Transcript Chapter 5 Lecture 2

Chapter 5 Lecture 2
Objectives
• Understand Data definition language (DDL) and data
dictionary
• Learn about popular DBMSs
• Understand types of Data Warehouses
• Conceptually understand ODBC
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Creating and Modifying the Database
• Data definition language (DDL)
• A collection of instructions and commands used to define
and describe data and data relationships in a specific
database
• Allows the database’s creator to describe the data and the
data relationships that are to be contained in the schema
and subschemas
• Data dictionary: a detailed description of all the data
used in the database
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Figure 5.11: Using a Data Definition
Language to Define a Schema
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Figure 5.12: A Typical Data
Dictionary Entry
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Storing and Retrieving Data
• When an application program request data from DBMS,
the application program follows a logical access path
• When the DBMS goes to a storage device to retrieve the
requested data, it follows a path to the physical location
(physical access path) where the data is stored
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Figure 5.13: Logical and Physical Access
Paths
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Manipulating Data and
Generating Reports
• Data manipulation language (DML): the commands
that are used to manipulate the data in a database
• Structured Query Language (SQL): adopted by the
American National Standards Institute (ANSI) as the
standard query language for relational databases
• Once a database has been set up and loaded with data, it
can produce reports, documents, and other outputs
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Table 5.6: Examples of SQL Commands
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Popular Database Management
Systems
• Popular DBMSs for end users include Microsoft’s Access
and Corel’s Paradox
• The complete database management software market
includes databases by IBM, Oracle, and Microsoft
• Examples of open-source database systems: PostgreSQL
and MySQL
• Many traditional database programs are now available on
open-source operating systems
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Selecting a Database Management
System
• Important characteristics of databases to consider:
• Size of the database
• Number of concurrent users
• Performance
• The ability of the DBMS to be integrated with other
systems
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Selecting a Database Management
System (continued)
• Important characteristics of databases to consider
(continued):
• Features of the DBMS
• Vendor considerations
• Cost of the system
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Database Applications: Linking the
Company Database to the Internet
• Corporate databases can be accessed by customers,
suppliers, and company employees through:
• The Internet
• Intranets
• Extranets
• Semantic Web: a seamless integration of traditional
databases with the Internet
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Data Warehouses, Data Marts, and
Data Mining
• Data warehouse: a database that collects business
information from many sources in the enterprise, covering
all aspects of the company’s processes, products, and
customers
• Data mart: a subset of a data warehouse
• Data mining: an information-analysis tool that involves
the automated discovery of patterns and relationships in a
data warehouse
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Figure 5.17: Elements of a
Data Warehouse
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Table 5.8: Common Data-Mining
Applications
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Business Intelligence
• Business intelligence (BI): the process of gathering
enough of the right information in a timely manner and
usable form and analyzing it to have a positive impact on
business strategy, tactics, or operations
• Knowledge management: the process of capturing a
company’s collective expertise wherever it resides and
distributing it wherever it can help produce the biggest
payoff
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Distributed Databases
• Distributed database
• A database in which the data may be spread across several
smaller databases connected via telecommunications
devices
• Corporations get more flexibility in how databases are
organized and used
• Replicated database: a database that holds a duplicate
set of frequently used data
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Online Analytical Processing (OLAP)
• Software that allows users to explore data from a number
of different perspectives
Table 5.9: Comparison of OLAP and Data Mining
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Open Database Connectivity (ODBC)
• Standards that ensure that software can be used with any
ODBC-compliant database
• Can be used to export, import, or link tables between
different applications
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Figure 5.19: Advantages of ODBC
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Object-Oriented and Object-Relational
Database Management Systems
• Object-oriented database
• Stores both data and its processing instructions
• Method: a procedure or action
• Message: a request to execute or run a method
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Object-Oriented and Object-Relational
Database Management Systems
(continued)
• Object-oriented database management system
(OODBMS): group of programs that manipulate an
object-oriented database and provide a user interface and
connections to other application programs
• Object-relational database management system
(ORDBMS): DBMS capable of manipulating audio,
video, and graphical data
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Summary
• Hierarchy of data: bits, characters, fields, records, files,
and databases
• Entity: a generalized class of things (objects) for which
data is collected, stored, and maintained
• Attribute: characteristic of an entity
• Data model: diagram of entities and relationships
• Relational model: describes data in which all elements
are placed in two-dimensional tables called relations
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Summary (continued)
• Selecting: eliminates rows according to certain criteria
• Projecting: eliminates columns in a table
• Database management system (DBMS): group of
programs used as an interface
• Between a database and application programs
• Database and the user
• Data dictionary: detailed description of all the data used
in the database
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Summary (continued)
• Data warehouse: database that collects business
information from all aspects of a company’s processes,
products, and customers
• Data mining: an information-analysis tool for the
automated discovery of patterns and relationships in a
data warehouse
• Open database connectivity (ODBC) standards: ensure
that software can be used with any ODBC-compliant
database
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