SQL DataBase HandWritten PART 1

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SQL DATABASE 
PART-4 
1 What is Database ?_ 
A database is an Orqanized collection Of data, 
Stored and xetxieved digitally fyom remote 
Ox lOcal computex sustem. Databases can be 
vast and complex, and such databases are 
developed using flxed design and modeling 
approaches 
TUL LUmar LinKEDIN) 
NOTES qLLEZY CTE LEGRAM). Nhat is DBMS ? 
DBMS stunds fov Data base Management Sustem. 
DBMS is a system software xesponsible fox the 
creation, etrieval, updationand management 
of the database It ensuxes that ouy data is 
Consistent osqanized and easily accessible 
by seyving as an interface between th e data basel| 
and its end-useYs ox appücation so Ftuaxe 
3.What is RDBMS? How is it diffexent fyom DBMS? 
RDBMSStands for Relationgl Data base Management| 
Sustem The key difference heye Compare d to 
DBMS is that RDBMS Stoxes data in the fovm 
of 9 collection of tables , nd xelations can be 
defined betueen the common elds of these 
tables Most Modeyn database management Sustem 
Ke MyS0L, Micyosoft sQL SeYueY, Oyacle IBM 
DB2, and Amazon Redshift aye bQsed on RDBMS 
ATuL HumR (uNKEDIN) 
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STUL AUmaR CLINKEDIn). 
NOTES ymLE Ry (TELEURAM). 4 Ahat is SaL 2 
SOL stands fox Styuctuxed ueyy Lanqugge It is 
the Stand@xd lanquaae used to maintain the 
xelationall database and pex form_many diffexent 
data manipulation Operations on the data- SGL-
was initiatly invented in 191O It is a dgtabase 
tanguage used foy database CYeation deletion 
Fetching and modi fying xows,etc Sometimes, it 
is pxonounced asSequel We can also use it 
hand le oyqanized datq comprised of entities 
Vayiables) and yelations between different entities 
of the data 
to 
5lhat is difference between SQL and MySGL? 
SCL MySOL 
MySQL is a database SOL is G Standayd 
languaqe which stands 
For Structure d Quexy 
Languaqe)based on the 
Engiish Language 
manaqement Sustem. 
SOL fs the core Of the 
elational datQbase 
INhich is used for 
accessing and managing Such As SQL Seyvey, 
dara bases 
MysQL is an_ RDBMS 
LRelational Database 
Management System) 
In foxmix etc. 
ATULHOYmar urKEDIn) 
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6 Alhen SOL appeared? 
SCL Exst appeayed in 1974 is one of the most 
used lanqu ages for maintaining the relationa 
database In_986, SQL became the standayd 
Of the American National Stan dayds nstitute 
ANSI) and ISo (Inteynation al Oxgan'zation for 
Standardization) in 19831 
ATUL KUmeR LinKEDIN) 
NOTES CGALLERY (TELELRAM). 1What îs q Self Join? 
A Seif -oin iS q tupe of join that can be used 
fo connect fo0 fableS As Q esult, if is Q UnaXy 
xelationshîp. Each xOw of the table is a attach ed 
to itself and al1 other ons of the same table 
in a self-join As q esult a self-join is mostly 
used to combine Qnd Compaxe_ OWS_fYom the 
Same data basetable. 
8 What Qre the usaQes of SOLY 
SOL iS_ Yesponsible_for maintaining the yelational dqta 
and the datg styuctu res present in the database 
Some of Common usages are aiven belowN: 
To execure queries aoajnst Q database 
Toxetrieve data fyom a doata base 
To insexts yecords fn a data base 
To updgtes ecords fyom a database 
To delete yecords fom a_data bas e. 
To Cveate new databases 
To cyegte neu tables în a database 
To Create views in databa se 
T6 pexfo Ym conmplex operation s on the data base 
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G.hat axe Tables andFields? 
lables A toble is an Orqanized cO11ection of 
data stOxed in the foYm of yoNs and 
Columns Colunmns can be cateQorized as 
vextica1 and 0S gs horizontal 
Eields he columns in G table are called FieldSs 
hile the xons can be yefermed to 9s 
xecoyds. ATUt KUTMAEtUNKEDx 
NOTES CaALLEKYTELELR ANM). 
10.List the diffevent tupes of yelationships in SOLY 
Theye are different types of yelations In he 
database 
One-to-One t his is q Connection between two 
tables in which egch xecoyd in one table 
COYresponds to the maximum of one 
Yecord in the othey 
One-fo-Many and Many to: 0ne This is the most 
fyequent connection n hich a ecoyd in_ one 
toble is tinked to several yecoyds in another 
Many to-Many-This is used when_definino a 
Yelationship that yequires seveyai instances 
On each side 
Seif-RefeYencIng Relarionshlgslhena table has to 
declare a connection ulth its elP this is 
the method tO employ 
AruL ki0m (LINKEDIN). 
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