unit 5 (data manipulation and control - i 1)

8/12/2019 Unit 5 (Data Manipulation and Control - I 1)

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DATA MANIPULATION AND CONTROL - I

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Objectives

At the end of this unit, you will be able to

Lea!n to "!eate, alte! and d!o# database ob$e"ts

Lea!n to inse!t , u#date and delete data

Lea!n to %!ant and !e&o'e #!i&ile%es

Topics

Data Definition (tate)ents

Data Mai#ulation (tate)ents

Data Cont!ol (tate)ents

T!ansa"tion Con!ol (tate)ents

*

+


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Datatypes in Oracle

a"h "olu)n &alue of a table in O!a"le has a dataty#e* The dataty#e asso"iates afied set of #!o#e!ties with the &alue and defines the do)ain of &alues that ea"h "olu)n

"an "ontain* These #!o#e!ties "ause O!a"le to t!eat &alues of one dataty#e diffe!ently

f!o) &alues of anothe!*The followin% dataty#es a!e a&ailable in O!a"le*

Datatype Description

CHAR(size) (to!es fied len%th "ha!a"te! data* Mai)u) si.e is +///*

Default si.e is 1 byte*

VARCHAR2(size) (to!es &a!iable len%th "ha!a"te! st!in%s ha&in% )ai)u)

si.e of 0/// bytes* ou )ust s#e"ify si.e fo! a2ARC3AR+*

NUM!R(p"s) (to!es nu)be! ha&in% #!e"ision # and s"ale s, # "an !an%e

f!o) 1 to 45 and s dete!)ines the nu)be! of di%its to the!i%ht of the de"i)al #oint*

DAT! (to!es data and ti)e &alues between /1-/1-061+ 7C and

/1-1+-061+ AD

#ON$ (to!es la!%e,&a!iable len%th st!in%s,u# to + %i%abytes*

#ON$ RA% (to!es lon% bina!y st!in%s, u# to + %i%abytes*

RA%(size) (to!es s)all bina!y st!in%s,less than +/// bytes*

RO%&D (to!es heade"i)al RO8ID &alues that "o!!es#ond to

O!a"le table RO8ID(*9blo"'*!ow*file:

Data De'inition tateents

Data definition state)ents CRAT,ALTR and DROP a!e used

to "!eate new ob$e"ts, alte! the st!u"tu!es of eistin% ob$e"ts, o!"o)#letely !e)o&e ob$e"ts f!o) the database*

Constraints

Const!aints a!e #a!t of a table definition that li)it the &alues you"an ente! into its "olu)ns* Till now the only !est!i"tion on &alues

that you "ould ente! has been on the dataty#es and si.es of the

&alues ente!ed whi"h ha&e to be "o)#atible with those of the

"olu)ns into whi"h the &alues a!e bein% #la"ed*

8hen you "!eate a table you "an #la"e "onst!aints on the &alues

that "an be ente!ed into its fields; by doin% this (


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Constraint Type Description

NOT NU## This "onst!aint is of "olu)n &a!iety only* The NOT NULL

Constraint 'eywo!d #la"ed i))ediately afte! the dataty#e of a "olu)nensu!es that any atte)#ts to #ut null &alues into that field by inse!t

o! u#date state)ent will be !e$e"ted*

UN&*U! As a "olu)n "onst!aint- The UNI


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ffe"t of @o!ei%n @o! fields defined as @ORIN ?

?ey Const!aint

Any &alues you #ut into these fields with an IN(RT o!

UPDAT "o))and, the &alue )ust al!eady be #!esent in

thei! #a!ent 'eys*

ou )ay #ut NULLBs in these fields unless that field hasNOT NULL "onst!aint*

ou )ay delete any !ows with fo!ei%n 'eys without

affe"tin% the #a!ent 'eys*

As fa! as "han%es to the #a!ent 'ey &alues a!e "on"e!ned, the!e a!e

essentially th!ee #ossibilities

ou "an !est!i"t o! fo!bid the "han%e = whi"h )eans that

the "han%e on the #a!ent 'ey is !est!i"ted*

ou "an )a'e "han%e in the #a!ent 'ey and ha&e that sa)e

"han%e )ade in the fo!ei%n 'ey auto)ati"ally = whi"h

)eans the "han%e "as"ades*

ou "an )a'e "han%e in the #a!ent 'ey and set the fo!ei%n

'ey to NULL auto)ati"ally 9assu)in% NUL( a!e allowedin the fo!ei%n 'ey: = whi"h )eans the "han%e nulls the

fo!ei%n 'ey*

8ith these "ate%o!ies a&ailable, you )ay not want to t!eat all of

the DML "o))ands in the sa)e way*

IN(RT is i!!ele&ant as it #uts new #a!ent 'ey &alue in the table

so none of its &alues "an be "u!!ently be !efe!en"ed*

UPDAT( and DLT( "an be "as"aded o! !est!i"ted as desi!ed*


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Tables

Tables a!e #!i)a!y sto!a%e units in O!a"le*

To sto!e data in a table, the table will ha&e to be "!eated, with the !e>ui!edst!u"tu!e, alon% with the &a!ious "onst!aints*

Create Table

tateent CR!AT! TA#!

+/rpose (to!a%e (t!u"tu!e to hold data*

ysnta0

%1ere

Tablena)e is na)e of the table

Colu)nna)e is na)e of the "olu)nDataty#e is the dataty#e of the "olu)n

Colu)n"onst!aint is data "onst!aint fo! the "olu)nTable"onst!aint is data "onst!aint fo! the tableA( >ue!y "olu)nBs ty#e and si.es a!e "o#ied f!o) the !esult

of A( >ue!y , afte! the table is "!ated the !esults of

the >ue!y a!e inse!ted as its !ows*

!0aple C!eate a new table usin% A( "lause*

*# Coan (


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!0aple To "onfi!) the "ontents of table N8

*# Coan (


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!0aple C!eate a new table

*# Coan (


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%1ere

Tablena)e is na)e of the table*

Colna)e is na)ee of the "olu)n*

Dataty#e is the dataty#e of the "olu)n

Const!aintna)e is the na)e of the "onst!aint

nable"lause is the na)e of the "onst!aint o! all t!i%%e!s

diasble"lause on the table*

!0aple Add "olu)n to table te)#*

*# Coan (


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!0aple To "onfi!) the st!u"tu!e of table te)#*

*# Coan (


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Res/lt Table alte!ed*

!0aple To "onfi!) the st!u"tu!e of table salestab*

*# Coan (


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!0aple To &e!ify the status of all "onst!aints of salestab table*

*# Coan (


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Data Manip/lation tateents

Data Mani#ulation state)ents a!e used to alte! the database tables in so)e way*

The UPDAT, IN(RT and DLT state)ents alte! eisin% !ows in a database table,#la"e new !e"o!ds into a database table o! !e)o&e one o! )o!e !e"o!ds f!o) the database

table*

INSERT

tateent &N!RT

+/rpose Add new !ow9s: to the database table*

ynta0 IN(RT INTO tableG9"olu)nG,"olu)nH**:H2ALU( 9&aluesG,&alueH**: J >ue!yK

%1ere

table is na)e of the table

"olu)n is na)e of the table&alue is the "o!!es#ondin% &alue fo! the "olu)n

2ALU( adds one !ow*

>ue!y adds as )any !ows as sele"ted by the >ue!y*

!0aple To des"!ibe the st!u"tu!e of e)# table*

*# Coan (


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Inserting null values implicitly

!0aple Inse!t a new e)#lo#yee, but only assi%n the e)#loyee nu)be!,

na)e, $ob, de#a!t)ent nu)be! and )ana%e! nu)be!*

*# Coan (


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!0aple Dis#lay all data f!o) table de#t1

*# Coan (ue!y o#tion

*# Coan (


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!0aple Inse!t &alues into "olu)ns usin% #a!a)ete!s*

*# Coan (


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*# Coan (


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!0aple To !eali.e the effe"t of the !ollba"', "o))it and sa&e#oint"o))ands*

*# Coan (


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%1ere

Table is na)e of the table to be u#dated

Colu)n e#! sets fields in the s#e"ified "olu)n to the&alue of e#!*

9"olu)n,**: sets fields in the s#e"ified "olu)ns to the &alue!etu!ned

9sub>ue!y: by the sub>ue!y*

Condition identifies the !ow9s: to be u#dated*

!0aple Chan%e the "o))ission of e)#loyee 1+40 to and $ob to

(AL(MAN*

*# Coan (


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!0aple Confi!) the "han%es )ade by the abo&e state)ent*

*# Coan (


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!0aple Confi!) the "han%es to the unde!lyin% table )ade by the abo&estate)ent*

*# Coan (


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ynta0

%1ere

Ob$e"t#!i& is an ob$e"t #!i&ile%e to be %!anted

ALL all ob$e"t #!i&ile%es

Colu)n s#e"ifies a "olu)n f!o) a table o! &iew on whi"h#!i&ile%es a!e %!anted

ON identifies the ob$e"t on whi"h #!i&ile%es a!e %!anted

TO identifies use!s to whi"h the ob$e"t #!i&ile%e is

%!antedPU7LIC %!ants ob$e"t #!i&ile%es to all use!s

8IT3 RANT OPTION allows %!antee to %!ant the ob$e"t #!i&ile%es to

othe! use!s

!0aple !ant (LCT #!i&ile%es to s"ott on e)# table

*# Coan (


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!0aple C!eate a synony) fo! e)# table

*# Coan (


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+/rpose Re&o'es database o! syste) o! ob$e"t a""ess #!i&ile%es f!o) use!s*

ynta0

%1ere

CACAD! a!e !e>ui!ed to !e)o&e any @? !efe!en"es

CONTRA&NT )ade to the ob$e"t by )eans of the

R@RNC( #!i&ile%e*

!0aple Conne"t to use!1 s"he)a

*# Coan (


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!!o! in disablin% !oles in #!odu"t use! #!ofile

!0aple Dis#lay the "ontents of de#t table #!esent in use!1 s"he)a

*# Coan (


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1are6!0cl/sive 8hen a use!, U(R1 is a""essin% RCORD1 f!o) the table and

#oc5 U(R+ t!ies to a""ess the anothe! !e"o!d f!o) the sa)e table, thenboth the t!ansa"tions a">ui!e a sha!ed lo"' on the table* If U(R4

t!ies to a""ess RCORD1 and U(R1Bs t!ansa"tion a">ui!es an

e"lusi&e lo"' on the table* This is also !efe!!ed to as !ow-le&ello"'in%, whi"h is a uni>ue featu!e of O!a"le* The abo&e ea)#le

shows how O!a"le handles two diffe!ent u#dates that "ontend fo!

the sa)e !e"o!d of a table*

M/lti7versionin3 O!a"le uses the )e"hanis) of Multi-2e!sionin% to handle >ue!ies,

whi"h "ontend with u#dates to !etu!n a""u!ate !esults* @i!st a

t!ansa"tion does not a">ui!e !ow lo"'s of any ty#e fo! >ue!ies* This)eans that two t!ansa"tions "an issue ea"tly the sa)e >ue!y at

the sa)e ti)e without any "ontention fo! the sa)e set of !ows* In

this "ase fo! e&e!y >ue!y O!a"le !etu!ns a ti)e#oint-based &e!sion

of the data o! a !ead-"onsistent sna#shot that the >ue!y !e>uests*O!a"le ensu!es that e&e!y !ow in a >ue!yBs !esult set is "onsistent at

the ti)e you issue the >ue!y* 3e!e O!a"le uses !ollba"' se%)entfo! its )ulti-&e!sionin% )e"hanis)*

a"h ti)e a use!Bs t!ansa"tion be%ins, O!a"le assi%ns thet!ansa"tion to a !ollba"' se%)ent* @o! the du!ation of a t!ansa"tion,

the asso"iated use! #!o"ess w!ites !ollba"' info!)ation to the

assi%ned !ollba"' se%)ent* 8hen you "o))it a t!ansa"tion, O!a"le

!eleases the !ollba"' info!)ation but does not i))ediately dest!oyit* The info!)ation !e)ains in the !ollba"' se%)ent to "!eate !ead-

"onsistent sna#shot of #e!tinent data fo! >ue!ies that sta!ted befo!e

the t!ansa"tion "o))ited* To %ua!antee that the !ollba"' data isa&ailable fo! as lon% as #ossible fo! su"h &iews O!a"le w!ites the

etents of !ollba"' se%)ent se>uentially*

"oc!

tateent #OC-

+/rpose Pe!)its sha!ed a""ess to the table by )ulti#le use!s while

#!ese!&in% the tableBs Inte%!ity

ynta0

%1ere

Table is the na)e of the table*

+6

LOC? TA7L G, tableHQ

IN (3AR J (3AR UPDAT J CLU(I2 K MOD GNO8AITH


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NO8AIT )a'es LOC? TA7L !etu!n "ont!ol to you so that

you )ay ente! othe! "o))ands while you wait fo!

the table to be"o)e a&ailable*

CLU(I2 #!e&ents othe! use!s f!o) lo"'in% o! u#datin% any

!ow of the table

(3AR Allows othe! use!s >ue!y the table but not )odify it

(3AR UPDAT allows you to u#date !ows of the table while othe!

use!s ha&e !ows lo"'ed

!0aple To lo"' the e)#loyee table in e"lusi&e )ode, but to !etu!n the

"ont!ol if any othe! use! has lo"'ed it*

*# Coan (


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DML state)ents, the t!ansa"tion is fi!st "o))itted, and the

DDL state)ent is ee"uted and "o))itted as a new, sin%le

state)ent t!ansa"tion*

A use! dis"onne"ts f!o) ORACL* 9The "u!!ent t!ansa"tion is

"o))itted:

The!e is an abno!)al te!)ination of a use! #!o"ess* 9The"u!!ent t!ansa"tion is !olled ba"':

Afte! one t!ansa"tion ends, the net ee"utable (


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The s#e"ified sa&e#oint is #!ese!&ed, but all sa&e#oints that we!e

established afte! the s#e"ified one a!e lost*

All tables and !ow lo"'s a">ui!ed sin"e that sa&e#oint that a!e

!eleased,but all data lo"'s a">ui!ed #!e&ious to the sa&e#oint a!e!etained*

The t!ansa"tion is still a"ti&e; it "an be "ontinued*

tateent Rollbac5

+/rpose Rolls ba"' "han%es )ade to the tables in the database sin"e the )ost

!e"ent "o))it*

ynta0 ROLL7AC?

Savepoint

Inte!)ediate )a!'e!s o! sa&e#oints "an be de"la!ed within a t!ansa"tion*(a&e#oints a!e often used to di&ide a lon% t!ansa"tion into s)alle! #a!ts*

Usin% sa&e#oints, you "an a!bit!a!ily )a!' you! wo!' at any #oint within a

lon% t!ansa"tion* This allows you the o#tion of late! !ollin% ba"' wo!'#e!fo!)ed befo!e the "u!!ent #oint in the t!ansa"tion but afte! a de"la!ed

sa&e#oint within the t!ansa"tion*

(a&e#oints a!e also useful in a##li"ation #!o%!a)s in a si)ila! way* If a#!o"edu!e "ontains se&e!al fun"tions, a sa&e#oint "an be "!eated befo!e

ea"h fun"tion be%ins* Then, if a fun"tion fails, it is easy to !etu!n the data

to its o!i%inal state befo!e the fun"tion be%an and then !e-ee"ute thefun"tion with !e&ised #a!a)ete!s o! #e!fo!) a !e"o&e!y a"tion*

Afte! a !ollba"' to a sa&e#oint, the data lo"'s obtained by !olled ba"'state)ents a!e !eleased* Othe! t!ansa"tions that we!e waitin% fo! the

#!e&iously lo"'ed !esou!"es "an #!o"eed* Othe! t!ansa"tions that want to

u#date #!e&iously lo"'ed !ows "an do so*

tateent avepoint

+/rpose Ma!' a sa&e#oint within the "u!!ent t!ansa"tion*

ynta0 (A2POINT

4/


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UMMAR, 97

Data Definition Lan%ua%e 9DDL: is the subset of s>l "o))ands used to )ani#ulateO!a"le database st!u"tu!es, in"ludin% tables*

Tables a!e "!eated usin% CRAT TA7L "o))and*

Const!aints li)it the &alues ente!ed into its "olu)ns* The &a!ious "onst!aints a!e NOT

NULL, UNIue!ies "an also be used in the UPDAT "o))and*

DLT @ROM "o))and is used to delete !ows f!o) a table*

To )a'e the wo!' #e!)anent, COMMIT is used and to dis"a!d the t!ansa"tions, the

ROLL7AC? "o))and is used*

One "an dis"a!d all the "han%es u#to a #oint, defined with the (A2POINT

state)ent*

unit 5 (data manipulation and control - i 1)

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