Good morning! APR2101 Business Information and Communication
Database Systems, Data Centers, and Business Intelligence Chapter 5 Principles of Information Systems, Eleventh 2 Edition
Why Learn About Database Systems and Business Intelligence? • Database : – Organized collection of data • Database management system (DBMS) : – Group of programs that manipulate the database – Provide an interface between the database and its users and other application programs • Database administrator (DBA) : – Skilled IS professional who directs all activities related to an organization’s database
Data Management • Without data and the ability to process it: – An organization could not successfully complete most business activities • Data consists of raw facts • To transform data into useful information: – It must first be organized in a meaningful way
The Hierarchy of Data [bit]
Data Entities, Attributes, and Keys • Entity : – A person, place, or thing for which data is collected, stored, and maintained • Attribute : – Characteristic of an entity • Data item : – Specific value of an attribute
Data Entities, Attributes, and Keys (continued)
The Database Approach • Traditional approach to data management: – Each distinct operational system uses data files dedicated to that system • Database approach to data management: – Pool of related data is shared by multiple application programs
The Database Approach (continued)
Data Centers, Data Modeling and Database Characteristics • When building a database, an organization must consider: – Content : What data should be collected and at what cost? – Access : What data should be provided to which users and when? – Logical structure : How should data be arranged so that it makes sense to a given user? – Physical organization : Where should data be physically located?
Data Center • Climate‐controlled building or set of buildings that house database servers and the systems that deliver mission‐critical information and services • Traditional data centers: – Consist of warehouses filled with row upon row of server racks and powerful cooling systems
Data Center (continued) • Many organizations now use large shipping containers packed with racks of servers and cooled to easily connect and set up • Businesses and technology vendors working to develop green data centers that run more efficiently and require less energy for processing and cooling • Backup and security procedures for data centers can be a concern
Data Modeling • Data model : – Diagram of data entities and their relationships • Enterprise data modeling : – Starts by investigating the general data and information needs of the organization at the strategic level • Entity‐relationship (ER) diagrams : – Data models that use basic graphical symbols to show the organization of and relationships between data
Simplified ER Diagram for a library Customer Nr. Customer-Nr. Customer Name Date Address borrowed Author-Nr. Name Book-Nr. Book Author written Title
The Relational Database Model • Relational model : – Describes data using a standard tabular format – Each row of a table represents a data entity (record) – Columns of the table represent attributes (fields) – The domain is the range of allowable values for data attributes
The Relational Database Model (continued) • Manipulating data: – Selecting : • Eliminates rows according to certain criteria – Projecting : • Eliminates columns in a table – Joining : • Combines two or more tables – Linking : • Manipulating two or more tables that share at least one common data attribute
The Relational Database Model (continued) • Data cleanup – Process of looking for and fixing inconsistencies to ensure that data is accurate and complete – Database normalization is often used to clean up problems with data
Database Management Systems • Creating and implementing the right database system ensures that the database will support both business activities and goals • Capabilities and types of database systems vary considerably
Overview of Database Types • Flat file – Simple database program whose records have no relationship to one another • Single user – Only one person can use the database at a time – Examples: Access, FileMaker Pro, and InfoPath • Multiple users – Allow dozens or hundreds of people to access the same database system at the same time – Examples: Oracle, Microsoft, Sybase, and IBM
Providing a User View • Schema : – Used to describe the entire database – Can be part of the database or a separate schema file • DBMS : – Can reference a schema to find where to access the requested data in relation to another piece of data
Providing a User View: Schema
Creating and Modifying the Database • Data definition language (DDL) : – Collection of instructions and commands used to define and describe data and relationships in a specific database – Allows database’s creator to describe data and relationships that are to be contained in the schema • Data dictionary : – Detailed description of all the data used in the database
Creating and Modifying the Database (continued)
Storing and Retrieving Data • One function of a DBMS is: – To be an interface between an application program and the database • Concurrency control – Method of dealing with a situation in which two or more people need to access the same record in a database at the same time
Storing and Retrieving Data
Selecting a Database Management System Important database characteristics to consider: – Database size – Database cost – Concurrent users – Performance – Integration – Vendor
Popular Database Management Systems (continued) • Database as a Service (DaaS) : – Emerging database system – Database administration is provided by the service provider – The database is stored on a service provider’s servers and accessed by the client over a network
Using Databases with Other Software • DBMSs can act as front‐end or back‐end applications: – Front‐end applications interact directly with people – Back‐end applications interact with other programs or applications
Databases and Application Servers End-user Application Access Databases Server Internet Application servers manage the process of connecting users to data • set up an application session • check each user’s identification and password • fetch requested information from the appropriate database • build the data into a Web page for display to the users
Big Data Applications • Deals with large amounts of unstructured data from the Internet, photos, video, audio, social networks, and sensors • Special big data hardware and software can be more effective than traditional relational DBMSs • Some people have concerns that organizations are harvesting huge amounts of personal data
Data Warehouses, Data Marts, Data Mining
Data Warehouses, Data Marts, and Data Mining (continued) • Predictive analysis : – Form of data mining that combines historical data with assumptions about future conditions to predict outcomes of events – Used by retailers to upgrade occasional customers into frequent purchasers – Used to predict future sales up to a year in the future
Distributed Databases • Distributed database : – Database in which the data may be spread across several smaller databases connected via telecommunications devices – Gives corporations more flexibility in how databases are organized and used • Replicated database : – Holds a duplicate set of frequently used data
Distributed Databases
Enjoy your break!
Welcome back! Telecommunications and Networks
An Overview of Telecommunications • Telecommunications is the electronic transmission of signals for communications • Telecommunications medium is any material substance that carries an electronic signal to support communications between a sending and receiving device • Networking protocol is a set of rules, algorithms, messages, and other mechanisms that enable software and hardware in networked devices to communicate effectively
An Overview Of Telecommunications Telecommunications devices relay signals between computer systems and transmission media
Communication vs. Communications Sender Receiver Message Channel Feedback
An Overview of Telecommunications • Communications can be synchronous or asynchronous – Synchronous communications: receiver gets message instantaneously – Asynchronous communications: receiver gets message after some delay
Basic Telecommunications Channel Characteristics • Simplex channel: – Transmits data in only one direction • Half‐duplex channel: – Transmits data in either direction, but not simultaneously • Full‐duplex channel: – Permits data transmission in both directions at the same time
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