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Note for Database Management System - DBMS By Bharat Choudhary

  • Database Management System - DBMS
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DBMS Operational Data: - System esa fdlh Hkh izdkj dk Operation Perform djus ds fy;s ,d Set of Instructions ds lkFk dqN Data Input esa fy;s tkrs gSa tks fd Input fd;s x, MkVk dks Process djus ds ckn ,d Required Information dks Output esa Display ;k Save djrs gSaA bl izdkj ls System esa Stored Data esa ls og Data Element tks fd Processing ds fy;s Use esa fy;s tkrs gSa ;k ftu Data ij Operation Perform fd;s tkrs gSa] mu lHkh Data dks Operational Data dgk tkrk gSaA bl izdkj ds Data Hard Disk ;k RAM esa jgrs gSa rFkk Database System esa Operational Data dks Database File esa Store djds j[kk tkrk gSaA File Management Vs Database Management File Management System: - ,sls Computerized System tks fd Information Management ds fy;s Files dks Use esa ysrs gSaA File Management System dgykrk gSaA bl izdkj ds System esa Data Files rFkk ,d Programs dk Group Hard disk Store jgrh gSaA Files ij fdlh Hkh izdkj dk Operation Perform djus ds fy;s ,d vyx Program gksrk gSa rFkk ml File dks Open djds mlesa Modify ;k Read Operation Perform djrs gSaA blesa Data dks Managed j[kus ds fy;s Files dks Read, unit, update o Delete fd;k tkrk gSaA blds fy;s Data Structures dh Help ls ge Hard disk ij Operational Data dh various format dh Files esa Save djds j[krs gSa rfkk izR;sd Operation dks Perform djus ds fy;s gesa Specific Files dks Open djds muesa Stored Data ij Operation djus iM+rs gSaA bl izdkj ds System esa fuEufyf[kr dfe;ka gks ldrh gSa% & 1. Duplicate File Creation 2. Inconsistent between files caused by concurrent operations and system failure. 3. Unsecured data 4. Reading & writing delays 5. File Scattering 6. Program and File dependence 7. lack of maintenance. Database Management System: - Database Management System esa Information Management ds fy;s ,d Database File rFkk ,d Group Software Programs Use esa fy;k tkrk gSaA Database esa Interrelated rFkk Interconnected Data dk Group Store jgrk gSa rFkk fofHkUu izdkj ds Software Programs ml Database esa Stored Data dks mudh Interconnectivity o Relationship dks /;ku esa j[krs gq, Operate djrs gSaA bu Operations esa Database Create djuk mlesa Data dks Delete djuk 'kkfey gksrk gSaA bl izdkj Database esa Stored Data Low level file handling dks Hide djds gesa Tabular Format esa Store Data gh Show djrk gSa ftldks dh Manage o Maintain djuk vis{kkd`r vf/kd vklku gksrk gSaA bl izdkj ds System dks Use esa ysdj File Management System dh cgqr lkjh Drawbacks dks [kRe dj ldrk gSaA Difference between both approaches (1) Data Redundancy: - Redundancy dk eryc Data Unnecessary Duplicacy ls gksrk gSaA File Management System esa fofHkUu izdkj ds Operations ds fy;s Files Write gksrh jgrh gSa rFkk dbZ ckj ,d gh File dh Multiple Copies Hkh Write gks tkrh gSaA bldks Prevent djuk File Management esa Possible ugha gSa rFkk File dks 1

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(2) (3) (4) (5) (6) (7) Manually Delete djus ls Data Lost gksus dk Chance jgrk gSaA ysfdu DBMS esa izR;ssd Operation, Well managed rFkk fofHkUu izdkj dh Constraints ds lkFk gksrk gSaA ftlls fd Data dh Unrequited Duplicacy dks iwjh rjg ls jksdk tk ldrk gSaA Data Inconsistency: - Data dks Usable cuk;s j[kus ds fy;s gesa Data dks Safe State ij j[kuk t:jh gksrk gSaA vFkkZr lHkh Data ds chp dh Relationship o connectivity izR;sd Operation ds ckj Check gksuk t:jh gSaA File Management System esa bl izdkj dh Checking always possible ugha gksrh rFkk Data dks Consistent j[kuk cgqr eqf'dy o Non-ensured gksrk gSaA tcfd Database Management System izR;sd Step ij gesa Database dks Consistency dks Review djus rFkk mls Incosistent gks tkus ij okil Rollback djus dks easy option provide djokrk gSaA ftlls dh gekjk Data always consistent (safe) State ij jgrk gSaA Data Integrity: - Data Integrity dk eryc gksrk gSa fd gekjs }kjk Use fd;k tkus okyk Data Consistent rFkk Accurate gksA Data dks Integrate j[kus ds fy;s Storage ds fy;s Hksts tkus okys Data dks igys Check djuk t:jh gksrk gSaA DBMS esa Centralized check Input fd;s tkus okys Data dks Check djds Integrity dks ensure fd;k tk ldrk gSaA tcfd File Management System esa ge bl izdkj dh Checking required level rd ugh dj ldrs tSls Age ds fy;s integn Input djuk gSa File Management esa ensure djus ldrs gSa ysfdu Age 16-60 rd Input djuh gSa ;g Ensure djuk File Management esa Properly ugha gks ldrkA Atomicity: - Hard disk ij Stored Operational Data dks cgqr lkjs cyers ds }kjk ,d gh le; ij Access fd;k tkrk gSaA bls Concurrent Access dgk tkrk gSaA bu Data values ij operations Hkh concurrent fd;s tkrs gSaA ysfdu dbZ ckj sories of operations ds nkSjku vyx System fail gks tkrk gSa rks og Operation half updation gh dj ikrk gSa tSls Banu esa Money transfer Process ds fy;s First account ls Balance de fd;k tkrk gSa fQj Second account esa Balance increase fd;k tkrk gSaA bu nksuks Operation ds chp System fail gks tkus ij Data dh Integrity o consistency break gks tkrh gSa o Data atomic ugha jg ikrkA System recovery ds ckn Database System esa bl izdkj ds Operation dks fcuk back djds Data values dks atomic ldrs gSa ysfdu File Management System esa Rollbacking djuk eqf'dy gksrk gSa rFkk Data dh Atomicity dks ensure djuk eqf'dy gksrk gSaA Shared Data: - Database System, multiple data access operations dks vius control esa allow djrk gSa rFkk Read vkSj Write conflicts under control solve fd;s tkrs gSaA ogha File System esa lkjh Independent files ij bl izdkj dk control possible ugha gksrk gSaA Security: - fdlh Hkh Organization dk Data muds fy;s Important rFkk confidential gksrk gSa rFkk muds }kjk lnSo lgh desire dh tkrh gSa fd mudk Data lqjf{kr jgs rFkk flQZ Authorized Persons ds }kjk gh access fd;s tk ldsA DBMS esa ;g dke Database Administration ds }kjk authorized o autheticcation o Password Management ls fd;k tkrk gSaA ysfdu izR;sd File ds fy;s centralized password protection possible ugha gksrkA Data Independence: - Data Independence dks nks Parts esa Divide fd;k tkrk gSaA Logical Data Independent o Physical data independence physical data independence ;g ensure djrk gSa fd storage medium esa change gksus ij application program esa change djus dh require ugha gksuh pkfg;s tcfd logical data 2

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independent ;g ensure djrh gSa fd application program dks data esa record ;k failed add djus ds ckn Hkh mu Data dks access djus ds fy;s change djus dh t:jr ugha gSaA (8) Conflict Resolution: - Database management system ,d gh O;fDr (DBA) }kjk Manage fd;k tkrk gSa tks fd multiple users ds conflicts dks nwj dj ldrk gSa tcfd file management system esa ;g possible ugha gSaA 3

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