Ch. No Name Marks

01 AWT 24

02 Networking 18

03 JDBC 20

04 Swing 18

05 Servlet 20

Advance Java Programming

2 IBM

Two-Tier Architecture

• Client connects directly to server

• e.g. HTTP

Advantage• Simple in Design• Easy to maintain and modify• Communication is fast

• Disadvantages:• Inflexible• Limited Client• Less secure• Cost ineffective

4 IBM

Three-Tier Architecture• Application Server

sits between client and database

User Interface

UI Logic

Business Logic

DatabaseTables

User DataDML OperationsValidationChecks

Database Server Layer

Client Layer

Application Server Layer

Business Messages

Netw

orkN

etwork

Advantage

• Flexible: one part can change without affecting other

• Can connect to different database• High performance• Data integrity improve• More secure• Can implement proxy and firewall

Disadvantages

• High Maintenance• High Complexity• Lower network efficiency

7

Java Application Database• The below given figure shows the Employee Logging System

application developed in Java interacting with the Employee database using the JDBC API:

EmpName

E-Mail Address

Employee Logging System

EmployeeLog

Name Email

RDBMS

JDBC API

Connects to

Submit Clear

8

It can be categorized into into two layers:

Java

Application

JDBC

API

Oracle

DB2

SQL Server

Driver

Driver

Driver

JDBC Application Layer JDBC Driver Layer

JDBC Architecture

9 IBM

JDBC Drivers

• Type I: “Bridge” -

• Type II: “Native” -

• Type III: “Middleware” -

• Type IV: “Pure” -

JDBC-ODBC Bridge Driver

Native-API Partly-Java Driver

JDBC-Net Pure-Java Driver

Native Protocol Pure-Java Driver

Overview of All Drivers

10 IBM

Type I Drivers• Use bridging technology

• Translates query obtained by JDBC into corresponding ODBC query, which is then handled by the ODBC driver.

• Almost any database for which ODBC driver is installed, can be accessed.

11 IBM

Disadvantage of Type-I Driver• Performance overhead since the calls have to

go through the JDBC overhead bridge to the ODBC driver, then to the native db connectivity interface.

• The ODBC driver needs to be installed on the client machine.

• Not good for Web

12 IBM

Type II Drivers• Native API drivers

• Better performance than Type 1 since no jdbc to odbc translation is needed.

• Converts JDBC calls into calls to the client API for that database.

13 IBM

Disadvantage of Type-II Driver• The vendor client library needs to be installed

on the client machine. • Cannot be used in internet due the client side

software needed. • The driver is compiled for use with the

particular operating system. • Not good for Web

14 IBM

Type III Drivers• Follows a three tier

communication approach.

• Calls middleware server, usually on database host

• Very flexible -- allows access to multiple databases using one driver

• Only need to download one driver

15 IBM

Disadvantage of Type-III Driver• Requires database-specific coding to be done

in the middle tier.

• An extra layer added may result in a time-bottleneck.

16 IBM

Type IV Drivers• 100% Pure Java --

Communicate directly with a vendor’s database through socket connection

• Use Java networking libraries to talk directly to database engines

17 IBM

Disadvantage of Type-IV Driver• At client side, a separate driver is needed for

each database

18 IBM

JDBC Process

1. Loading JDBC Driver2. Connect to Dbms3. Create Statement object4. Query execution5. Process the result6. Connection termination

java.sql package required

19 IBM

Loading Driver• User must create database and added under

DSN in control panel

• JDBC driver must be loaded or registered before connecting to dbms

• Class. forName (“sun.jdbc.odbc.JdbcOdbcDriver”)

20 IBM

Connecting to database• DriverManager class is use to make connection

to database through DSN

• Result is stored in object of Connection class

• DriverManager.getConnection(“ jdbc: odbc:DSN name”)

• DriverManager.getConnection (“jdbc:odbc:DSN name”, String username, String password)

21 IBM

Create statement object• Statements are used to execute sql queries

• Three types of statement: Statement PreparedStatement CollableStatement • Connection class object use to create

staement• Statement objectname = connection class

object.createStataemnt()

22 IBM

Query execution• SQL queries are executed to perform

operations on database like insert, select etc.

• It returns ResultSet class object through which database is accessed.

23 IBM

Process the result• Different methods are use to accessed rows and

columns of table.

• getX() method is use to obtain value of column of perticular row.

• getX( column index/name)

• X may be Int, Float, Boolean, String etc.• e.g. getInt(2)

24 IBM

Connection termination

• Connection are closed using close method.

25 IBM

Methods of Statement class

• ExecuteQuery()- It used to obtain information form database. Select query is used for this method.

Returntype is Object of resultset class

e.g. executeQuery(“select * from tablename”)

26 IBM

Methods of Statement class

• ExecuteUpdate()- It used to perfrom operation on database. Insert, update, delete query is used for this method.

Returntype is integer which represent total number of rows affected

e.g. executeUpdate(“insert into tablename values”)

27 IBM

Methods of Statement class

• Execute()- It used to perform any type operation on database.

Return type is BooleanIf value is true then result stored in resultset object and

if value is false then result stored in integer.

If true execute getResultSet() and false execute getUpdateCount() method

e.g. execute(“insert into tablename values”)

28 IBM

ResultSet

• This class provides method to access data generated by query in table

• setX is main method

• getRow()method use to count total rows

29 IBM

ResultSet• Scrollable resultset will move backward or forward

• first()• last()• next()• absolute (int position) • relative(+- int position) Returntype of all methods are boolean

To use methods other than next following constants are used ResultSet.TYPE-Scroll_SENSITIVE ResultSet.CONCUR_UPDATABLE

30 IBM

PreparedStatement• Query precompiled• ? Given on the place of value• PreparedStatement

objname=connectionobjname.prepareStatement(String query)

• Value of ? Set using setX method• setX(? Position, Value)• e.g. setInt(1,10)

31 IBM

CallableStatement• Call stored procedures stored in jdbc

application program• It use three parameter:IN- Input data to procedureOUT- Data return by procedureINOUT- Input as well as output data

32 IBM

MetaData• Infromation describe Database or

Resultset • Types: DatabaseMetaDataDatabaseMetaData objname=

Connectionobjname.getMetaData()ResultSetMetaDataResultSetMetaData objname=

ResultSetobjname.getMetaData()

33 IBM

DatabaseMetaData methods

• getDatabaseProductVersion()• getURL()• getDatabaseProductName()• getDriverName()• getUserName()

34IBM

ResultSetMetaData methods

• getColumnCount()• getColumnName(int position)• getColumnType(int position) rt: int• getTableName(int columnposition)• getColumnDisplaySize(int columnposition)• getColumnTypeName(int position)

35IBM

Exception

• SQL Exception: if query wrong then exception generated

• SQL Warning: Provide information about database access warning

• If data lost due to truncation then TruncationException is thrown