Computer fundamentals Computer fundamentals Database Management System 1212022

Computer fundamentals Computer fundamentals Database Management System 1/21/2022 www. Assignment. Point. com 1

Data and Information Computer fundamentals Computer fundamentals • How are data and information related? Step 2. The computer extracts the member • Data is raw facts data from disk. • Information is data that is organized and meaningful receipt Computers process data Step 1. The member into information Ø data, including a photograph, is entered and stored on the hard disk. 1/21/2022 processing data stored on disk Step 3. The receipt is created and printed. www. Assignment. Point. com 2

Data and Information Computer fundamentals Computer fundamentals • What is a database? Collection of data organized so you can access, retrieve, and use it Database software allows you to Create database Add, change, and delete data 1/21/2022 Database software also called database management system (DBMS) Sort and retrieve data www. Assignment. Point. com Create forms and reports 3

What is DBMS? Computer fundamentals Computer fundamentals • A set of programs is provided to facilitate the users in organizing, creating, deleting, updating, and manipulating their data in a database. All these manipulation form a Database Management System (DBMS). 1/21/2022 www. Assignment. Point. com 4

Data and Information Computer fundamentals Computer fundamentals • What is data integrity? Ø Garbage in Degree to which data is correct § 1/21/2022 Garbage in, garbage out (GIGO)—computer phrase that means you cannot create correct information from incorrect data www. Assignment. Point. com Garbage out Data integrity is lost 5

Data and Information Computer fundamentals Computer fundamentals • What are the qualities of valuable information? Accurate Verifiable Timely Organized Accessible Useful Cost-effective 1/21/2022 www. Assignment. Point. com 6

The Hierarchy of Data Computer fundamentals Computer fundamentals • What is a hierarchy? Ø Database contains files, file contains records, record contains fields, field contains characters 1/21/2022 www. Assignment. Point. com 7

The Hierarchy of Data Computer fundamentals Computer fundamentals • What is a field? Ø Ø 1/21/2022 Combination of one or more characters Smallest unit of data user accesses § Field size defines the maximum number of characters a field can contain § Field name uniquely identifies each field § Data type specifies kind of data field contains www. Assignment. Point. com 8

What are common data types? Computer fundamentals Computer fundamentals Text (also called alphanumeric)—letters, numbers, or special characters Currency dollar and cent amounts or numbers containing decimal values Yes/No (also called Boolean)— only the values Yes or No (or True or False) 1/21/2022 Numeric numbers only Auto. Number unique number automatically assigned to each new record Date Memo month, day, year, and sometimes time lengthy text entries Hyperlink Web address that links to document or Web page www. Assignment. Point. com Object (also called BLOB for binary large object)—photograph, audio, video, or document created in other application such as word processing or spreadsheet 9

The Hierarchy of Data Computer fundamentals Computer fundamentals • What is a record? Group of related fields Key field, or primary key, uniquely identifies each record 1/21/2022 www. Assignment. Point. com 10

The Hierarchy of Data Computer fundamentals Computer fundamentals • What is a data file? Ø Collection of related records stored on disk • records 1/21/2022 • Member • ID 2295 • • 2928 • Shannon • • 3376 • Adrian • • 3928 • Jonah • Valesque • z Weinberg • • 4872 • Marcus • Green key field • First Name Donna • Last Name Vandenb erg Murray • Address • City • 1029 Wolf Avenue 33099 Clark Street 15 Duluth Street P. O. Box 45 • • Montgome • ry Prattville • • Clanton • 22 Fifth Avenue • Auburn • • • S t a A t. L A e L A L A L fields www. Assignment. Point. com 11

Maintaining Data Computer fundamentals Computer fundamentals • What is file maintenance? Ø Procedures that keep data current Adding records Changing records Deleting records 1/21/2022 www. Assignment. Point. com 12

Maintaining Data Computer fundamentals Computer fundamentals • Why do you add records? Ø Add new record when you obtain new data 1/21/2022 www. Assignment. Point. com 13

Maintaining Data Computer fundamentals Computer fundamentals • Why do you change records? Ø Ø Correct inaccurate data Update old data 1/21/2022 www. Assignment. Point. com 14

Maintaining Data Computer fundamentals Computer fundamentals • Why do you delete records? Ø Ø When record no longer is needed Some programs remove record immediately, others flag record 1/21/2022 www. Assignment. Point. com 15

Maintaining Data Computer fundamentals Computer fundamentals • What is validation? Ø Ø Process of comparing data with a set of rules to find out if data is correct Reduce data entry errors and enhance data integrity before program writes data on disk 1/21/2022 SAMPLE VALID AND INVALID DATA • Validity Check • • Alphabetic Check • • Numeric Check • • Range Check • • • Consistency Check • • Completeness • Check • Field • Being Checked First • Name Valid Data • Invalid Data Adrian • Ad 33 n • 3 rto 9 Postal Code • 36109 Monthly Fee Date Joined Training Date Last Name • $39. 50 • $95. 25 • 10/20/ • 2005 10/27/ 2005 Valesq uez 10/20/2 005 10/13/2 005 www. Assignment. Point. com • 16

Maintaining Data Computer fundamentals Computer fundamentals • What are the types of validity checks? Check Digit number(s) or character(s) appended to or inserted into a primary key value to confirm accuracy of primary key value 1/21/2022 Alphabetic/ Numeric Check ensures correct type of data entered Completeness Check verifies that a required field contains data Range Check determines whether number is within specified range Consistency Check tests for logical relationship between two or more fields www. Assignment. Point. com 17

File Processing Versus Databases Computer fundamentals Computer fundamentals • What is a file processing system? Each department or area within organization has own set of files Records in one file may not relate to records in any other file May have weaknesses Data redundancy— same fields stored in multiple files 1/21/2022 www. Assignment. Point. com Isolated data —data stored in separate files so it is difficult to access 18

File Processing Versus Databases Computer fundamentals Computer fundamentals • What is the database approach? Ø Ø Many programs and users can share data in database Secures data so only authorized users can access certain data 1/21/2022 www. Assignment. Point. com 19

File Processing Versus Databases Computer fundamentals Computer fundamentals • What are the strengths of the database approach? Reduced data redundancy Improved data integrity Shared data Easier access 1/21/2022 www. Assignment. Point. com Reduced development time 20

File Processing Versus Databases Computer fundamentals Computer fundamentals • How do a database application and a file processing application differ in the way they store data? 1/21/2022 www. Assignment. Point. com 21

Database Management Systems Computer fundamentals Computer fundamentals • What are popular database management systems (DBMSs)? 1/21/2022 • Database • Manufacturer • Computer Type • Access • • • Microsoft Corporation IBM Corporation Personal computer, server, PDA Personal computer, midrange server, mainframe • DB 2 • Informix • IBM Corporation • Personal computer, midrange server, mainframe • Ingres • • Personal computer, midrange server, mainframe • Oracle • Computer Associates International, Inc. Oracle Corporation • Personal computer, midrange server, mainframe, PDA • SQL Server • • Server • Sybase Microsoft Corporation Sybase Inc. • Personal computer, midrange server, PDA • • www. Assignment. Point. com 22

Database Management Systems Computer fundamentals Computer fundamentals • What is a data dictionary? Ø Contains data about each file in database and each field within those files 1/21/2022 www. Assignment. Point. com 23

Database Management Systems Computer fundamentals Computer fundamentals Step 1. Select the fields you want • What is a query? Ø Ø to display in the resulting query. Request for specific data from a database Query language consists of simple, English-like statements that allow users to specify data to display, print, or store Step 2. Assign a name to the query, so you can open it later. Step 3. View query on the screen. 1/21/2022 www. Assignment. Point. com 24

Database Management Systems Computer fundamentals Computer fundamentals • What is a query by example (QBE)? Ø Program retrieves records that match criteria entered in form fields Ø Has a graphical user interface that assists users with retrieving data Query by example screen criteria Query results 1/21/2022 www. Assignment. Point. com 25

Database Management Systems Computer fundamentals Computer fundamentals • What is a form? Ø Window on screen that provides areas for entering or changing data in database Ø Used to retrieve and maintain data in a database Ø Form that sends data across network or Internet is called e-form, short for electronic form 1/21/2022 www. Assignment. Point. com 26

Database Management Systems Computer fundamentals Computer fundamentals • What is data security? Access privileges define activities that specific user or group of users can perform DBMS provides means to ensure only authorized users can access data Read-only privileges user can view data, but cannot change it 1/21/2022 www. Assignment. Point. com Full-update privileges user can view and change data 27

Database Management Systems Computer fundamentals Computer fundamentals • What are backup and log? Ø Backup is a copy of the entire database Ø Log is a listing of activities that change database contents § 1/21/2022 DBMS places three items in log: before image, actual change, and after image before image change after image www. Assignment. Point. com 28

Data model Computer fundamentals Computer fundamentals • A database model defines the manner in which the various files of a database are linked together. The four commonly used database models are : » Hierarchical Databases » Network Databases » Relational Databases » Object-oriented databases 1/21/2022 www. Assignment. Point. com 29

Relational, Object-Oriented, and Multidimensional Databases Computer fundamentals Computer fundamentals • What is a data model? Ø Rules and standards that define how database organizes data Ø Defines how users view organization of data Ø Three popular data models § Relational § Object-oriented § Multidimensional 1/21/2022 DATA MODELS FOR POPULAR DBMSs www. Assignment. Point. com 30

Relational, Object-Oriented, and Multidimensional Databases Computer fundamentals Computer fundamentals • What is a relational database? Ø Ø Ø Stores data in tables that consist of rows and columns § Each row has primary key § Each column has unique name Stores data relationships Uses specialized terminology DATA TERMINOLOGY 1/21/2022 www. Assignment. Point. com 31

Relational Database Computer fundamentals Computer fundamentals • A relational database, the data elements are organized in the form of multiple tables with rows and columns. • Each table of the data base is stored as a separate file, and each row a data record (also known as a tuple). • The data in one table (or file) is related to data in another table with a common field. 1/21/2022 www. Assignment. Point. com 32

Hierarchical Databases Computer fundamentals Computer fundamentals A Parent element Organization Personal Dept Manger Staff Finance Dept Manger Staff Technical Dept Manger Engineers Techni cians Staff A child element 1/21/2022 www. Assignment. Point. com 33

Network Databases Computer fundamentals Computer fundamentals College English khaled Bangla Lailun Jasmine Maths Karim Computer science Shown Rajas An example of a network database 1/21/2022 www. Assignment. Point. com 34

Object-oriented database Computer fundamentals Computer fundamentals • The hierarchical, network, and relational database models were developed for the conventional business data processing applications, such as inventory control, payroll, employee information system, and so on. • Attempts to make use of these database models in a wide variety of other types of applications, exposed several serious shortcomings of these database models. 1/21/2022 www. Assignment. Point. com 35

Relational, Object-Oriented, and Multidimensional Databases Computer fundamentals Computer fundamentals • What is an object-oriented database (OODB)? Stores data in objects Advantages Object is item that contains data, as well as actions that read or process data § Can store more types of data § Can access data faster Often uses object query language (OQL) 1/21/2022 www. Assignment. Point. com 36

Database Management Systems Computer fundamentals Computer fundamentals • What is a recovery utility? Uses logs and/or backups to restore database when it is damaged or destroyed 1/21/2022 Rollforward— DBMS uses log to re-enter changes made to data-base since last save or backup §Also called forward recovery Rollback— DBMS uses log to undo any changes made to database during a certain period of time §Also called backward recovery www. Assignment. Point. com 37

Relational, Object-Oriented, and Multidimensional Databases Computer fundamentals Computer fundamentals • What is a relationship? Ø Connection within data 1/21/2022 www. Assignment. Point. com 38

Relational, Object-Oriented, and Multidimensional Databases Computer fundamentals Computer fundamentals • What is Structured Query Language (SQL)? Ø Ø Allows you to manage, update, and retrieve data Has special keywords and rules included in SQL statements SQL statement results 1/21/2022 www. Assignment. Point. com 39

Relational, Object-Oriented, and Multidimensional Databases Computer fundamentals Computer fundamentals • What are examples of applications appropriate for an object-oriented database? Multimedia databases Groupware databases Store images, audio clips, and/or video clips Computer-aided design (CAD) databases Hypertext databases Store data about engineering, architectural, and scientific designs Hypermedia databases Contain text links to other documents Web databases Contain text, graphics, video, and sound 1/21/2022 Store documents such as schedules, calendars, manuals, memos, and reports Link to e-form on Web page www. Assignment. Point. com 40

Relational, Object-Oriented, and Multidimensional Databases Computer fundamentals Computer fundamentals • What is a multidimensional database? Stores data in dimensions Multiple dimensions, also called hypercube, allow users to analyze any view of data Can consolidate data much faster than relational database 1/21/2022 www. Assignment. Point. com 41

Relational, Object-Oriented, and Multidimensional Databases Computer fundamentals Computer fundamentals • What is a data warehouse? Huge database system that stores and manages data required to analyze historical and current transactions Quick and efficient way to access large amounts of data Uses multidimensional databases 1/21/2022 Often uses a process called data mining to find patterns and relationships among data Data mart is smaller version of data warehouse www. Assignment. Point. com 42

Web Databases Computer fundamentals Computer fundamentals • What is a Web database? Ø Database you access through the Web by filling in a form on a Web page Ø Usually resides on a database server, a computer that stores and provides access to a database 1/21/2022 www. Assignment. Point. com 43

Web Databases Computer fundamentals Computer fundamentals • How might a search engine interact with a Web database? Step 1. Browser sends search text to Web server. 1/21/2022 Step 2. Web server sends Step 3. Web search text through a CGI script to database. Database retrieves list of hits that contains search text and sends it through CGI script back to Web server sends list of hits to browser. www. Assignment. Point. com 44

Database Administration Computer fundamentals Computer fundamentals • What are guidelines for developing a database? » 1. Determine the purpose of the database 2. Design the tables § Design tables on paper first § Each table should contain data about one subject 4. Determine the relationships among the tables 1/21/2022 3. Design the records and fields for each table § Be sure every record has a unique primary key § Use separate fields for logically distinct items § Do not create fields for information that can be derived from entries in other fields § Allow enough space for each field § Set default values for frequently entered data www. Assignment. Point. com 45

Database Administration Computer fundamentals Computer fundamentals • What is the role of the database analyst and administrator? Database analyst (DA) § Focuses on meaning and usage of data § Decides proper placement of fields, defines relationships, and identifies users’ access privileges 1/21/2022 Database administrator (DBA) § Creates and maintains data dictionary, manages database security, monitors database performance, and checks backup and recovery procedures www. Assignment. Point. com 46

Main Components of a DBMS Computer fundamentals Computer fundamentals • The four major components of a DBMS are : » Data Definition Languages (DDL) » Data Manipulation Languages (DML) » Query Language, and » Report Generator. 1/21/2022 www. Assignment. Point. com 47

Data Definition Languages (DDL) Computer fundamentals Computer fundamentals • A Data Definition Languages (DDL) is used to define the structure of a database. The database structure definition is commonly known as database schema. 1/21/2022 www. Assignment. Point. com 48

Data Manipulation Languages (DML) Computer fundamentals Computer fundamentals • The Data Manipulation Languages (DML) includes all the commands that enable the users to enter and manipulate the data. 1/21/2022 www. Assignment. Point. com 49

Query Language Computer fundamentals Computer fundamentals • The Query Language enables users to define their requirements for extracting the desired information from the database in the form of queries. 1/21/2022 www. Assignment. Point. com 50

Database Management Systems Computer fundamentals Computer fundamentals • What is a report generator? Ø Ø Allows user to design a report on screen, retrieve data into report design, then display or print reports Also called report writer 1/21/2022 www. Assignment. Point. com 51

Summary of Database Management Computer fundamentals Computer fundamentals How data and information are valuable assets to an organization Methods for maintaining high-quality data Advantages of organizing data in a database Various types of databases Assessing the quality of valuable information 1/21/2022 Role of the database analysts and administrators www. Assignment. Point. com 52