Unit 5.pdf

ODBC
• Open Database Connectivity
• A standard or open application programming interface
(API) for accessing a database.
• ODBC provides a C interface for database access on
Windows environment.

JDBC
• JDBC stands for Java Database Connectivity.
• It is a standard Java API for connecting programs written in Java to
the data in relational databases.
• JDBC works with Java on a variety of platforms, such as Windows,
Mac OS, and the various versions of UNIX.

JDBC Driver
• JDBC Driver is a software component that enables java
application to interact with the database.
• There are 4 types of JDBC drivers:
 JDBC-ODBC bridge driver
 Native-API driver (partially java driver)
 JDBC-Net pure Java/ Network-Protocol driver (fully
java driver)
 Pure Java Driver /Thin driver / Database-Protocol
driver(fully java driver)

JDBC-ODBC bridge driver
• The JDBC type 1 driver, also known as the JDBC-ODBC bridge driver.
• The JDBC-ODBC bridge driver uses ODBC driver to connect to the database.
The JDBC-ODBC bridge driver converts JDBC method calls into the ODBC
function calls.
• Advantages
• It allows us to communicate with all databases that supports ODBC driver
• It is vendor independent driver
• Disadvantages
• This driver is not portable because it is not written fully in Java.
• The performance is solver

Native API driver
• The JDBC type 2 driver, also known as the Native-API driver
• The Native API driver uses the client-side libraries of the database.
• The driver converts JDBC method calls into native calls of the database API.
• It is not written entirely in java.
• Advantages:
• Communicates faster as compared to type-1 Driver
• Contains additional features provided by specific database vendor
• Disadvantages:
• Mostly outdated
• Not thread safe
• If we change database need to change native api

JDBC-Net pure Java Driver
• The JDBC type 3 driver, also known as the Pure Java driver for database
middleware. It is a database driver implementation which makes use of a
middle tier between the calling program and the database.
• The middle-tier (application server) converts JDBC calls directly or indirectly into
a vendor-specific database protocol.
• It is fully written in java.

Type -3 [All java/ net protocol Driver ]
Advantages
1. No need for vendor specific library
2. Driver is written fully in java so portable
3. Suitable for web application
4. Type-3 driver so very small and fast to load
5. Driver is very flexible and allows access to multiple database using single driver.
Disadvantages:
1. Require another server application to install and maintain
2. Traversing the records may take longer ,since data comes through the backend

Thin driver
• The JDBC type 4 driver, also known as the Direct to Database Pure
Java Driver, is a database driver implementation that converts JDBC calls
directly into a vendor- specific database protocol.That is why it is known as thin
driver.
• It is fully written in Java language.

Type-4 Driver .
Advantages
1. Completely written in java so portable .
2. Most suitable for web applications
3. No of translation layer is less so performance is good.
4. Don’t need to install specific software on client or server.
Disadvantages
With type -4 drivers, user needs a different driver for each database.

JDBC two tier model
• In a two-tier model, a Java application communicates directly
with the database, via the JDBC driver.

• In a three-tier model, a Java application communicates with a middle tier
component that functions as an application server. The application server
talks to a given database using JDBC.
JDBC three tier model

Java.sql classes
Date : A thin wrapper around a millisecond value that allows JDBC to identify this as an
SQL DATE value.
DriverManager : The basic service for managing a set of JDBC drivers.
NOTE: The DataSource interface, new in the JDBC 2.0 API, provides another way to connect
to a data source.
DriverPropertyInfo : Driver properties for making a connection.
SQLPermission : The permission for which the SecurityManager will check when code that
is running an application with a SecurityManager enabled.
Time: A thin wrapper around the java.util.Date class that allows the JDBC API to identify this
as an SQL TIME value.
Timestamp: A thin wrapper around java.util.Date that allows the JDBC API to identify this as
an SQL TIMESTAMP value.
Types: The class that defines the constants that are used to identify generic SQL types,
called JDBC types.

Interfaces in java.sql package

Common JDBC Components
• The JDBC API provides the following interfaces
and classes −
• DriverManager Class
• Driver Interface
• Connection Interface
• Statement Interface
• ResultSet Interface

DriverManager Class
• The DriverManager class acts as an interface between user
and drivers.
• before interacting with a Database, it is a mandatory process
to register the driver; otherwise, an exception is thrown.
• It keeps track of the drivers that are available and handles
establishing a connection between a database and the
appropriate driver.
• The DriverManager class maintains a list of Driver classes that
have registered themselves by calling the method
DriverManager.registerDriver().
Common JDBC Components

Method Description
public static void registerDriver(Driver driver); is used to register the given driver
with DriverManager.
public static void deregisterDriver(Driver driver);
is used to deregister the given
driver (drop the driver from the
list) with DriverManager.
public static Connection getConnection(String url); is used to establish the connection
with the specified url.
public static Connection getConnection(String
url,String userName,String password);
is used to establish the connection
with the specified url, username
and password.
Commonly used methods of DriverManager class

• Driver Interface
This interface handles the communications with the database
server.
You will very rarely interact directly with Driver objects.
Instead, you use DriverManager objects, which manages
objects of this type.
It also abstracts the details associated with working with
Driver objects.

• Connection Interface
It helps to establish a connection with the database.
A Connection is a session between a Java application and a database.
The Connection interface is a factory of Statement, PreparedStatement, and
DatabaseMetaData.

Commonly used methods of Connection interface
Method Description
public Statement createStatement(); creates a statement object that can be used to
execute SQL queries.
public void setAutoCommit(boolean
status);
It is used to set the commit status. By default
it is true.
public void commit(); It saves the changes made since the
previous commit/rollback permanent.
public void rollback(); Drops all changes made since the
previous commit/rollback.
public void close();
closes the connection and Releases a
JDBC resources immediately.

• Statement Interface
The Statement interface provides methods to
execute queries with the database.
It provides factory method to get the object
of ResultSet.

Method Description
public ResultSet executeQuery(String sql); used to execute SELECT query. It returns
the object of ResultSet.
public int executeUpdate(String sql); used to execute specified query, it may be
create, drop, insert, update, delete etc.
public boolean execute(String sql); used to execute queries that may return
multiple results.
public int[] executeBatch(); used to execute batch of commands.
Commonly used methods of Statement interface

• ResultSet Interface
The object of ResultSet maintains a cursor
pointing to a particular row of data.
Initially, cursor points to before the first row.

Method Description
public boolean next(); is used to move the cursor to the one row next from the
current position.
public boolean previous(); is used to move the cursor to the one row previous from
the current position.
public boolean first(); is used to move the cursor to the first row in result set
object.
public boolean last(); is used to move the cursor to the last row in result set
object.
public boolean absolute(int row); is used to move the cursor to the specified row number in
the ResultSet object.
public int getInt(int columnIndex); is used to return the data of specified column index of the
current row as int.
public int getInt(String columnName); is used to return the data of specified column name of
the current row as int.
public String getString(int columnIndex); is used to return the data of specified column index of the
current row as String.
public String getString(String columnName); is used to return the data of specified column name of
the current row as String.
Commonly used methods of ResultSet interface

Connecting to Database
• There are 5 steps to connect any java
application with the database in java using
JDBC. They are as follows:
1. Register the driver
2. Creating connection
3. Creating statement
4. Executing queries
5. Closing connection

1.Register the driver class
• Class.forName()
• method is used to register the driver class.
• This method is used to dynamically load the driver class.
• Syntax of forName() method
public static void forName(String className)throws ClassNotFoundException
• Example to register with JDBC-ODBC Driver
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

2. Creating connection
• The DriverManager .getConnection()
• method is used to establish connection with the database.
• Syntax of getConnection() method
public static Connection getConnection(String url)throws SQLException
public static Connection getConnection(String url,String name,String password) throws
SQLException
• Example establish connection with Oracle Driver
• Connection con= DriverManager. getConnection( “jdbc:lodbc:DemoDB”, “username”,
“Password”)

3. Creating statement
• The createStatement()
• It is a method of Connection interface is used to create statement.
• The object of statement is responsible to execute queries with the
database.
• Syntax of createStatement() method
public Statement createStatement()throws SQLException
• Example to create the statement object
Statement stmt=con.createStatement();

4. Executing queries
• The executeQuery()
• It is a method of Statement interface is used to execute queries to the database.
• This method returns the object of ResultSet that can be used to get all the records of
a table.
• Syntax of executeQuery() method
public ResultSet executeQuery(String sql)throws SQLException
• Example to execute query
ResultSet rs=stmt.executeQuery("select * from emp");
while(rs.next())
{
System.out.println(rs.getInt(1)+" "+rs.getString(2));
}

5. Closing connection
• By closing connection object statement and ResultSet will be
closed automatically.
• The close() method of Connection interface is used to close
the connection.
• Syntax of close() method
public void close()throws SQLException
• Example to close connection
con.close();

Example to Connect Java Application
with mysql database

//program to create database
public class MyClass {
public static void main(String[] args) {
try {
Class.forName("com.mysql.cj.jdbc.Driver");
Connection con =
DriverManager.getConnection("jdbc:mysql://localhost:3306","root","gpnanded" );
Statement stmt = con.createStatement();
int isCreated = stmt.executeUpdate("CREATE DATABASE AJP_DATABASE");
con.close();
}catch(Exception e){ System.out.print(e); }
} //main close
} //class close

public class CreateTableProgram {
try {
Connection con =
DriverManager.getConnection("jdbc:mysql://localhost:3306/AJP_DATABASE","root","gpnand
ed" );
int isCreated = stmt.executeUpdate("CREATE TABLE Employee1(Roll_no int , Name
varchar(20) , phone_no int)");
System.out.print("table created ");
con.close();
}catch(Exception e){System.out.print(e);}
}
}

public class DataInsertProgram {
try {
Connection con =
DriverManager.getConnection("jdbc:mysql://localhost:3306/AJP_DATABASE", "root",
"gpnanded");
int isCreated = stmt.executeUpdate("INSERT INTO student values (101,'Prashant',000)");
con.close();
} catch (Exception e) {System.out.print(e);}
}
}

import java.sql.*;
class MysqlCon{
public static void main(String args[])
{
Try
{
Class.forName("com.mysql.jdbc.Driver");
Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/sun","root","root");
//here sun is database name, root is username and password
Statement stmt=con.createStatement();
ResultSet rs=stmt.executeQuery("select * from emp");
while(rs.next())
System.out.println(rs.getInt(1)+" "+rs.getString(2)+" " + rs.getString(3));
con.close();
}
catch(Exception e){System.out.println(e);}
}
}

Unit 5.pdf

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Unit 5.pdf