Databases and Information Management ITSC 1401 Intro to

Databases and Information Management ITSC 1401, Intro to Computers Instructor: Glenda H. Easter Databases and Information Management

Chapter 10 Objectives Explain why data and information are important to an organization Identify data maintenance techniques Differentiate between file processing and databases Discuss the advantages of using a database management system (DBMS) Databases and Information Management 2

Objectives (Continued) Describe the characteristics of relational and object-oriented databases Explain how to use a query language Discuss the responsibilities of the data and database administrators Describe the various types of information systems Databases and Information Management 3

Data and Information Data Collection of items such as words, numbers, images, and sounds that are not organized and have little meaning individually Information Data that is organized Databases and Information Management 4

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Database - Advantages Data Integrity Data Accuracy Data Integration Control of Data dependence Data redundancy Data Security Databases and Information Management 6

What Is a Database? A database is a collection of data files treated as a unit for information retrieval. When data consists of logical files and records, it is said to be “integrated. ” A collection of “integrated” data is defined as a database. Databases and Information Management 7

Data Storage Hierarchy Bits Character (Bytes) Field Record File Databases and Information Management 8

Data Storage Hierarchy (Continued) Bit: Eight bits make one byte or one character. Character: One separate byte that can be a number, a letter, special symbol, or a spacebar. Fields: A group of related characters. Record: A group of related fields. File: A group of related records. Database: A group of related files. Databases and Information Management 9

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Hierarchy of Data (Continued) Data types Text Numeric Currency Date Memo Hyperlink Object Databases and Information Management 11

Hierarchy of Data (Continued) Key field (primary key) Data file (file) Records Databases and Information Management 12

Maintaining Data Adding Records Changing Records Deleting Records Databases and Information Management 13

Maintaining Data Adding Records Databases and Information Management 14

Maintaining Data (Continued) Changing Records Databases and Information Management 15

Maintaining Data (Continued) Deleting Records Databases and Information Management 16

Data Validation Comparing data to a set of rules to determine if the data is accurate. Databases and Information Management 17

Data Validation (Continued) Alphabetic/numeric check Completeness check Range check Consistency check Check digit Databases and Information Management 18

File Processing Versus Databases File Processing Systems Each department has its own set of files Disadvantages • Data redundancy • Isolated data Databases and Information Management 19

File Processing Systems Databases and Information Management 20

The Database Approach Many applications use the data in a single shared database Databases and Information Management 21

Database Approach (Advantages and Disadvantages) Advantages Reduced data redundancy Improved data integrity Shared data Reduced development time Easier reporting Disadvantages: Cost and vulnerability Databases and Information Management 22

Advantages of Databases Data Sharing: Information from one department of an organization can be shared with others. Data Security: Passwords can be used to prevent access to databases from unauthorized users. This might involve requiring passwords to access data, and making data read-only to certain users. Databases and Information Management 23

Advantages of Databases (Continued) Eliminates Data Redundancy or eliminates the repetition of the same data in different files. There are fewer files to manage. If several departments have access to the same database files, management of resources is more efficient. Data Integrity deals with the consistency of information in all applications. Changes made in data will be consistent throughout all related files. Databases and Information Management 24

Disadvantage of Databases (Data Dependence) Data dependence could result in incompatible information. This might occur when data files from different applications are incompatible and cannot be linked. Databases and Information Management 25

Processing Environment –vsthe Database Environment Databases and Information Management 26

The Database Approach Databases and Information Management 27

File Processing –vs- Databases and Information Management 28

Database Management Systems Software or a set of programs designed to control access to the database and manage data resources efficiently Available for various sizes and types of computers Databases and Information Management 29

Database Management Systems Databases and Information Management 30

DBMS Software DDL DML Query Language Report Generator Schema Field Name Field Length Type Query: Who was the first female astronaut? Databases and Information Management 31

The Parts of Database Management Software (DBMS) To produce a printed report or search for specific field values, you have to know which type of data is stored in each field. Database management system software is made of: data dictionary language data manipulation language query language Databases and Information Management 32

Data Dictionary This contains a description of the structure of the data used in the database. It describes: field names size of fields type of data to be stored in field (text, number, logical, date, image) Databases and Information Management 33

Data Dictionary Stores data about each file in the database and each field within those files Databases and Information Management 34

Data Maintenance and Retrieval Query language Databases and Information Management 35

Query Language This is an easy-to-use language understandable to most users. The most widely used query language is Structured Query Language (SQL). This is made up of commands which direct the computer to fulfill the access needs of the user in searching, displaying, updating, and printing records in a database file. “find last name=‘Chicago’”. Partial specification of a field using a ‘wildcard’ character: “find author=johns*” Queries are usually case sensitive. Databases and Information Management 36

Query-by-example (QBE) Databases and Information Management 37

Forms (Data Entry Forms) Databases and Information Management 38

Data Manipulation Language Microcomputer programs generally have a set of commands (either command-line interface or menu-based). These commands enable the user to create a database (adding fields or certain data types) and also to add, delete, and modify records and query and generate reports. Databases and Information Management 39

The Report Generator Microcomputer file management systems allow the user to arrange the report by clicking fields, graphic elements, and page headings dragging them into place and selecting a format for each. Databases and Information Management 40

Report Generator (Report Writer) Databases and Information Management 41

Using Database Software ØFinding information D Øbrowse view Ølist view Øqueries ØStructured Query Language (SQL) Learn SQL online at “Introduction to Structured Query Language, ” an online tutorial. Databases and Information Management 42

Database Security Passwords User Call-Back Systems Routine Backups Databases and Information Management 43

Data Security Access privileges Examples • Read-only • Full-update Databases and Information Management 44

Security of Databases Since so many users are accessing electronic databases, keeping them secure has been a very vital issue. Constant efforts must be made to keep users from tampering with or misusing databases. One major concern is with preventing unauthorized users from gaining access to a database and launching a computer virus that could invade programs and databases, as well as destroy data. Databases and Information Management 45

Protecting Your Privacy Security of databases is becoming a bigger issue as technology advances. Security features include having the physical presence of guards in areas where confidential databases are maintained. Protective measures include requiring identification checks, and storing backup tapes of disks of all valuable information in another location. Databases and Information Management 46

Backup and Recovery Make backups (copies) on a regular basis Logs Before image After image Recovery utilities Rollback Rollforward Databases and Information Management 47

Types of Database Software File Management Programs Database Management Systems Hierarchical Network Relational Object-Oriented Databases and Information Management 48

File Management or WINFILE C: Games Word. Proc Personal Diary School Data. Base CDs BBCards Recipes Drawing Photos Databases and Information Management 49

File Management Programs can work with only one file at a time. File management programs are less complex and inexpensive. They create flat files. Flat files can access records either sequentially, randomly, or sorted. Flat files cannot be linked to data in other files. This is a major disadvantage of them. They do not use key fields or indexes to refer to other files. Databases and Information Management 50

Database Management Systems Database management systems can work with several separate files at a time. The database management system uses one of the four database structures to link files: hierarchical databases network databases relational databases object-oriented databases Databases and Information Management 51

Relational Databases Relation or table (file) Row (record) Attribute or column (field) Relationships Databases and Information Management 52

Relational Databases This is the most flexible type of database organization. Elements are stored in different tables which consist of rows and columns. A table is called a relation. All related tables must have a common data item or a key field. Databases and Information Management 53

Relational Databases Structured Query Language (SQL) Keywords and rules used to implement relational algebra operations Databases and Information Management 54

Database Management Systems (Object-Oriented) Sound Video Text Graphics Animation Databases and Information Management 55

Relational Databases (Continued) Databases and Information Management 56

A common field existing in any two tables creates a relationship between the tables. For instance, a Customer ID Number field in both a customers table and an orders table links the two tables. The relational database structure is the most prevalent in today's organizations Databases and Information Management 57

Object-Oriented Databases Objects contain both data and the activities to read or manipulate the data Examples Multimedia database Groupware database Computer-aided design Hypertext database Databases and Information Management 58

Object-Oriented Databases contain graphics and/or sound. Object-Oriented databases concentrate on the use of objects in the database and provide operations on those objects. Databases and Information Management 59

Object-Oriented Databases -– Hypertext Databases and Information Management 60

Database Management Systems (Hierarchical) Parent Elements Child Elements Databases and Information Management 61

Hierarchical Databases This type of organization is similar to a hierarchical chart of a business organization. Fields or records in a hierarchical database are structured in nodes. The node itself can be a parent or a child to another node. Each segment can only have one parent. Databases and Information Management 62

Hierarchical Databases and Information Management 63

Network Databases Network databases have a structure similar to hierarchical databases, except child nodes or elements can have more than one parent (node) or element. For this reason, the network database may provide more than one way to reach the same element. Additional connections between parent nodes and child nodes are called pointers. Databases and Information Management 64

Database Management Systems (Network) n. Parent Elements n. Child Elements Databases and Information Management 65

Database Administration Role of the Data and Database Administrators Designing databases Creating and maintaining data dictionary Security Performance Backup and recovery Databases and Information Management 66

Database Administration (Continued) Role of the user Become familiar with the data Specify additions to the database Databases and Information Management 67

Creating and Using a Database Defining the Structure Entering Data Designing a Form Databases and Information Management 68

DBMS Tips Design Carefully Define Data Use Forms or Templates Use Report Writer Features Use Queries Use Relational Characteristics Databases and Information Management 69

Database Design Guidelines Careful design to make it easier for users to query and modify the database and create reports Databases and Information Management 70

Creating and Using a Database applications allow non-programmers to use the database through pre-written, generalpurpose programs. In a database, a field must be defined with a record number, a name, a field length, and a type. Some databases allow calculation fields which include formulas. Forms can be designed to make data entry easy or to display on those fields that a user needs to see. Databases and Information Management 71

Database Design Guidelines Databases and Information Management 72

Qualities of Valuable Information Accurate information Verifiable Timely information Organized information Meaningful information Cost-effective information Databases and Information Management 73

How Managers Use Information Planning Organizing Leading Controlling Databases and Information Management 74

Qualities of Valuable Information Levels of Users Executive management Middle management Operational management Nonmanagement employees Databases and Information Management 75

Level of Users Databases and Information Management 76

Types of Information Systems Information systems Collection of hardware, software, data, people and procedures designed to generate information Databases and Information Management 77

Office Information Systems Enhance workflow Facilitate communications Office automation Databases and Information Management 78

Transaction Processing Systems Capture information generated during and organization’s day-to-day transactions Recording an activity Confirming an action or triggering a response Maintaining data Online transaction processing (OLTP) Databases and Information Management 79

Management Information Systems Generates accurate, timely, and organized information Management reporting system (MRS) • Detailed information • Summary information • Exception information Databases and Information Management 80

Decision Support Systems Help users reach a decision Internal data sources Executive information systems Databases and Information Management 81

Executive Information System (EIS) Databases and Information Management 82

Expert Systems Capture and store knowledge of human experts Imitates human reasoning and decision-making process Knowledge base Inference rules Artificial intelligence (AI) Databases and Information Management 83

Databases Database Concepts: The Essentials What’s a good Database System? Using Database Software Types of Database Programs The Internet Connection: Going Public with Databases and Information Management 84

Database Concepts: The Essentials Database äcollection of information stored in an organized way äcan consist of one or more files Database file ämade up of records äunit of information about something Databases and Information Management 85

Database Concepts: The Essentials Records äorganized into distinct fields D Field äseparate area to store a certain type of information Explore the world of computer databases at Look. Smart’s Databases page. Databases and Information Management 86

Database Management Systems enables users to create database tables and provides multiple users with access to data. Databases and Information Management 87

Types of fields (Laura’s record contains several fields) (One file is made up of Laura’s, Bill’s and Peter’s records) Databases and Information Management 88