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954245 Chapter 1 Introduction to Database Management
Modern Management and Information Technology Collage of Arts, Media and Technology Chiang Mai University
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Outline The Need for Databases Hierarchy of Data
Types of Enterprise Data Storage Components of Database System DBMS Architecture
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What is a database ? Give examples of databases What is a database ?
A collection of files storing related data Give examples of databases Accounts database; payroll database; UW’s students database; Amazon’s products database; airline reservation database
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What is a database management system?
Give examples of databases management system Well-known DBMSs include MySQL, PostgreSQL, Microsoft SQL Server, Oracle, Sybase, SAP HANA, and IBM DB2. In 2006, Oracle: 47% market share, $7.2BN in sales IBM: 21% market share with $3.2BN in sales Microsoft: 17% market with $2.6BN in sales
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1. The Need for Databases Database Applications:
Banking: transactions Airlines: reservations, schedules Universities: registration, grades Sales: customers, products, purchases Online retailers: order tracking, customized recommendations Manufacturing: production, inventory, orders, supply chain Human resources: employee records, salaries, tax deductions Databases can be very large. Databases touch all aspects of our lives
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University Database Example
Application program examples Add new students, instructors, and courses Register students for courses, and generate class rosters Assign grades to students, compute grade point averages (GPA) and generate transcripts
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History of Database Management
Paper-based Paper Box card index Filling File-based System (Computerized) Magnetic tap file, Magnetic disk, Hard disk Server
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History of Database Systems
1950s and early 1960s: Data processing using magnetic tapes for storage Tapes provided only sequential access Punched cards for input Late 1960s and 1970s: Hard disks allowed direct access to data Network and hierarchical data models in widespread use Ted Codd defines the relational data model Would win the ACM Turing Award for this work IBM Research begins System R prototype UC Berkeley begins Ingres prototype High-performance (for the era) transaction processing
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History of Database Systems
Research relational prototypes evolve into commercial systems SQL becomes industrial standard Parallel and distributed database systems Object-oriented database systems 1990s: Large decision support and data- mining applications Large multi-terabyte data warehouses Emergence of Web commerce Early 2000s: XML and XQuery standards Automated database administration Later 2000s: NoSQL and NewSQL Giant data storage systems Google BigTable, Yahoo PNuts, Amazon, ..
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2. Hierarchy of Data
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Database Concept
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Hierarchy of Data Bit (Character) - a bit is the smallest unit of data representation (value of a bit may be a 0 or 1). Eight bits make a byte which can represent a character or a special symbol in a character code. Byte- a unit of digital information that most commonly consists of eight bits to encode a single character, for example: which is binary number to represent A Field - a field consists of a grouping of characters. A data field represents an attribute (a characteristic or quality) of some entity (object, person, place, or event).
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Hierarchy of Data Record - a record represents a collection of attributes that describe a real-world entity. A record consists of fields, with each field describing an attribute of the entity. File - a group of related records. Files are frequently classified by the application for which they are primarily used (employee file). A primary key in a file is the field (or fields) whose value identifies a record among others in a data file.
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Hierarchy of Data Database - is an integrated collection of logically related records or files. A database consolidates records previously stored in separate files into a common pool of data records that provides data for many applications. The data is managed by systems software called database management systems (DBMS). The data stored in a database is independent of the application programs using it and of the types of secondary storage devices on which it is stored.
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3. Types of Enterprise Data Storage
Computer data storage in earliest era Each department store their own data Increasing of stored data causes data redundancy File-based System A database contains an organized collection of data which each of the data is related to one another. This data is used to handle operational functions of the organization and is kept systematically at the central data storage. So, it can be shared which is useful for management and efficient data retrieval. Database System
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Question File- based System Database System
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Question File- based System Database System
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File-based System A file based system is a collection of application programs that perform services for the users wishing to access information. Each program within a file based system defines and manages its own data. A file based system is a collection of application programs that perform services for the users wishing to access information. Each program within a file based system defines and manages its own data. Because of this, there are limits as to how that data can be used or transported. File based systems were developed as better alternatives to paper based filing systems. By having files stored on computers, the data could be accessed more efficiently. It was common practice for larger companies to have each of its departments looking after its own data. The problems that arise with this type of file based system are listed below: Data separation and isolation Data dependence Data duplication Incompatible data (different file formats) Lack of flexibility in organising and querying the data Increased number of different application programs
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Old File Processing Systems at Pine Valley Furniture Company
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Computer System for Pine Valley Furniture Company
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File-based System Advantages Suitable for small system Simply
Easy to design and implement Less of data Disadvantages Data separation/ isolation Data duplication/ redundancy Data dependence Data inconsistency Fixed queries
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Database System Advantage Disadvantage Minimized data inconsistency
Reduced data redundancy Sharing data Accurate and reliable data Use the same standard Security Greater independence of the data and programs Disadvantage Have higher costs of hardware, software, and others Complexity from the application programs and users High risk and high impact of system failure
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4. Components of Database System
Hardware Software Data People Procedure A database management system (DBMS) consists of several components. Each component plays very important role in the database management system environment. The major components of database management system are: Software Hardware Data People Procedures
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Hardware Hardware refers to all of the system’s physical devices
For example, computers (PCs, workstations, servers, and supercomputers), storage devices, printers, network devices (hubs, switches, routers, fiber optics),and other devices (automated teller machines, ID readers, and so on).
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Software Operating system software DBMS software
Microsoft Windows, Linux, MacOS, UNIX, and MVS. DBMS software Microsoft’s SQL Server, Oracle Corporation’s Oracle, Sun’s MySQL, and IBM’s DB2. Application programs and utility software Although the most readily identified software is the DBMS itself, to make the database system function fully, three types of software are needed: operating system software, DBMS software, and application programs and utilities. a. Operating system software: manages all hardware components and makes it possible for all other software to run on the computers. Examples of operating system software include Microsoft Windows, Linux, MacOS, UNIX, and MVS. b. DBMS software: manages the database within the database system. Some examples of DBMS software include Microsoft’s SQL Server, Oracle Corporation’s Oracle, Sun’s MySQL, and IBM’s DB2. c. Application programs and utility software: Are used to access and manipulate data in the DBMS and to manage the computer environment in which data access and manipulation take place. Application programs are most commonly used to access data found within the database to generate reports, tabulations, and other information to facilitate decision making. Utilities are the software tools used to help manage the database system’s computer components. For example, all of the major DBMS vendors now provide graphical user interfaces (GUIs) to help create database structures, control database access, and monitor database operations.
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Data The most important component of the DBMS
Databases are defined, constructed and then data is stored, updated and retrieved to and from the databases. The database contains both the actual (or operational) data and the metadata (data about data or description about data).
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People/ Users System administrators Database designers System analysts
Programmers End users People/ Users -System administrators oversee the database system’s general operations. -Database administrators, also known as DBAs, manage the DBMS and ensure that the database is functioning properly. -Database designers design the database structure. They are, in effect, the database architects. If the database design is poor, even the best application programmers and the most dedicated DBAs cannot produce a useful database environment. Because organizations strive to optimize their data resources, the database designer’s job description has expanded to cover new dimensions and growing responsibilities. -System analysts and programmers design and implement the application programs. They design and create the data entry screens, reports, and procedures through which end users access and manipulate the database’s data. -End users are the people who use the application programs to run the organization’s daily operations. For example, salesclerks, supervisors, managers, and directors are all classified as end users. High-level end users employ the information obtained from the database to make tactical and strategic business decisions.
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Procedures Procedures refer to the instructions and rules that help to design the database and to use the DBMS. The users that operate and manage the DBMS require documented procedures on hot use or run the database management system. These may include. Procedure to install the new DBMS. To log on to the DBMS. To use the DBMS or application program. To make backup copies of database. To change the structure of database. To generate the reports of data retrieved from database.
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Database Access Language
Used to access the data to and from the database The most popular database access language is SQL (Structured Query Language) Users use the database access language to enter new data, change the existing data in database and to retrieve required data from databases. Database Access Language The database access language is used to access the data to and from the database. The users use the database access language to enter new data, change the existing data in database and to retrieve required data from databases. The user write a set of appropriate commands in a database access language and submits these to the DBMS. The DBMS translates the user commands and sends it to a specific part of the DBMS called the Database Jet Engine. The database engine generates a set of results according to the commands submitted by user, converts these into a user readable form called an Inquiry Report and then displays them on the screen. The administrators may also use the database access language to create and maintain the databases. The most popular database access language is SQL (Structured Query Language). Relational databases are required to have a database query language.
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5. DBMS Architecture External Level Conceptual Level Internal Level
conceptual schema internal schema Database User 1’s view User 2’s view External Level Conceptual Level Internal Level ANSI SPARC is an acronym for the American National Standard Institute Standard Planning and Requirements Committee. A standard three level approach to database design has been agreed. External level Conceptual level Internal level (includes physical data storage) The 3 Level Architecture has the aim of enabling users to access the same data but with a personalised view of it. The distancing of the internal level from the external level means that users do not need to know how the data is physically stored in the database. This level separation also allows the Database Administrator (DBA) to change the database storage structures without affecting the users' views.
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DBMS Architecture A database management system provides three views of the database data: The external level defines how each group of end-users sees the organization of data in the database. A single database can have any number of views at the external level. The conceptual level unifies the various external views into a compatible global view.[31] It provides the synthesis of all the external views. It is out of the scope of the various database end-users, and is rather of interest to database application developers and database administrators.
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DBMS Architecture The internal level (or physical level) is the internal organization of data inside a DBMS. It is concerned with cost, performance, scalability and other operational matters. It deals with storage layout of the data, using storage structures such as indexes to enhance performance. Occasionally it stores data of individual views (materialized views), computed from generic data, if performance justification exists for such redundancy. It balances all the external views' performance requirements, possibly conflicting, in an attempt to optimize overall performance across all activities.
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Database languages are special-purpose languages, which do one or more of the following:
Data definition language (DDL)– defines data types and the relationships among them Data manipulation language (DML)– performs tasks such as inserting, updating, or deleting data occurrences Query language – allows searching for information and computing derived information
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QUESTIONS?
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Report PowerPoint presentation: 25-30 slides
Big data and Hadoop NoSQL Internet of things Cloud computing Social media Mobile application
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References Hoffer, J.A., Ramesh, v., and Topi, H. (2013). Modern Database Management. 11th ed. ISBN x.php onents%20of%20database%20system%20environment.pdf
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