cost and
Complexity
• Conversion Costs
• Organizational Conflict
Database Management
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