Lecture 2 INSY 3304 - 002
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This 5 page Class Notes was uploaded by loveena Cherukunnathu on Monday January 25, 2016. The Class Notes belongs to INSY 3304 - 002 at University of Texas at Arlington taught by Karen Scott in Spring 2016. Since its upload, it has received 54 views. For similar materials see Database Management Systems in Information technology at University of Texas at Arlington.
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Date Created: 01/25/16
January 25 2016 Database Svstems Design Implementation and Management Tenth Edition Chapter 1 Database Svstems 0 Evolution of File System Data Processing 0 Contents of each file folder are logically related We have a logically relations to each folder ex customer is sold products which are in an inventory it s all connected 0 Manaalfile systems This is the old system It s hard to organize all the data when its larger People might not alphabetize or put files back in properly Manual file systems work for data repository for small data collections 0 Computerized file systems Early on the people that converted were called data processing specialized AKA DP specialized they converted manual systems to computerized systems They wrote the application created the programs dealt with maintain the system 0 Based on manual systems In the Early days as the number of data files increased there were more application that had to be created You had applications for each type of data and then both needed to communicate to each other With computers you can filter them in anyway u want ex by zipcode but with manual system if you need to have it by zipcode you will have to take all the data and manually change each one o More data more applications Each file used its own application program to store retrieve and modify its data FIGURE 39l 5 Queue CfHONE meanness e ae V amaue ageuoue V TP am sen auras a samaa maesaeeta 23918 Funk Ra Babs Tn 35123 Leah F Hahn s1 seeaaauaa T1 Teena meanhzmz Lanna K Dunne Hausa123a Elan 12s Fan Kr sagas Alas a may usage112 T1 25am 15Jan 2u12 Kathy 1n amnh amass2235 125 Oak Ln nabs Th1 35123 Leah F Hahn 511 sues21o 32 15am 29Jan2u13 13am F ulnwahi smeararea a1 Laa Ln E1ahaThI 35123 Leah F Hahn B lEBBE DM 31 3mm Tenant21312 human orlanan 515 222 1532 Ban 1111 Mew TN 35155 ulna a run ensues 12119 T1 1mm as Dac ma Ann E1 senan T391aaaaaas1 33 Tran Eu Fan Kr 252113 John T Clkun sassaassas T2 seam aasapama Jarues e IEiruurn smear122E a1 Tye Pd Nash Th1 atria Leah F Hahn armsasama 31 12am serumsum George Williams 5152902553 TIES Maple Nash TN 119 John T Dkun 5151235589 31 250010 Wow20112 Anus rs Farriaa T1sae 2r1Tes a11s Elrn eraaa K1 2513 Alan a rain Tunas 12119 Ta 1mm ua oaa au olaua 1lt amnh smearanus are h1ain Nash Th1 3T11s John T man sasaaaesas a snare 14Mar2313 CNAME 2 Customer name 2 Agent name CPHDNE Z ustumer phone APHDNE Agent phone CADDRESS Customer address TP lnsurauee type CZF Customer zip rode AMT 2 insurance policy amount in thousands of HEN insurance renewal date SOU RICE Course TedlmnlngyFCengage learning EX of a content of customer file Flat file2dimensional Nowadays everything is stored in a single repository managing different types of data 39 Basie Fille Terminology DEFINITION Data Raw lasts sIueh as a telephene number a hirth elate a customer name and a yeartetlate WTD sales value ata have little meaning unless they have been erganizecll in some lingieal rnanner Field A Character er green at Characters alphabetic er numeric that has a specific meaning a iieltll is used tn deli rte ant stere ciata Reeendl A legieally reenneetetl set ef ene er mere fields that deserihes a persem place er thing Fer example the fields that ennstitute a eustnmer reenrd might ennsist at the customer s name actdress phene number date Inf birth credit limit and unpaid balance File A enllleetinn ef related reenrds Fer example a file might eentain data about the students currently enrelled at Gigantie U hittersits Field attributeproperty refers to the initial filing system specific characteristic of it Record wowtuple represents a part of an entity personplacething File table FIGURE 17 Sales department EX of older system 0 Problems with File System Data Processing 0 Improvement over manual system File system was improvement from the manual system Ex More way to categorize 0 Extensive programming A lot of programming for the file system though especially if there is lots of data Didn t have add on hot query like they have now Systems reports was complex and complicated Limited security Any changes needed to make was difficult 0 Structural and Data Dependence Old system had structural dependence and data dependence Structural dependence access to file is dependent to its own structure ex if you need to addremove attribute then you were required changes the program to access it Structural independence you can change the file structure without affecting data access code Data dependence data access has to change When the data storage characteristics change Data independence data access doesn t have to change When storage changes Logical data how a person views the data conceptual Physical data it s the format on how the computer works with the data ex where in the diskcircuit it is File system programs you have to point very directly specify You needed to specify file type record specifications and all field definition 0 Data Redundancy File system structure makes it di icult to combine data If u have multiple files then it s harder to keep it protected Organizational structure promotes storage of same data in di erent locations Redundant data that becomes inconsistence data Inconsistency If there are multiple copies of data and they don t match each other Redundancy Same data stored unnecessarily multiply times Data anomalies Abnormality that occurs When redundant data is not updatedchanged properly Update update data in one place but it doesn t update in every place that data exists Insertion When you add new data ex customer is added to one place not another in marketing s data but not in sale s data Deletion When you delete in one place and not the other ex marketing deleted the customer but sales still has it on its file 0 Design and DataModeling Data design is really important so we need really good data modeling skills Datamodeling tools There are lots of tools out there that helps you all the way through the design process Datamodeling skills Even if you have good tools if you don t know how to use it then there is no use So you need to have the skills you should know how to use your tools What is data modeling Facilities communication between designer user and developer Also lays out the structure for the database 0 Database Systems 0 Database system single repository Old le wasn t single repository now it is Sometimes it s just Viewed that way Database system consist of data that is logically related in a single storage repository We have data itself and we have DBMS 0 What is stored Current system stores data structure the relationship among data and access paths to the data DBMS allows u to define store manage all data access paths and data components FIGURE 18 A Database System V Personnel dept Database Employees Customers Sales Inventory Accounts Sales dept and Accounting dept Personnel dept Sales dept Accounting dept ilall ma Wm SOURCE CourseTechnologyCengage Learning Figure 18 People 9 who use the system 9 then people who use the database in the backend 0 The Database System Environment 0 Database system defines and regulates collection storage management and use of data 0 Five major parts of a database system 1 People 2 Data 3 Proceduresbusiness rules DBMSapplication programs handle it 4 Hardware 5 Software DBMSfrontend applicationDLLAPI Procedures and slandards Application programs
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