hibernate (1) notes

8/9/2019 Hibernate (1) notes

1/691

Hibernate:

Hibernate is a frame work. Hibernate frame work is used to develop a

java application to interact with database server.

A frame work is a piece of software this piece of software contains

solutions from commonly repeatedly occurred problems occurs multiple

projects.

IDE (Integrate Development Environment):

As part of IDE all the components all interated.

Ex: Editors! "ompilers! #ervers! $rowser etc.

$y usin IDE we can develop project %uickly.

IDE is will improve the productivity of the developer.

&he followin are the most popular IDE!s.

1. Eclipse'. (y Eclipse). *et $eans+. ,AD -,elational Application Development/. 0 $uilder

&o work with IDE we re%uired a workspace2 folder.

A work space folder contains all the 3les which are related to that

project.

4hen we double click on Eclipse.e5e it will launch a dialo whose nameis work space launch. &o this work space launch we have to supply work

space folder as input.

4hen we start the Eclipse IDE in the work space folder it has created a

folder with the name metadata. &his folder contains all the 3les which

are used by Eclipse IDE.

Eclipse IDE contains set of perspective by default Eclipse IDE launch6s 0EE

perspective.

A perspective contains set of views. A view is a Email window. Aperspective contains set of views.

If we would like to perform any operations in IDE we must create a

project.

Procedure to create the project in IDE:

#tep 1: 3le new project.


2/691

#tep ': select the appropriate project and click on ne5t button.

#tep ): in new java project window enter the project name and click on

3nish.

#tep +: we delete the project with out checkin the check bo5. &he 3les

will not delete permanently.

As part of java prospective we use out line view to see all the variablesand methods which are available in class.

&he packae e5plorer view is used to see all the 3les which are available

in the project.

#elect 7roject 7roperties java $uild path library add

e5ternal jar 3les.

In IDE we can disable auto build process -7roject builds

automatically.Note:

4e can chane the short cuts of Eclipse IDE

-4indow 7references 8eneral 9eys.

As part of a Eclipse IDE we can replace or et the old code by usin

compare with or replace with local history.

&o create a jar 3les we use an option e5port -3les e5port.

Procedure to create web based application:#tep 1: 3le new web project.

#tep ': &he above step will display a dialo with the name ;new web

project6. In that dialo enter the project name make sure that project

name and web root folder name is same.

4hen we work with IDE to con3ure in deployment descriptor we have

two options. &hey are like source and desin. &o see the contents of

web.5ml 3le we can use an option source.

$y usin raphical user interface if we want con3ure servlets. 4e can

use desin view.

4hen we use IDE we no need to deploy the project manually. 4e can

con3ure IDE to deploy the project. As part of 0EE respective. we can use

server view to con3ure the project in IDE.

"trl


3/691

#tep 1: 8et the server view and riht click chooses an option con3ure

server connector.

#tep ': "hoose the appropriate server the home directory of the server.

#ame servers

re%uired user name and password supply these values and click

on =92.#tep ): &o add the project to server we can use an option add

deployment.

#tep +: &hey are some IDE6s are available which are responsible to

interact with database

#ervers. &he popular IDE6s for oracle database server are &=AD

and #>? developer.

@or the database server like (#>? we

can use (#>? workbench2.#tep /: In the companies because of licenses issues we may not use the

IDE like &=AD.

Eclipse ives has provided a feature to interact with database

servers. 4e can use

EclipseB(E"?I7#E to interact with database servers.

Procedures to confgure IDE to interact with database server:

1. =pen (E"?I7#E database e5plorer of prospective.'. In the database browser view when we riht click it lunches a popup

menu from that choose an option new.). &he above step as lunched a window whose name is database

driver from that choose driver template and provide a driver name.

*ow we have to supply driver class! url! username! password to

interact with D$ server.

Hibernate is a rame which is used to interact with database

server:&here are so many frameworks are available in the market there are

some of struts! sprins! 0#@ etc.

1. #truts! sprin frame works are used to develop webCbased

applications.'. Hibernate is a technoloy are a framework which is used to interact

with database server this framework resolves all the problems of


4/691

0D$". In a project if he tries to use hibernate frame work if he

develop the project %uickly.). As part of 0D$" we have to write lot of code to hardly checked

E5ception.+. As part of Hibernate we no need to provide the code to handle

checked E5ception./. If we use 0D$" a prorammer is responsible to reister the driver

and et the connection. 7rorammer must provide the code to close

the connection. As part of Hibernate he is responsible to open the

connection and close the connection.. As part of Hibernate it6s only starts the transaction and ends the

transaction. Hibernate internally uses 0&A -0ava &ransaction A7I. &o

start the transaction and end the transaction.. Hibernate support internal connection provides Hibernate uses ")$

connection pool. D$"7 connection pool. If we went to use e5ternaconnection pool like webCloical we can con3ure it. If we use 0D$"

we have to provide the code to handle database speci3c error code.F. If we use Hibernate we no need to provide the code to handle

database speci3c errors.G. Hibernate supports it6s own %uery lanuae H>? -Hibernate >uery

lanuae to resolve the problems of some java application to

interact with multiple D$ #ervers without chanin the %ueries.

1. In case of 0D$" we have to provide thecode to remove the hard codin. In case of Hibernate we provide

the details in Hibernate con3uration by readin the details from

con3uration 3le -.(?. It will interact with multiple Database

#erver.11. If we use 0D$" prorammer is responsible

to write the code to enerate the primary key values. As part of

Hibernate they have provided preCde3ned class to enerate primary

key values.

1'. $y usin Hibernate we can represent the%ueries in the form of object or we can use criteria A7I. As part of

Hibernate we can achieve polymorphism between the tables and we

can achieve association also.1). by usin 0D$" we can6t transfer result

set object from one proram to another proram -result set can6t be

transferable to resolve this problem we have to provide the code to


5/691

retrieve data from result set object and store it in array list object if

we use Hibernate. Hibernate does all these work.1+. we have the technoloy like E0$ to

interact with D$ #erver we can6t run E0$ Application without E0$

container. 4e can6t use E0$6s in all type of application we can

resolve all these problems we can use Hibernate.

&he followin is true Architecture of Hibernate framework.

Hibernate is called as =,( tool are =,( framework =,( -=bject

,elational (appin.

In the market they are so many =,( frame works are available some of

them ere Hibernate! 07A -java persistent A7I 0D= -java data object i

batches! #&= -service data oBp! &op ?ink etc.

All these frame works are used as =,( &ools. &he diJerences betweenthe &ools are the names of the classes are diJerent.

In the database server the data will be stored in the side the tables

between the tables we establish a relationship because of this reason we

call it is relational data.

Hibernate #B4

0AKA Application

0D$" A7I

D$ #erver


6/691

,epresentations relational records in the form of object we call it has

=,(:

7roduct

can we use 0D$" to represent records in the form of objectL

A. es! we can use 0D$" to represent the records in the form of object.

In case of 0D$" we have to provide hue amount of code torepresent hue amount of data in the form of object.

$. As a Hibernate developer we need to develop a java application

with uses Hibernate A7I and interact with database server. If we

want to develop a java application we need to con3ure D$ server

and provide some additional 3les to Hibernate software.". If the Hibernate software to communicate with database server we

re%uired a user with special privileed -se%uence the tables in the

database server must contain primary keys.

Procedure to create user and assign some privileges:

1. ?oin to database server usin administrative user use the

followin command assin the user and privilees.#>?M create user hib ide3ed br abcN8rant connect! resource to hibN8rant create se%uence to hibN

'. 4e have to create the table with primary key.#>?M create table emp -eno number-+ primary key! ename

varchar'-'!Address varchar'-'N

#>?M create table product -pid number-/! name varchar'-'!

price number-1!'N#>?M alter table product add primary key-pidN

). 4e can et Hibernate software from Hibernate.or

1 7no 1

' pname'

) price

1

7one

1

'

7&wo

'


7/691

+. Hibernate software is a collection of jar 3les the most important jar

3le is Hibernate.jar/. If we want to use Hibernate software we have to develop the

followin ) 3les./.1. Hibernate con3uration 3le

/.'. 0ava $eans -7=0= classes -plain =ld 0ava =bject/.). Hibernate (appin 3les -hbm. Every framework uses con3ure 3le. &his is the startin point to

any framework enerally the con3uration 3les or 5ml 3les-we can

use property 3les also as con3uration 3les. in Hibernate we use Hibernate.cf.5ml as the con3uration 3le we

can chane the con3uration 3le name accordin to re%uirement.F. Hibernate con3ure 3le contains the entire information which is

re%uired to communicate with database server. &hey are:

a. Driver classb. urlc. usernamed. pwde. dialect

Hibernate.cf.5ml

G. Hibernate software re%uired the java proram to represent a record

in the form of object. $ecause of this reason we have to develop

couple of java prorams this is based on the number of tables

available in the database server.1. &hese prorams

contains instance variables! set,ow- and er,ow- methods.

Developin these prorams are easy because of this reason 7=0=

classes are known as -plain old java objects.

driverOclass Poracle.jdbc

url P jdbc.oraQ.

username P hib

password P abc

dialect P =racleDialect

BBinformation about H,( 3les


8/69


9/691

1. (ust contain a default constructor.'. (ust be placed inside a packae.). &he 7=0= class supports properties. A set,ow- and et,ow-

methods are called as properties.+. 4hen the Hibernate people are developin software they are

started usin the help of other software6s. &hey are like &ransactionA7I! "onnection &ool! Dom 7arse! cache jar 3les. If we would like to

run the Hibernate software are need to make sure that all these jar

3les enerate the "?A##7A&H other wise Hibernate software will fail

to run.

Hibernate #B4

QQQ.. Etc

7rocedure to con3ure the Hibernate software and enerate Hibernate

con3uration 3le by usin (yEclipse IDE.

I. #tart (yEclipse IDE pointin to works place folder.II. "on3ure (yEclipse IDE to interact with the D$ #erver.-create D$

$rowserIII. "reate a java project and add the packae to it.IK. Add Hibernate capabilities to the above project. (yEclipse

project capabilities Hibernate capabilities.

K. "hoose the re%uired jar 3les to be added. -"ore library and

notations.

Hibernate).jar

0&A.ja

r

")7.j

ar

Dom.j

ar"ache.jar


10/691

KI. "hoose new Hibernate con3uration option and click on ne5t

button. @rom the list of available D$ Driver select to which database

server we have to connect.KII. "hoose the packae name and provide the class name as =,A#@

and click on 3nish button.

Procedure to generate hbm fles and P"#" classes:

#tep 1: 8o to (yEclipse db e5plorer perspective and establish the

connection with Database server.

#tep ': #elect the all re%uired tables and riht click on it enerates T

launch popCup menu from that choose on option Hibernate reverse

Enineerin.

#tep ): #elect src and packae and check the 3rst ) check bo5es and

click on 3nish button launches abstract class.

#tep +: &he followin is the con3uration is Hibernate con3uration 3le.

UhibernateC"on3urationM

U#essionC@actoryM

Uproperty name P "onnection.driverOclass2M

oracle.jdbc.driver.=racleDriver

UBpropertyM

Uproperty name P "onnetion.url2M

jdbc:oracle:thin:Tlocalhost:1/'1:5eUBpropertyM

Uproperty name P "onnection.username2MhibUBpropertyM

Uproperty name P dialect2Mor.hibernate.dialect

=racleGiDialectUBpropertyM

Umappin resource P infoBinetsolvBproduct.hbm.5ml2BM

Umap resource P infoBinet#olvBEmp.hbm.5ml2BM

UB#essionC@actoryM

UBhibernateCcon3urationM BB #ave hibernate.cf.5ml

#tep /: &he followin is the 7=0= class of emp tables.

public class EmpR


11/691

private Inteer enoN

private #trin nameN

private Double salaryN

BB provide setters and etters methods

above instance variables.

S BB #ave Emp.java

#tep : &he followin on the tas of Employee 3le.

Uhibernate mappinM

Uclass name P info.inetsolv.Emp2 table P Emp2M

Uid name P eno2 type P java.lan.Inteer2M

Ucolumn.name P E*=2 presission P s2BM

Uenerator class P assined2BM

UBidMUproperty name P name2 type P java.lan.#trin2M

Ucolumn name P *A(E2BM

UBpropertyM

Uproperty name P salary2 type P java.lan.Double2M

Ucolumn name P #A?A,2BM

UBpropertyM

&he followin are the most important interfaces and classes.Interaces:

1. or.hibernate.#ession@actory'. or.hibernate.#ession). or.hibernate.&ransaction+. or.hibernate.>uery/. or.hibernate."riteria

$lasses:

1. or.hibernate.cf."on3uration

&he followin are the steps which will be used to develop Hibernate

application.

1 "reate "on3uration =bject.' "all the "on3uration- method by usin the "on3uration =bject.


12/691

) 8et #ession@actory =bject by usin "on3uration =bject! we use a

method build #ession@actory-.+ 8et #ession =bject by usin #ession@actory. "all the method

open#ession-./ 8et the &ransaction =bject.

"reate the 7=0= class =bject which we would like to perform the=perations. #tore the data in the 7=0= class =bject.F "all the methods saveBupdateBdeleteBload methods.G End &ransaction by usin commitBrollback.

1 "lose #ession =bject.

11 "lose #ession@actory =bject.

%e&uirement:

Develop a Hibernate application to insert records in to the emp table.&he followin is the java code which is used to store the data into emp

table.

public class #toreEmpDetailsR

public static void main-#trin arsVWR

"on3uration cf P new "on3uration-N

cf.con3ure-N

#ession@actory sf P cf.build#ession@actory-N#ession hsession P sf.open#ession-N

&ransaction t5 P hsession.bein&ransaction-N

Emp e P new Emp-N

e.setEno-1N

e.set*ame-,aju2N

e.setAddress-Hyd2N

hsession.save-eN

t5.commit-Nhsession.close-N

sf.close-N

S

S

Note:


13/691

4hen we ,un the same application for two times we ot an

E5ception sayin that "onstraintKiolationE5ception.

1. 4hen we create the con3uration object we are create an

environment to store the con3uration details. In this con3uration

object we can store Driver class! url! username! password andmappin information.

'. 4hen we call cf.con3ure it checks for hibernate.cf.5ml 3le in the

"?A##7A&H. If it is available it start readin the contains from

hibernate con3uration 3le. *ow the hibernate 3le the

correspondin hbm 3les it opens all the hbm 3les and try to read

the contents from all hibernate mappin 3les. All this information

stored a 0K(6s memory -con3uration object. If the con3uration

object not available in the class objects it throw E5ceptionor.hibernate.hibernateE5ception.

Note:

&his method is an E5pensive operation. In a project it is

recommended to call the con3ure method only once in the project life

cycle.

public class #toreEmpDetailsR



cf.con3ure-N

#ession@actory sf P cf.build#ession@actory-N

#ession hsession P sf.open#ession-N


Emp e P new Emp-N

7roduct p P new 7roduct-N

e.setEno-1N

e.set*ame-,aju2N

e.setAddress-Hyd2N

p.setId-1N

p.set*ame-,ice2N

p.setAmount-1N

hsession.save-eN

hsession.save-pN

t5.commit-N


14/691

hsession.close-N

sf.close-N

S

S

&his method is an e5pensive operation in a project it is recommended tocall the con3ure method only once in the project life cycle.

In any frame wrote we can chane the con3uration 3le name accordin

to our re%uirement.

If you are usin our own con3uration 3le name we have to use the over

loaded con3uration method.

Ex: cf.con3ure-myproject.5ml2N

Note:

&he default con3ure method always check for hibernate cf.5ml3le. It always recommends usin .cf in the con3uration 3le name.

$ecause of this we can easily reconiXe the con3uration 3le name.

hibernate.cf.5ml

.hbm.5ml

4hen we call cf.build #ession@actory- method it ets driver class! url!

username and password these values are supplied as input to hibernate

internal connection pool. *ow the hibernate internal connection pool. 8et

the connections from database servers.

con3uration-N


15/691

*ow the build #ession@actory method ets a connection from connection

pool and establish the connection with database server. It will check

weather all the re%uired tables are available or not. If not available if

re%uired build #ession@actory- method create the tables. It is the

responsibility of hibernate build #ession@actroy- to create all the ;"Y,D6

%ueries for every table and store the %ueries in 0K(6s memory now thebuild #ession@actory close the connection.

Note: callin build #ession@actory- method repeatedly in the project is

not recommended. It is recommended to call only once in life time of the

project.

$y default build #ession@actory- method is not cratin the tables. If you

want to hibernate to create the tables we have to supply an additionalproperty ;hbm' ddl.auto6 these properties can take any of the followin

four values create! update and createCdelete! validate.

&he followin is the ta which has to be added to Hibernate con3uration

3le.

Uproperty name P hbm'ddl.auto2MupdateUBpropertyM

It is always advisable to et a session =bject when ever we would like to

carry out any work by usin Hibernate. It6s always recommended to closethe session =bject after we 3nish the work. 8ettin a session object to

similar to ettin a connection object in 0D$".

4hen ever the session object is created immediately Hibernate starts a

cache object and it will be associated to session object are all this cache

objects as 1stlevel cache Hibernate remove the cache object when ever

we close the session object.

Arrays we have to start transaction after the session object is created.

4e need to start the transaction only for insertBupdateBdelete operation

only. 4e no need to start the transactions for retrieve the records.

4hen we call hsession save hibernate takes the object and add it to 3rst

level cache by usin a reistration code is &$#2 to be save.

eno: 1

name: abc

address:


16/691

"ache

4hen we call t5.commit2 hibernate ot 3rst level cache and check are

there any object are available in 3rst level cache it the objects are

available hibernate check. &he reistration code of the object hibernate

3nd to which 7=0= class this object is created and to which table this

7=0= class is mapped.

$ased on the table name and reistration and hibernate et the insert

%uery from the 0K(6s memory. It is the responsibility hibernates to

replace positional parameters with appropriate values from the object.

*ow the hibernate add the %uery to batch object.

*ow the hibernate send the batch object to Database server if it ot

e5ecute successfully it returns an identi3es value. If the batch is failed it

throws an e5ception batch update e5ception.

Hibernate send a s%l %uery to Database server to see the s%l %uery sent

by hibernate we can add property showCs%l2. &his attribute takes a

$oolean value.

Ex:

Uproperty name P showOs%l2MtrueUBpropertyM

&o see all the messaes are work done by hibernate we can use

lo+j.properties.

session

&$#

lo+j.root loer P DE$Y8BA1

lo+j.appender.A1 P or.A7Ache.lo+j.console

Appender


17/691

4e can use a method persist2 to store the data into database server.

'ntax: void persist-object

Ex: serialiXable save-object

4hen we enerate hbm 3les and 7=0= classes in hibernate by usin IDE

based on the column data type IDE enerate the appropriate data type in7=0= class for e5ample eno number-1/ IDE uses bi decimal data type

for eno number-' IDE uses byte and etc.

As part of java/. sun micro system as added a feature auto bo5in. &he

advantae of auto bo5in is we ?A* directly convert primitive data type

values to wrapper classes.

Ex:int a P 1N

inteer i P aN

system.out.println-iN

4hen we tryin to dual with auto bo5in for double data type as shown

below we are ettin the compilation error.

Ex: Double d P 'dN

develop a Hibernate application to retrieve a record from emp table

where eno is 'L

public class ,etrieve,ecordsR

public static void main-#trinVW arsR


cf.con3ure-N



Emp e P new Emp-N

Hsession.load-e!new $idecimal-'N

#ystem.out.println-e.etEno-N

#ystem.out.println-e.et*ame-N

#ystem.out.println-e.et#alary-N


18/691

hession.close-N

S

S

4hen we call the load- method the internal code of Hibernate has

performed the followin steps.#tep 1: It has checked the correspondin 7=0= class name for the

supplied object.

#tep ': It has checked this 7=0= class object is mapped to which table for

that table Hibernate has picked appropriate select %uery. &he followin is

the %uery available in 0K(6s memory.

#elect eno! name! salary from emp where eno PL *ow the

Hibernate has replaced the positional parameter value with ' and

send the %uery to database server. Database server has e5ecuted the select %uery and represented the

records in the result set object and iven into hibernate software.

Hibernate software has taken from ,esult#et object and by usin

the etter method ot the data from ,esult#et object and stored it

in 7=0= class object. *ow the Hibernate added the 7=0= class object to 1stlevel cache.

Note: If we try to call a load cs method on a non available recordHibernate throw an e5ception sayin

;or.hibernate.=bject*ot@oundE5ception6.

&o check weather any object is available in 1stlevel cache or not we can

use a method ;contains-6.

'btax: boolean "ontains-object

4rite a hibernate application to delete the records from product table

whose productID is 11.&o delete the records from hibernate we can use

two approaches.

pproach *: ?oad the record and mark the object as to delete.

public class Delete,ecordsR




19/691

cf.con3ure-N





hsession.load-p!11N BB step 1hsession.delete-pN BB step '

t5.commit-N BB step )

hsession.close-N

S

S

#tep 1: when step 1 is e5ecuted it has retrieve the records whose

primary key value is 11 and add into 1st

level cache.#tep ': 4hen we call the method object is marked as to be deleted.

#tep ): when we call the commit method the hibernate software ot the

delete %uery and replaces the positional parameter with primary key

value and send the %uery to database server.

In this approach 3rst we are checked in whether the record is available or

not if the record is not available. &he load- method throws object not

found e5ception.

pproach +: "reate the 7=0= class object and supply the primary key

value. (ark the 7=0= class object as to be deletin by callin the delete

method.

Ex:

public class Delete,ecords1R



cf.con3ure-N




p.setpid-11N

hsession.delete-pN

t5.commit-N


20/691

hsession.close-N

S

S

In this approach when we call the delete method object is marked as to

be deleted. 4hen we call the commit- method it has perform thefollowin ) steps.

#tep 1: It check weather primary key value is available in the supplied

object or not. If not available it will not carry out any work.

#tep ': If the primary key value is available a select %uery will be send to

database server to check weather record is available or not.

#tep ): If the record is available in D$ hibernate send the delete %uery. If

the record is not available hibernate will not do any work.

pproach *: Ypdatin a record into database server which ever the

record we would like to update load the record by callin load- method

modify the values by usin setter methods in the loaded 7=0= class

object. *ow mark the object as to be updated.

Ex:

public class Ypdate,ecordR

public static void main-#trinVW arsR"on3uration cf P new "on3uration-N

cf.con3ure-N



Emp e P new Emp-N

hsession.load-e! new $iDecimal-'N

e.set*ame-,aju2N

hsession.update-eN

t5.commit-N

hsession.close-N

S

S


21/691

pproach +: Hibernate uses a directory object techni%ue to check

weather object value is modi3ed or not. If the value is not modi3ed.

Hibernate will not send any update %uery to the database server. If the

values are modi3ed Hibernate send an update %uery to database server.

pproach ,: In this approach create 7=0= class object to the class whichwe would like to update the record and store the data into 7=0= class

object. 4e need to mark the object as to be updated.

Ex:

public class Ypdate,ecordR



cf.con3ure-N

#ession@actory sf P cf.build#ession@actory-N#ession hsession P sf.open#ession-N

Emp e P new Emp-N

e.setEno-new $iDecimal-'N

e.set*ame-ttt2N

hsession.update-eN

t5.commit-N

hsession.close-N

SS

evict(): evict- method is used to remove a speci3ed object from the 1 s

level cache.

Ex:


hsession.load-e!new $iDecimal-1N

e.set*ame-,aju2N

hsession.evict-eN

t5.commit-N

4hen we run the above application with out evict- method. It has

update a record into database server. 4hen we run the some application


22/691

with evict- method. It has removed employee object from 1st leve

cache.

merge(): mere method is used to add a speci3ed object to the 1 s

level cache.

Ex:Emp e P new Emp-N

e.setEno-new $iDecimal-''N

e.set*ame-A$" modi3ed2N

e.set#alary-1')+dN

hsession.mere-eN

t5.commit-N

4hen the mere- method is called the object is added to 1st

level cachewithout reistration code. 4hen t5.commit- method is called it will et

the object which does not contain the reistration code. It will check

weather the object is available in database server by sendin select

%uery. If the record is not available it will send an insert %uery to

database server. If the record is already available it will send a an update

%uery to database server.

&here three states are available to hibernate objects they are:

1. &ransient'. 7ersistent

). Detached

!ransient: An object is which is not associated with any session object.

Persistent: An object which is added to 1st level cache is called as

persistent state.

Detached: An object which is removed from 1st level cache is called

detached state.

$lear():

"lear is used to remove all the objects from 1 stlevel cache

&his will remove unperformed operations like save and update also. &he

clear- method will evict all available objects.


23/691

$onnection():

&his method is used to et leacy database connection.

8enerally this is not recommended approach in hibernate. 4e use this to

perform some operations which can not be done by usin hibernate.

Ex:

#ession hsession P sf.open#ession-N&ransaction t5 P hsession.bein&ransaction-N

"onnection con P hsession."onnection-N

#tatement stmt P con.create#tatement-N

stmt.e5ecuteYpdate-Insert into emp values-'!6sadaf6!')+2N

t5.commit-N

In Hibernate when we et the connection object by default auto commit

mode to false.4e have multiple over loaded methods as for session interface they are:

void load-object! pid

object load-class! serialiXable

Ex:

"lass c P class.for*ame-info.inetsolv.product2N

=bject o P hsession.load-c!lN

7roduct p P -productoN

#ystem.out.println-p.et7id-N#ystem.out.println-p.et*ame-N

#ystem.out.println-p.et7rice-N

4hen we call the above load- method if the record is available load-

method creates 7=0= class object and store the data and return 7=0=

class object if the record is not available load- method will not create

7=0= class object.

4e have a static variable class as part of object class when ever we call

that variable by usin class name it returns the callin class classobject.

Ex:

"one.class

4hen the above code is e5ecuted it has return class object.

name P

"one

packae Pnull


24/691

"lass

get():

et- method is also used to retrieve the record from database server if

the record is available it returns that 7=0= class object. If record is not

available it returns null value.

Ex:

=bject o P hsession.et-product.class!'N

If-oZ P nullR

7roduct p P -productoN#ystem.out.println-p.et7id-N

#ystem.out.println-p.et*ame-N

#ystem.out.println-p.et7rice-N

S

elseR

#ystem.out.println-,ecord is not available2N

S

-ush():

4hen we call in [ush- method all the objects which are

available in 1st level cache will be converted into %ueries and send to

database server. @lush will not store data permanently. 4hen we all the

commit- method the data is stored permanently.

Hbmadd?.auto property takes by diJerent values

1. Ypdate'. "reate). "reateCdrop+. Kalidate


25/691

If hbmaddl.auto P update and weather the build#essionfctory- method

is e5ecuted it checks weather tables are available or not. If not available

it create the takes.

If hbmaddl.auto P create if the tables are not available

build#ession@actory- method creates it. If the takes and create aain if

hbmaddl.auto P createCdrop if the tables are not available it creates thetables. when we close the session factory object the tables will be

dropped.

If hbmaddl.auto P validate! build#ession@actory- method check weather

the tables are present in the database server or not. If not available it will

throw an error messae missin table.

Developing Hibernate application b using manual procedure:

&he followin is an architecture of hibernate application.

#tep 1: "reate a table in the data base server.

#tep ': 8et the Hibernate software and placed in a lib folder -copy

ojdbc1+.jar also.

Note:

4e can et the jar 3les from IDE.

#tep ): Develop a cmd 3le which contains the class path to all the

Hibernate related jar 3les.

Ex: #et "?A##7A&HPlib\antlr.'...jarNlib\")7C.G.1.jarN

#tep +: "reate the 7=0= class. 4e can use any class name as 7=0= class

name for e5ample.

0ava application

Hibernate #B4

Hibernate.properties

or

Hibernate.cf.5ml

Database #erver


26/691

public class EmployeeR

int emp*oN

#trin emp*ameN

double emp#alaryN

public void setEmployee*o-int employee*oR

this.emp*o P employee*oN S

public int etEmployee*o-R

return empnoN

S

"reate hbm 3le the name of hbm 3le can be any thin.

UL5ml version P 1.2LM

UZ D="&7E hibernate.mappin public somethin2 http:BBwww.hibernate.orBdtdBhibernateCmappinC).dtt 2M

UhibernateCmappinM

Uclass name P info.inetsolv.Employee2table P emp2M

Uid name P employee*o2M

Ucolumn name P eno2BM


UBidM

Uproperty name P employee*ame2MUcolumn name P name2BM

UBpropertyM

QQQQQQQQQQ.

UBclassM

UBhibernateCmappinM

Develop hibernate con3uration 3le.

UL 5ml version P 1.2LM

UZ D="&7E hibernateCcon3uration public hibernateCcon3uration2!

2http:BBwww.hibernate.orBdtdBhibernateCcon3urationC

)..dtt2M

UhibernateCcon3urationM

Usession factoryM

QQQQQQQQQQQ.

UBsession factoryM
http://www.hibernate.org/dtd/hibernate-mapping-3.0dtthttp://www.hibernate.org/dtd/hibernate-configuration-3.0.dtthttp://www.hibernate.org/dtd/hibernate-configuration-3.0.dtthttp://www.hibernate.org/dtd/hibernate-mapping-3.0dtthttp://www.hibernate.org/dtd/hibernate-configuration-3.0.dtthttp://www.hibernate.org/dtd/hibernate-configuration-3.0.dtt


27/691

UBhibernateCcon3urationM

Develop a java application to store the data into database server.

&he parser proram check for hibernate dtd 3le as part of hibernate 3le.

As part of hbm 3le we can remove the column ta or attribute if the 7=0=

class properties and column names are same.

&he followin is sample con3uration for emp table.

UhibernateCmappinM

Uclass name P info.inetsolv.Employee2M

Uid name P employee*o2BM

Uproperty name P employee*ame2BM

Uproperty name P employee#alary2BM

UBclassMUBhibernateCmappinM

4e can club multiple hbm 3les into a simple hbm 3le. $ut this approach

is not recommended for bi projects! it is recommended to use one hbm

3le $r=ne one 7=0= class.

UhibernateCmappinM

Uclass name P info.inetsolv.Employee2MUclass name P info.inetsolv.7roduct2M

Uid name P 7id2 access P 3eld2BM

Uproperty name P name2 class P 3eld2BM

UBclassM

UBhibernateCmappinM

4e can develop hibernate application with out hibernate con3uration

3le. $ut we have to provide the properties and mappin 3les throuh the

java proram.

Ex:

public class #toreR



cf.set7roperty-hibernate.connection.driverOclass2!2oracle.jdbc.driver.=r

acleDriver2N


28/691

cf.set7roperty-hibernate.connection.url2!2jdbc:oracle:thin:Tlocalhost:1

/'1:5e:2N

cf.set7roperty-hibernate.connection.username2!2hib2N

cf.set7roperty-hibernate.connection.password2!2abc2N

cf.set7roperty-hibernate.dialect2!2or.hibernate.dialect.=racleGDialect

2Ncf.set7roperty-hibernate.showOs%l2!2true2N

cf.add,esource-a.hbm.5ml2N

session@actory sf P cf.build#ession@actory-N

session hession P sf.open#ession-N

QQQQ

QQ..

Q.

SS

Instead of add,esource- method we can use add"lass- method.

Ex:

cf.add"lass-info.inetsolv.product.classN

when we use add"lass- it will check for info.inetsolv.product.hbm.5ml

3le.&he disadvantae of prorammatic con3uration is when Hard codin

the values in the java proram. If we want to communication with same

hibernate application with diJerent database server. 4e have to chane

the java code because of this reason this approach is not recommended.

8enerally in the projects we use properties 3les to remove hard codin.

(ost of the projects uses property 3le end with an e5tension dot -.

properties inside the properties 3le we supply a data in the form of key

and value.

Ex:

9ey P value BBmyproject.properties

4e can con3uration hibernate parameters as part of a propertyC3le.

4ho6s name is hibernate properties.

Ex:

hibernate.connection.driverOclass P oracle.jdbc.driver.=racleDriver


29/691

hibernate.connection.url P jdbc:oracle:thin:Tlocalhost:1/'1:5e

hibernate.connection.username P hib

hibernate.connection.password P abc

hibernate.dialect P or.hibernate.dialect.=racleGDialect

hibernate.showOs%l P true

BBsave hibernate.properties

It6s not recommended to use property 3le as part of hibernate. &his is

because as part of the property 3le are can6t con3uration the mappin

resource 3les.

4e can supply the values by the properties usin system properties

when we run the application.

Ex: CDhibernate.connection.driverOclass P oracle.jdbc.driver.=racleDriver

(eaerly hibernate is divided into three parts. &hey are:

Hibernate #B4

Hibernate #B4 is ood at =,( as well as transaction manaement the

internal hibernate code uses two connections pools ")7! D$"7. It6s not

recommended to use there connection pools. It6s always recommended

to use the e5ternal connection pool like weblogicconnection pool.

Ysin procedure to use webloic connection pool proram in hibernate.

1. "on3ure webloic server connection pool by specify 0*DI name.'. 8et the hibernate #B4 place in lib folder and set the class path.). "reate 7=0= class and hbm 3le.+. "reate hibernate con3uration 3le with data source! username and

password and jndi.class and jndi.urlUhibernateCcon3urationMU#essionC@actoryM

"onnection (anaement

=,(

&ransaction (anaement


30/691

Uproperty

namePhibernate.connection.datasource2MmypoolUBpropertyMUpropery

namePhibernate.connection.username2MadminUBpropertyMUpropery

namePhibernate.connection.password2MinetsolvUBpropertyMUpropery

namePhibernate.jndi.class2Mwebloic.jndi.4?Initial"onte5t@actory UBpropertyMUpropery

namePhibernate.jndi.url2Mt):BBlocalhost1BUBpropertyMUpropery namePhibernate.showOs%l2MtrueUBpropertyMUmappin resource P a.hbm.5ml2BMUB#essionC@actoryM

UBhibernateCcon3urationM/. Develop the hibernate application to store the data into database

server.Note: we have set the class path to web.jar or set DomainEnv.cmd

. 4hen we are con3uration are usin connection pool as part of

hibernate we have choose use jndi data source rather then jdbc

driver.. &o set the class path to resolve the problem of

webloic.jndi.4?Initial"onte5t@actory we are added webloic.jar in

the class path.F. Hibernate can be used to communicate with any D$ server.

Procedure to develop hibernate application to interact with

./'01:

4hen we communicate with (#>? D$ #erver. 4e have chane the url!

username! driver class and etc.

4e have to always use wrapper classes2 as part of 7=0= classes instead

of primitive data types. 7rimitive data types occupy less amount ofmemory when compared with wrapper classes. 7rimitive data types can6t

hold a null value.

Ex: public class (yAppR


int a P nullN

#ystem.out.println-aN


31/691

S

S

4hen we compile the above proram the compiler reports error messae

sayin null value can not be assined to primitive data types. we can

assined a null value to wrapper classes.

Ex: public class (yAppR


Inteer a P nullN

#ystem.out.println-aN

S

S

As part of the IDE when we eneratin hbm 3les and 7=0= classes wehave an option. 4e have primitive data types or wrapper classes. &hey

are java types and hibernate types.

4hen we choose java types it uses wrapper classes. 4hen we choose

hibernate types it uses primitive data types.

4e are try to use primitive data types and tryin to store data into

tables. In these scenarios the default values of primitive data types are

ettin store into data base server.

Ex:7roduct p P new 7roduct-N

p.set7id-7idN

p.set*ame-7nameN

hsession.save-pN

4hen we e5ecute the above code even thouh when the user is not

supplied price value application has stored . values.

4hen we use primitive data types to retrieve records from a table which

contains null values. then the application throwin an e5ception

org3hibernate3propertccessExcepton2.

$y usin 0D$" also we can represent the records in the form of objects.

&he followin is an e5ample of representin data in the form of object by

usin 0D$"L

Ex:


32/691

,esult#et rs P stmt.e5ecute>uery-select from product2N

Array?ist list P new Array?ist-N

4hile-rs.ne5t-R


p.set7id-rs.etInt-1N

p.set7id-rs.et#trin-'Np.set7id-rs.etDouble-)N

list.add-pN

S

#ystem.out.println-After: ? A7I'. "riteria A7I). *ative s%l A7I

4hen we develop jdbc application to communicate with any database

server to remove the hard codin we use property 3les. As part of the

property 3les we have provided driver class! url! username! password

and %ueries. If we would like to communicate with other database

servers we chane the values from property 3les.

7roperty 3les

0D$" Application

Driver classurl

username!

password

D$ #erver


33/691

H>? %ueries as iven as input to hibernate #B4 it is the responsibility of

hibernate to convert H>? %uery into correspondin #>? %ueries and send

into data base server.

Hibernate uys has provided so many direct classes. As part of this

dialect classes the code is provided to convert H>? %uery to

correspondin s%l %ueries.

&he dialect classes are available in org3hibernate3dialectpackae. &he

followin are some of the dialect classes. =racle dialect! (y#%l dialect!

#A7 dialect etc.

&he followin are the features of s%l.1. H>? >ueries fully object oriented.'. H>? >ueries supports inheritance and poly morphism.). H>? >ueries are case sensitive.

If we want to write H>? %ueries instead of table names we have to use

7=0= calss names.

Instead of column names we have to use property names H>? %ueries

derived from s%l %ueries. &he followin is H>? %ueries derived from s%l

%ueries. &he followin is H>? and s%l %ueries to retrieve all the recordsfrom emp table.

#>?M select from empN

&able name

H>?M from info.inetsolv.Employee

7=0= calss name

0ava proram usin H>?

Hibernate #B4

=racle (y#%le D$'


34/691

Develop a hibernate application which uses H>? %ueries to retrieve all

the records from emp table.

Procedure to use H01 in herbernate:

1. ,epresent H>? %uery in the form of %uery object.

'. #end the %uery object to hibernate software by callin the listmethod.

). Hibernate #B4 returns an Array?ist object render the Array?ist

object and display the output to client.+. >uery is an interface which is available as port of or.hibernate

packae. 4e can not create the object to %uery interface. 4e can

create a reference variable and it holds implementation class

object.

public class ,etrieveDataR


BB #tandard code


>uery %uery P hsession.create>uery-h%l %ueryN

?ist l P %uery.list-N

Array?ist emplist P -Array?istlN

Iterator i P emplist.iterator-N

while-i.has*e5t-REmployee e P -EmployeeN.ne5t-N

#ystem.out.println-e.etEmployee*o-N

#ystem.out.println-e.etEmployee*ame-N

#ystem.out.println-e.etEmployeeAddress-N

S

hsession.close-N

S

S

4hen we call the listmethod the followin steps are carried out by list-

method.

1. H>? %uery will be converted into correspondin #>? >uery.'. Hibernate #B4 send #>? %uery to database server.


35/691

). &he database server e5ecutes select %uery and return the ,esult#et

object to hibernate #B4.+. Hibernate #B4 represents every record in the form of object and add

it to array list object./. ?ist- method converts Array?ist into supper class reference variable

list and it returns it we have to et Array?ist object and displayrecords to client.

4hen we tryin to add any element to Array?ist object it will be

converted into supper class object called as object. 4hile retrievin data

from Array?ist we need to typecast into appropriate object.

As part H>? %ueries we can add where conditions as well as order by

clause! roup by clause.

using where clause as part o H01:

#>?M select from emp where enoM'N

H>?M from info.inetsolv.Employee where employeeM'N

using positional parameters in H01:

&he followin is an e5ample of usin positional parameters in H>?.

#>?M select from product where price ML And priceUL

H>?M from product where priceML And priceML

Ex:

#trin %uery P from product where priceML And priceUL2N

>uery h%l%uery P hsession.create%uery-%ueryN

h%l%uery.#etDouble-!'N

h%l%uery.#etDouble-1!/N

Array?ist ?ist P -Array?isth%l%uery.list-N

In hibernate the H>? %uery positional parameter inde5 starts with .

If we do not supply the values to all positional parameters hibernate

display an e5ception %uery e5ception.4e can use alias names as part of H>? %uery by usin a keyword as.

Ex:

#trin %uery P from product as p where p.priceML and p.priceUL2N

4e can use order by as part of H>? %ueries.

Ex:


36/691

from product order by price desc

%etrieving specifc columns rom emploee table:

&he followin e5ample et employee*o! employee*ame columns only

from the database server.

#trin %uery P select employee*=!employee*ame frominfo.inetsolv.Employee2N

>uery h%l %uery P hsession."reate>uery->ueryN

Arraylist ?ist P -Arraylisth%l>uery.?ist-N

Iterator i P list.iterator-N

4hile-i.has*e5t-R

=bject oVW P -objectVWN

*e5t-N

BBcode to display the data from arrays usin inde5.for-int jPoNjU.lenthNjuery %ue P hsession."reate>uery-%N

1

' etwo

Inteer

Inteer

1

eone

etwo

'

A

,

,

A

?

I

#

&


37/691

Array?ist list P -Arraylist>uery.?ist-N


while-i.has*e5t-R

=bject o P i.ne5t-N

Inteer ii P -InteeroN

#ystem.out.println-iiNS4hen we have only one column in the select clause as part of the array

list the data type will be added.

#trin

#trin

#trin

#trin

rs

4e can use areate functions in H>? %ueries. &he followin is an

e5ample usin H>? to 3nd number of records available in product table.

#trin % P select count- from product as p2N

>uery %ue P hsession."reate>uery-%N

Array?ist list P -Array?ist%ue.?ist-N


while-i.has*e5t-R

=bject o P i.ne5t-N

?on l P -?onoN

#ystem.out.println-oN

S

eone

etwo

ethree

efour

eone

etwo

ethree

efour

A

,

,

A

?

I

#

&


38/691

4e can join multiple tables and retrieve the records the followin is an

e5ample of join tables.

>uery H>?%uery

Array list P -ArraylistH>?%uery.?ist-N

Iterator :P list.iterator-N

while-i.has*e5t-R=bject oVW P -objectVWi.ne5t-N

for-int jPNjU.lenthNjuery h%l>uery P hsession.create>uery->ueryN

h%l>uery.set#trin-!25yX2N

h%l>uery.setInteer-1!1N

int no P h%l>uery.e5ecuteupdate-N

#ystem.out.println-noN

t5.commit-N

hsession.close-N

S

S

Note:

4hen we perform update! delete and insert operations. 4e must

place the code in a transaction.


39/691

H%l will not support to insert record directly into table. if the data is

already available in table we can copy from one table to another table.


#trin >uery P insert into

Employee-employee*o!employee*ame select pid! name

from product2N>uery h%l >uery P hsession.create>uery->ueryN

int no P h%l >uery.e5ecuteupdate-N

#ystem.out.println-noN

t5.commit-N

hsession.close-N

S

Named positional parameters:4hen we write the h%l >ueries we can use positional

parameters the problem with positional parameters is if somebody tryin

to read and understand it takes lot of time. Instead of positiona

parameters we use names. &his will improve the readability of the

%ueries.

*amed positional parameters will not improve performance separately.

&his is because by default named positional parameters also uses

prepare statements. &he followin is an e5ample of named positionalparameter.

Ex:

@rom product where priceM:min value and priceU:ma5 value. &he

followin is an e5ample of usin named positional parameters.

#trin >uery P from product where priceM:minvalue and

priceU:ma5value2N

>uery h%l >uery P hsession."reate>uery->ueryN

h%l >uery.setDouble-minvalue2!'N

h%l >uery.setDouble-ma5value2!N

Arraylist list P -Arraylisth%l>uery.?ist-N

In hibernate to retrieve the data from all the tables we can use h%l %uery

like from java.lan.object

Ex:


40/69


41/691

Hibernate uys has iven prede3ned classes to add the restrictions. &hey

are available as part of or.hibernate.criteria packae some of the

important classes in that are restrictions!order! property etc.

&he followin is code to add restrictions to criteria.

"riteria c P hsession.create "riteria-7roduct.classN

c.add-,estrictions.e-price2!'dNc.add-,estrictions.le-price2!+dN

&he ,estrictions class contains couple of static factory methods. &he

internal code of these methods add- the where conditions to the >uery

as a developer we are responsible to use these methods based on the

re%uirements.

&o sort the records based on "riteria A7I they have provided prede3nedclasses like order. &his contains the methods like asc! desc.

Ex:

"riteria c P hsession."reate "riteria-product.classN

c.add=rder-order.desc-price2N

&o retrieve the speci3c columns from the data base table we use

projections class.

Ex: "riteria c P hsession."reate "riteria-product.classN

c.set7rojection-7rojections.property-name2N

4hen we run the above java proram the Array list object contains the

columns correspondin data type.

adding multiple projections:

"riteria c P hsession."reate "riteria-7roduct.classN

7rojection?ist pl P projections.7rojection?ist-N

7l.add-7rojections.property-name2N

7l.add-7rojections.property-pid2N

c.set7rojection-plN

Note:


42/691

"riteria A7I is not best sui table for the real time projects and to

develop complicate >ueries for e5ample usin the functions like di code!

nul1! nul' etc.

Native '01 PI:

&he main advantae of *ative #>? is we can write data basespeci3c >ueries as part of hibernate. $y usin *ative #>? A7I we can

perform the operations like insert >uery! update! delete! retrieve and call

the procedures and etc.

&he followin is an e5ample of callin the procedure by usin *ative #>?.

Ex:


#>? >uery >uery P hsession.crete#>?>uery-Rcall myprocS2N

>uery.e5ecuteYpadate-Nt5.commit-N

How do we use hibernate in web based applications4

How do we use hibernate in sturts4

1. "reate a web based application.'. "opy all the hibernate related jar 3les into project lib folder.). "opy hibernate con3uration 3le! 7=0= classes! hbm 3les and

hibernate con3uration 3les into classes folder.

+. "reate hbm 3le and servlet to capture data and store data.

5enerators:

In all the applications which we developed as of new end user is suppose

to enter the primary key values.

It is not recommended to ask the end user to enter to enter the primary

key values. It6s always recommended to enerate primary key values by

the application. &his resolves the problem of end user rememberin the

primary keys.$y usin 0D$" we have to write code to enerate primary key values. If

we use hibernate internally it contains a loic to enerate the primary

key values.

pproach*:


43/691

In this approach we 3nd the ma5imum values from correspondin table

and increment by one and use it as primary key value to 3nd the ne5t

primary key value we can use the followin %uery.

Ex:

#elect ma5-eno < 1 from empN

&his loic can be used in any data base server.

pproach+:

=racle data base server supports a feature se%uences to enerate the

primary key values to create the se%uence we use the followin %uery.

Ex:

create se%uence empse%

min value 1

ma5 value GGGGGincrement by 1

start with 1N

&o see all the available se%uences in the data base server. 4e use the

followin %uery.

#>?M select from userOse%uencesN

pproach,:In mys%l there is a feature auto increment. If we use it mys%l itself will

increment the primary key values.

&o use auto increment at the time of table is created we must specify

auto increament.

Ex:

create table product-pid int-/ primary key autoOincreament!

name varchar-'!

price decimal-1N

&o insert the values we use the followin %uery.

Ex: insert into product-name!price values-;abc6!++/N

auto increment will write in mys%l and D$'. It does not work in oracle.

Hibernate has iven set of prede3ned classes to deal with primary key

values. &hese classes are available in a packae. or.hibernate.id2


44/691

&he followin are some of the classes of hibernate enerators.

1. Assined'. #e%uence enerator). Increment enerator+. uuid enerator/. uid enerator etc.

Hibernate uys has iven an interface identi3er enerator this contain a

method enerator.

All the above enerator classes must provide implementation to an

interface identi3er enerator. As part of the enerate method the loic isprovided to enerate the primary key value. &his method returns primary

key value in the form of serialiXable object.

As part of the hbm 3le there is a ta enerator. &his specify the

enerator which has to be used by hibernate.

E6:

Uenerator class P or.hibernate.id .#e%uence 8enerator2BM

Hibernate uys has provided short names for every enerator. 4e can

use the short names on be half of class names. &he followin are some ofthe short names. Assined! se%uence! increment! native! hilo! uuid etc.

&he followin is an e5ample of usin short names.

Uenerator class P se%uence2BM

$efore we use a enerator we have to check the followin two steps.

1. 4eather this enerator can be used in the correspondin data base

server or not.

'. 4e need to check weather the enerator supports speci3c datatype or not.

ssigned generator:

4hen we use assined enerator hibernate e5pect us to supply primary

key value by default when we enerator hbm and 7=0= classes enerator

is assined with assined value.

Identi3er enerator

#erialiXable enerate-QQQ


45/691

In the hbm 3le we can use enerator with hibernate class name or short

name.

Uid name P pid2 type P inteer2M

Ucolumn name P pid2BM

Uenerator class P or.hibernate.id.Assined2BMUBidM BB product.hbm.5ml

=,

Uid name P pid2BM

Ucolumn name P pid2BM


UBidM

In the hbm 3le if we does not supply the enerator ta by default

hibernate consider assined enerator.

If we supply a wron class name or invalid enerator class name

hibernate throw an e5ception could not instantiate id enerator.

Increment generator:

4hen we use this enerator it will increment the primary key valueby one based on e5istin primary key value. &his alorithm internally

uses the e5istin primary key value.

4hen we use this alorithm it will use the followin %uery to 3nd the

ma5imum primary key value.

Ex: select ma5-pid from product

&he followin is the con3uration of increment enerator.

Uenerator class P or.hibernate.id.Increment 8enerator2M

UBeneratorM

Uenerator class P Increment2M

UBeneratorM

Increment enerator can enerate the primary key values for short! lon!

inteer data types only.

4e can use increment enerator in mys%l data base server also.


46/691

Identi generator:

&his enerator can be used only in mys%l data base server to use

this enerator compulsory the table must be auto increment. &he

followin is the con3uration of identify enerator.

Uenerator class P or.hibernate.id.dentity enerator2BM

=,Uenerator class P identity2BM

(se&uencehilo):

'e& hilo: &his enerator uses both se%uence as well as hilo value to

enerator a primary key value. &his is same as hilo enerator. this uses

the se%uence instead of table. the followin is the con3uration for

se%uence hilo enerator.

Uenerator class P se%hilo2MUparam name P se%uence2Mpidse%UBparamM

Uparam name P marOlo2M/UBparamM

UBeneratorM

7uid8guid: &hese enerators enerate the primary key value based on

the I7 address of the system and the start up time of 0K( and convert it

into )' bit he5adecimal number and store in data base server.

&o work with uidBuuid enerators the primary key value data type mustbe var char with minimum siXe of )' bit. &he followin is the

con3uration of enerator.

Uenerator class P uuid2BM

Instead of prede3ned enerator we can use our own enerator also to

et the primary key values.

&o develop our own enerator class it must provide implementation to

interface identi3er enerator. In this we need to provide the

implementation to enerator method.

Ex:

public class =ur=wn8enerator implements Identi3er 8eneratorR

public serialiXable enerator-#essionImplementor session! object

objectR

int eno P N


47/691

,esult#et rs P

session.etbatcher-.7repare$atch#tatement-select ma5-eno

from emp2.e5ecute>uery-N

if-rs.ne5t-R

eno P rs.etInt-1N

eno P eno < 1NS

return enoN

S

S

&o use this enerator in hibernate we have to con3ure it in hbm 3le as

show below.

Ex: Uenerator class P info.inetsolv.ourown 8enerator2BM

4hen we use hibernate in form based applications we have provided thecon3ure method and build session factory method as part of service

method.

'ingle ton design pattern:

&he main purpose of sinle ton desin pattern is it make sure that

any work e5ecute only once or it make sure that the object is created to

a class only once.

&he followin "one class makes sure that it creates only one object formultiple people.

public class "oneR

private static "one cN

#taticR

#ystem.out.println-creatin "one object only once2N

c P new "one-N

S

public static "one create "one object-R

return cN

S

7rivate "one-R

#ystem.out.println-"one object is created2N

S

S


48/691

&o et the "one class object we use a method created "one object

public class (yApp-R


"one c1 P "one.create "one object-N"one c' P "one.create "one object-N

#ystem.out.println-c1N

#ystem.out.println-c'N

S

S

&he followin is hibernate sinle ton desin pattern. &his class make sure

that session factory is created only once.

public class Hibernate #ession@actory#inle&onRprivate #tatic #ession@actory sf P nullN

#taticR


cf.con3ure-N

sf P cf.build#ession@actory-N

S

public #tatic #ession @actory et#ession@actory-R

return sNS

private Hibernate#ession@actory#inle&on-R

S

S

As part of a servelet we et the session object directly from sinle ton

desin pattern.

Ex: public class #tore7roduct#ervlet e5tends Http#ervletR

public void service-. . . . . . R

#ession hsession P Hibernate#ession factory sinle ton .

et#ession-N

. . . . . . . .

. . . . . .

. . . .


49/691

hsession.close-N

S

S

&he followin is an e5ample hibernate temple desin pattern. $y usin

this any body can perform the some operation by usin one line.

Ex:public static void save-object oR

#ession hsession P Hibernate session factory.et#ession-N

hsession.bein&ransaction-N

hsession.#ave-oN

hsession.et&ransaction-.commit-N

Hibernate session factory.close #ession-N

S

SDevelop a servlet to et a all the records from product table and display

to the client.

Named 0ueries:

*amed >ueries will improve the performance of java application.

4hen we develop a web based application to retrieve the records from

product table and display to the client by usin H>? >ueries every time it

try to convert H>? >uery into correspondin #>l >uery. 4e can improve

the performance of by usin named >ueries.

Procedure to use Named 0ueries:

1. "on3ure *amed >ueries as part of hbm 3les.Ex: UhibernateOmappinM

UclassCCC MCCCCCCCCC MUBclassMU%uery name P pd2Mfrom

info.inetsolv.productUB%ueryMUBhibernateOmappinM BBproduct.hbm.5ml'. @rom the java application to use the *amed >ueries use a

method.et*amed>uery->uery %uery P hsession.et*amed>uery-pd2NArray?ist al P -Array?ist%uery.list-NIterator i P list.iterator-N


50/691

4hen we are usin *amed >ueries we can supply named positional

parameters also.

Ex: U%uery name P pd2Mfrom info.inetsolv.product where name P:

nameUB%ueryM

*amed native #>? we can con3ure native #>? also as part of hbm 3les.&o con3ure native s%l we use a ta Us%lO%ueryM

Ex:

UhibernateOmappinM

UclassCCCCCC M

CCCCCCCCCC

UBclassM

Us%lO%ueryMname P hs%l2M select from product UBs%lO%ueryM

UBhibernateOmappinM

&o call named s%l from java application we use a et*amed >uery this

returns %uery object. 4hen this send to data base server we etArray?ist

object with objectArray as the values.

Ex: >uery %uery P hsession.et*amed>uery-hs%l2N

Array?ist al P -Array?ist%uery.list-N

Iterator i P al.iterator-N

while-i.has*e5t-Robject oVW P -objectVWi.ne5t-N

for-int jPNjUP.lenthNj


51/691

public class 0D$"4ork implements worksR

public void e5ecute-connection conR

"allable#tatemet cstmt P con.7repare"all-Rcall myprocS2N

cstmt.E5ecute-N

S

S4hen we write the business loic in the procedure they will improve the

performance. &he disadvantae of this approach. If we chane the data

base server the application will not work as a java prorams we

recommend to write the business loic in java application.

Hibernate is not the best solution when we write the business loic

in procedure. It6s not recommended to use procedures in the projects

which uses hibernate. 4e are seen three approaches of callinprocedures from hibernate.

1. $y ettin the connection from session object.'. $y usin native #>? application.). $y usin do work method.

4hen we use do work method hibernate internally uses callback

mechanism to call e5ecute method the advantae of this is we are not

openin the connection we are not closin the connection. A procedure

can write multiple records to achieve this we have to use cursors in

procedure.

"ursors are a temporary memory area. 4here the records will be stored

the cursor object will be created by oracle. 4hen ever select %uery is

e5ecuted in oracle they are two types of cursors available. &hey are:

1. Implicit cursors'. E5plicit cursors

&he followin procedure returns a cursorB,esult#et object create or

replace procedure (y7roc- rs out sysOrefcursor

As

$ein

open rs for select from productN

end myprocN


52/691

B

@ollowin java application to call the procedure and display to the client.

public class 8et,ecordsR


BBstandard jdbc code

"allable#tatement cstmt P con.7repare"all-Rcall myproc-LS2Ncstmt.E5ecute-N

,esult#et rs P -,esult#et cstmt.et=bject-1N

BBcode to display the records

S

S

Hibernate uys are ivin a way to call procedure which takes a

parameter refcursor.

"on3ure procedure in hbm 3le as shown below.UhibernateOmappinM

Uclass CCCCC M

CCCCCCCCCC

UBclassM

Us%lO%uery name P cp2 callable P true2M

Ureturn class P info.inetsolv.product2MUBreturnM

Rcall myproc-LS

UBs%lO%ueryMUBhibernateOmappinM

&o call the procedure from java we use named %ueries as shown below.

>uery %uery P hession.et*amed>uery-cp2N

Arraylist al P -Arraylist%uery.list-N

Iterator i P al .iterator-N

while-i.has*e5t-R

product p P -producti.ne5t-N

S

S

4e have to follow limitations in hibernate to call the procedure.

1. &he 3rst parameter procedure must be out parameter and the data

type must be ref cursor.'. 4hen we are con3urin the procedure in we must use on attribute

callable st.


53/691

4hen we specify callable true hibernate reister. &he 3rst parameter as

out parameter we must use native s%l to call the procedure from

hibernate application.

If you want to search the records based on iven product id you have to

supply a product id as parameter to procedure. 4e can call that thecon3ure in hbm 3le as shown below.

4e can develop a hibernate software to

communicate with multiple data base servers from a sinle project

7rocedure to use hibernate with multiple data base servers for the same

project. "reate multiple hibernate con3uration 3les.

Ex:

hibernate.cf.5mlhibernate.mys%l.cf.5ml

&o use multiple data base servers in the project we use multiple

con3uration 3les and multiple session factory objects. In the projects we

do this work only once by usin a sinle ton desin pattern only.

public class Hibernate#ession@actoryR

private static #ession@actory osf P nullN

private static #ession@actory msf P nullNstaticR

"on3uration ocf P new "on3uration-N

ocf."on3ure-N

"on3uration mcf P new "on3uration-N

mcf."on3ure-hibernate.mys%l.cf.5ml2N

ocf.build#ession@actory-N

mcf.build#ession@actory-N

S

public static #ession@actory et mys%lsession@actoryR

return ocfN S

public static #ession@actory et mys%lsession@actoryR

return mcfN S

private Hibernate#ession@actory-RS


54/691

In the java application we et the re%uired #ession @actory object and

perform the operations.

Ex: #un (icro #ystem has released 07A A7I to interact with data base

servers they are released this A7I as part of 0EE standard A7I.

&he followin is the classes and interfaces as part of 07A.

$lasses Interaces 7ersistence

Hibernate uys provided the implementation to 07A A7I.

"reate a java project and add 07A capabilities. &here are so many people

who are providin the implementation same of them or top link!

hibernate and open 07A and etc. we can use any jar 3les to develop 07A

application. 4hen we add 07A capabilities it has created an 5ml 3le

whose name is persistence.5ml in this we have speci3ed persistence unitname.

8enerate an Entity $eans -7=0= classes. Develop a java

application to store the data into employee table.

public class #toreEmpR


Entity(anaer@actory emf P

7ersistence."reateEntity(anaer@actory-07A=,A"?E72NEntity(anaer em P emf."reateEntity(anaer-N

Entity&ransaction t5 P em.et&ransaction-N

t5.bein-N

Emp e P new Emp-N

e.setEno-1N

e.setEno-'N

e.setEno-)N

em.7ersist-eN

t5.commit-N

em.close-N

S

S


55/691

&he top link provides the implementation of 07A A7I to work with top link

we are to download the top link jar 3les and set the class path. 4hen we

are developin a project at the desin phase we try to develop two types

of desin.

1. Data base desin

'. 0ava desin

As part of data base desin we will decide the names of the tables and

columns of the tables and etc. At the time of developin the project

developer will not create any tables. In most of the projects we have to

capture multiple address to an employee.

Eno

*ame

Address:

#treet city state

ADD another address

&o implement above re%uirement we ot the followin desin.

Design *:

As part of desin we are addin two tables. Emp table and address table

in the Emp table Eno is a primary key. In the address table Eno! Address

no are formin the primary key.

Design +:

1

Am pet

*aidu

HD

HD

#,

A7

A7

#tore

Eno *ame #treet #tate

"ity

Eno-79 *ame

salary

Eno Addno #treet #tate

"ity


56/691

In the desin' the address table contain Eno! addressno as primary keys.

If more than one column in valued in formin a primary key we call it ascomposite primary key. Hibernate will not ive the best performance if

the table contains composite primary key. Hibernate ive the best

performance if it6s havin only one primary key.

Design ,: In this desin we have two tables. &hey are emp and address.

In the address table we will try to have a new column which acts as

primary key.

8enerally by usin hibernate we should be able to create the tables. but

accordin to the project desin 3rst we are creatin tables from the

tables we are creatin 7=0= classes. "reatin the 7=0= classes from the

table is called as hibernate reverse enineerin.

&here are some situations where we need to develop hibernate

applications based on leacy data base servers.

4hat are leacy data base serversL

&he data base server which uses composite primary key6s is called as

leacy data base servers. 7rocedure to develop hibernate applications

based on leacy data base. "reate the followin the two tables.

!able *: create table emp-eno number-/ primary key!

*ame varchar'-'! salary number-1!'N

Eno-79 *amesalary

1 *aidu

Aid Eno-79 addno #treet #tate

"ity

1 1 1 A7et HD

A7


57/691

!able +: create table address-eno number-/! addrno number-/!

#tate varchar'-'! primary key-eno! addrnoN

4hen we enerate hbm 3les and 7=0= classes we have observed that )7=0= classes and two hbm 3les the 7=0= classes are:

Emp.java

AddressId.java

Address.java

4e have not observed any chane in emp 7=0= class. &his is because

this table is havin only one primary key. 4e have observed that address

table is created. &wo 7=0= classes:

1. "omposite primary key class-AddressId'. ,eular 7=0= classes

&he composite primary key class contain two properties this is because

two columns involvin in formin composite primary key.

public class AddressIdR

Inteer EnoN

Inteer addrnoN

BBsetters and etters

S

&he followin is address.java which uses composite primary key class asa property.

public class AddressR

AddressId idN

#trin streetN


58/691

#trin cityN

#trin stateN

BBprovide setters and etters S

4e are enerated two hbm 3les. &hey are:

1. Emp.hbm.5ml'. Address.hbm.5ml

4e have not observed any chanes in Emp.hbm.5ml 3les. 4e have

observed lot of chanes in address.hbm.5ml 3le with respect to

composite primary key.

UhibernateOmappinM

Uclass name P info.inetsolv.Address2 table P Address2M

UcompositeCid name P id2 class P info.inetsolv.AddressId2M

UkeyCproperty name Eno2M

Ucolumn name P Eno2BM

UBkeyCpropertyM

UkeyCproperty name P addno2M

Ucolumn name P Addno2BM

UBkeyCpropertyMUBcompositeCidM

Uproperty name P street2BM

Uproperty name P city2BMUproperty name P state2BMUBclassM

UhibernateOmappinM

&he followin java application to store the data into data base server

creatin the emp obj.


59/691

1. AddressId obj'. Address obj). "all save method for emp.address

&o establish the relationship between tables we do it based on the data

available in the tables. &hey are:

1. =ne to many'. (any to one). =ne to one+. (any to many

&o establish the relationship between tables we do it based on the data

available in the tables.

"ne to man relationship:

&o identify the relationship between the two tables we use the data

based on the data available in the tables develop a hibernate application

which uses oneCtoCmany relationship bBw emp and address table. &he

followin of the two tables are created by emp and address.

create table emp-Eno number-/! *ame varchar'-'! salary

number-1!'N

create table emp add primary key-EnoN

create table address-Aid number-/! Eno number-/! Addno number-/!

city varchar'-1N

alter table address add primary key-AidN

create table address-Aid number-/ primary key! Eno number-/

references emp-Eno

when we enerate hbm 3les and 7=0= classes we ot two hbm 3les and

7=0= classes. &he followin is the 7=0= class from emp table.

public class empR alter table address add

Inteer EmpN forein key-Eno references


60/691

#trin nameN emp-EnoN

Double salaryN

#ent address P new Hash#et-N

BBprovide settin and etters

S

&he followin is the con3uration of the Emp.hbm.5ml represents the

many relationship.

UhibernateOmappinM

Uclass name P info.inetsolv.Emp2M

Uid name P Eno2BM

Uproperty name P name2BM

Uproperty name P salary2BM

Uset name P address2 inverse P true2M

UkeyM

Ucolumn name P E*=2BM

UBkeyM

UoneCtoCmany class P info.inetsolv.Address2BM

UBsetM

UBclassM

UhibernateOmappinM

&he followin is the 7=0= class for Address table.

public class AddressR

Inteer aidN


61/691

Emp empN

Inteer addnoN

#trin streetN

#trin cityN

#trin stateN

BB provide settress and ettress

S

&he followin hbm 3le for address table.

UhibernateOmappinM

Uclass name P info.inetsolv.Address2M

Uid name P aid2BM

UmanyCtoCone name P E(72 class P info.inetsolv.Emp2M

Ucolumn name P E*=2BM

UBmanyCtoConeM

Uproperty name P addrno2BM

Uproperty name P street2BM

Uproperty name P city2BM

Uproperty name P state2BM

UBclassM

UBhibernateOmappinM

8enerally IDE reconiXe the relationship between tables and enerate

hbm 3les and 7=0= classes. Hibernate understand the relationship

between the tables based on the tas which are available in hbm 3le. &o


62/691

represent many relationship in hibernate we use collection objects. &he

followin are collection objects of hibernate.

?ist #et (ap $a

&hese collection objects represents many relationships we use hibernate

from the java side we have to create the objects store the data intoobjects and establish circular relationship.

one

Emp Address

Hashtable

&he followin java application to store the data into emp as well as

address table.

public class storeR

public static void main-#trin strVWR#ession h P Hibernate#[email protected]#ession-N

&ransaction t5 P h.bein&ransaction-N

Emp e P new Emp-N

e.#etEno-1N

e.#et*ame-*aidu2N

e.#et#alary-1!N

Eno P null

*ame P null#alary P

null

Address

#iXe P1

Emp

aid P nullaAddrno P

null

city P null

state P

null


63/691

Address a P new Address-N

a.#etAid-1N

a.#etEmp-eN

a.#etAddno-1N

a.#et"ity-HD2N

a.#et#tate-A72N#et s P e.etAddress-N

s.add-aN

h.#ave-eN

h.et&ransaction."ommit-N

Hibernate#ession@actory."lose#ession-N

4hen we call save-e hibernate can 3nd the relationship between thetables and store the data into dependent on tables to do this we must

specify two attributes inverse and cas code.

U#et CCCCCCCCCCC inverse P true2 cascade P all2BM

Develop a java application to retrieve the data from emp table who emp

no is ' -we would like to retrieve the correspondin address details.

Hibernate checks two strateies to retrieve the record from data base

server.

1. ?aXy loadinCCCCCCM Arisive -eaer loadin.

4hat is laXy loadinL

4hen ever we perform can operation on one table and table has

relationship with other tables and then we called a load method it will

retrieve the data from that table only.

Hibernate retrieve the records from child table when even any operation

is carried out of any other table. $y default hibernate uses laXy

loadin-true.

4hat is Aressive loadinL

4hen ever we call a load method on a parent table it will try to retrieve

record form child table also even thouh user doesn6t access any

properties. How to make hibernate as aressive we have to con3ure

laXy P false2 in hbm 3le of parent table.


64/691

Uset CCCCCCCCCC inverse P true2 laXy P false2M

UBsetM

&he followin is the e5ample of retrieve the data from data base server

by usin the load- method which is loadin the relationship.

public class ,etrieveR

public static void main-#trin arsVWR#ession s P Hibernate#[email protected]#ession-N

Emp e P new Emp-N

e.etEno-N

e.et*ame-N

e.et#alary-N

#et address P e.etAddress-N

#ystem.out.println-address.#iXe-N

Iterator i P addresses.iterator-Nwhile-i.has*e5t-N

Address a P -Addressi.ne5t-N

#ystem.out.println-a.etAid-N

#ystem.out.println-a.etAddno-N

#ystem.out.println-a.et"ity-N

S

Hibernate#[email protected]#ession-N

SAs part of 7=0= classes and hbm 3le instead of set we can use only

hibernate type ?ist! map! set! ba.

Ex: 4e are usin the list in the emp table is shown below.

public class EmpR

Inteer enoN

#trin nameN

Double salaryN

?ist address P new Array?ist-N

S

&he followin con3uration of Emp.hbm.5ml

UhibernatOmappinM

Uclass name P info.inetsolv.emp2M

Uid name P Eno2BM

Uproperty name P name2BM


65/691

Uproperty name P salary2BM

Ulist name P address2 inverse P


66/691

=rder table

man9to9one: 4e would like to maintain the tables for multiple

employees we would like to have departments and there are

departments with out employees to achieve we use manyCtoCone

relationship.

Emp

Dept

one9to9one relationship:

4e would like to maintain oneCtoCone relationship

between team and captain tables. &he followin are two takes which we

are usin to achieve this.

&eam

"aptain

Note: 4hen we create the above two tables and establish the

relationships and enerate hbm 3les and 7=0= classes IDE as unC

necessarily created oneCtoCmany relationship this is because of addin a

forein key relationship between captain and team table.

1. "reate two tables team and captain with only primary key do not

add the forein in the beinnin this is because if we had a forein

key IDE will enerate oneCtoCmany relationship.'. 8enerate hbm 3les and 7=0= classes.

Eno-pk name

Did-pk

&id-pk name

location

&id-pk -pk

"name


67/691

). 4e have to add oneCtoCone relationship between team and captain

by usin properties

UhibernateCmappinM

Uclass . . . . M

. . . . . . . . .

UoneCtoCone name P captain2 class P info.inetsolv.captain2

cascade P all2M

UBoneCtoConeM

UBclassMUBhibernateCmappinM BBteam.hbm.5ml

#imilar to team 7=0= class and hbm 3le! develop captain java and

captain.hbm.5ml

Develop the hibernate application to store data in to data base server.

public class #tore&eamDetailsR


#ession hsession P Hibernate#[email protected]#ession-N&ransaction t5 P hsession.bein&ransactions-N

&eam t P new &eam-N

t.set&id-tidN

t.set*ame-team*ameN

t.set?ocation-locationN

"aptain c P new "aptain-N

c.set&id-tidN

c.set*ame-captainN

c.set&eam-tN

t.set"aption-cN

hsession.save-cN

t5.commit-N

Hibenate#[email protected]#ession-N

S


68/691

S

man9to9man:

4e would like to implement manyCtoCmany relationship bBw student

and course tables.

BBstudent BBcourse

BBstudentCcourse

&o specify the manyCtoCmany relationship bBw the tables we have to

provide the followin con3uration in hbm 3les.

Uset name P #tudent"ourses2 table P #tudentO"ourse2 "as"ode P

all2 inverse P true2MUkey column P #id2BM

UmanyCtoCmany column P cid2 class P info.inetsolv.course2BM

UBsetM BBstudent.hbm.5ml

&he followin is the java code to store data in the data base server.

public class #toreDataR


#ession hession P Hibernate#[email protected]#ession

hibernate (1) notes

Documents