INTRODUCTION

Java Database Connectivity

Dr. Syed Imtiyaz HassanAssistant Professor, Deptt. of CSE,

Jamia Hamdard (Deemed to be University), New

Delhi, India.

s.imtiyaz@jamiahamdard.ac.in

Agenda

Introduction

Product Components

Architecture

Drivers

Processing SQL

Summary

Refrences

Java API

for

database-independent connectivity

between

the Java programming language

and

a wide range of databases

Introduction

Helps to write Java applications that manage these three

programming activities:

Connect to a data source, like a database

Send queries and update statements to the database

Retrieve and process the results received from the

database in answer to your query

Introduction

The JDBC API

java.sql

javax.sql

JDBC Driver Manager DataSource

JDBC Test Suite

JDBC-ODBC Bridge

Product Components

2-tier

3-tier

N-tier

Architecture

SRC: https://docs.oracle.com/javase/tutorial/jdbc/overview/index.html

Architecture … 2-tier

Client connects directly to server

e.g. HTTP, email

Pro:

simple

Con:

fat client

inflexible

Architecture … 2-tier (cont.)

SRC: https://docs.oracle.com/javase/tutorial/jdbc/overview/index.html

Architecture … 3-tier

Pros Flexible Specialization: presentation / business logic / data management Can cache queries Can implement proxies and firewallsCons Higher complexity Higher maintenance Lower network efficiency More parts to configure

Architecture … 3-tier (cont.)

N-tier data applications are data applications that are

separated into multiple tiers

Presentation Tier/Middle Tier/Data Tier

Adapted from:https://msdn.microsoft.com/en-us/library/bb384398.aspx

Architecture … N-tier

Type 1: JDBC-ODBC Bridge DriverType 2: JDBC-Native API

SRC: https://www.tutorialspoint.com/jdbc/jdbc-driver-types.htm

Drivers

Type 3: JDBC-Net pure Java (Network Protocol)Type 4: 100% pure Java (Native-protocol)

SRC: https://www.tutorialspoint.com/jdbc/jdbc-driver-types.htm

Driver (cont.)

Video

Simplicity is the ultimate sophistication.

Leonardo da Vinci

Simplest explanation is the right explanation.

Occam's razor

Everything must be made as simple as possible, but not simpler.

Albert Einstein

Simplicity

1. Establishing a connection.

2. Create a statement.

3. Execute the query.

4. Process the Result.

5. Close the connection.

Processing SQL

Create Statement

Close Connection

Establish Connection

Execute Query

Process Result

Processing SQL (cont.)

Register the driver

Connect to the database

Create Statement

Close Connection

Establish Connection

Execute Query

Process Result

Datasource

DriverManager

Processing SQL … Establish Connection

jdbc:<subprotocol>:<subname>

ProtocolDatabase

identifier

jdbc:mysql://localhost:3306/students

Subprotocol

Register Class.forName(drivername)

Connect DriverManager.getConnection(URL)

Processing SQL … Establish Connection (cont.)

class.forName(“com.mysql.jdbc.Driver”);

Connection

con=DriverManager.getConnection(“jdbc:mysql://localhost:3306/students”,

”root”,”passwd”);

Processing SQL … Establish Connection (cont.)

import java.sql.*;class Select {

public static void main( String argv[] ) {try {

Class.forName("com.mysql.jdbc.Driver");

String url = "jdbc:mysql://localhost:3306/students";

Connection con = DriverManager.getConnection(url, "root","password");

.

.

.

.

.

.} catch (Exception e) {

e.printStackTrace();}

}}

Processing SQL … Establish Connection (cont.)

Create Statement

Close Connection

Establish Connection

Execute Query

Process Result

Statement stmt = con.createStatement();

Processing SQL … Create Statement

Create Statement

Close Connection

Establish Connection

Execute Query

Process Result ResultSet rs = stmt.executeQuery(statement);

int count = stmt.executeUpdate(statement);

executeQuery()

ExecuteUpdate()

Processing SQL … Execute Query

ResultSet rset = stmt.executeQuery ("select *from BTCSE");

int rowcount = stmt.executeUpdate ("delete from BTCSE

where student_section = ‘A’);

Select statement

Delete statement

Processing SQL … Execute Query (cont.)

import java.sql.*;class Select {

public static void main( String argv[] ) {try {

Class.forName("com.mysql.jdbc.Driver");

String url = "jdbc:mysql://localhost:3306/students";

Connection con = DriverManager.getConnection(url, "root","password");

Statement stmt=con.createStatement();String sql = "select * from BTCSE";ResultSet rs=stmt.executeQuery(sql);

....

} catch (Exception e) {e.printStackTrace();

}}

}

Processing SQL … Execute Query (cont.)

Create Statement

Close Connection

Establish Connection

Execute Query

Process Result

ResultSet

Others

Processing SQL … Process Result

while (rs.next()) { … }

String val =

rs.getString(colname);

while (rset.next()) {

String enrollment = rset.getString(“enrollment_number");

String stdname = rset.getString(2);

… // Process or display the data

}

String val =

rs.getString(colIndex);

1. Step through the ResultSet.

2. Use getXXX() to get each column value.

Processing SQL … Process Result … ResultSet

import java.sql.*;class Select {

public static void main( String argv[] ) {try {

Class.forName("com.mysql.jdbc.Driver");

String url = "jdbc:mysql://localhost:3306/students";

Connection con = DriverManager.getConnection(url, "root","password");

Statement stmt=con.createStatement();String sql = "select * from students";

ResultSet rs=stmt.executeQuery(sql);

while ( rs.next() )System.out.println(rs.getString( 1 )+","+rs.getString( 2 ));……….

} catch (Exception e) {e.printStackTrace();

}}

}

Processing SQL … Process Result (cont.)

Close the ResultSet

Close the Statement

Close the Connection

Create Statement

Close Connection

Establish Connection

Execute Query

Process Result

Processing SQL … Close Connection

1. Close the ResultSet object.

2. Close the Statement object.

3. Close the connection.

rs.close();

stmt.close();

con.close();

Processing SQL … Close Connection (cont.)

package advancedjava.jdbc;

import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.Statement;

public class SelectRecords {public static void main(String argv[]) {

Connection con = null;Statement stmt = null;ResultSet rs = null;try {

Class.forName("com.mysql.jdbc.Driver");String url = "jdbc:mysql://localhost:3306/students";con = DriverManager.getConnection(url, "root", "password");String sql = "select * from btcse";stmt = con.createStatement();rs = stmt.executeQuery(sql);System.out.println("Enrollment\tName\tSection");while (rs.next()) {

System.out.println(rs.getString(1) + "\t" + rs.getString(2) + "\t" + rs.getInt(3));

}rs.close();stmt.close();con.close();

} catch (Exception e) {System.out.println("** Error on data select. ** " + e);

}}

}

Program Example

Summary

JDBC Database Access

https://docs.oracle.com/javase/tutorial/jdbc/index.html

Reference

Questions ???

Thank You