JDBC 4.0 API in java

JDBC 4.0 API in java

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JDBC 4.0 API

JDBC 4.0 API is mainly divided into two package

1. java.sql
2. javax.sql

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java.sql package

This package includes classes and interfaces to perform almost all JDBC operation such as creating and executing SQL Queries.

Important classes and interface of java.sql package

classes/interface	Description
java.sql.BLOB	Provide support for BLOB(Binary Large Object) SQL type.
java.sql.Connection	creates a connection with specific database
java.sql.CallableStatement	Execute stored procedures
java.sql.CLOB	Provide support for CLOB(Character Large Object) SQL type.
java.sql.Date	Provide support for Date SQL type.
java.sql.Driver	create an instance of a driver with the DriverManager.
java.sql.DriverManager	This class manages database drivers.
java.sql.PreparedStatement	Used to create and execute a parameterized query.
java.sql.ResultSet	It is an interface that provides methods to access the result row-by-row.
java.sql.Savepoint	Specify savepoint in a transaction.
java.sql.SQLException	Encapsulate all JDBC related exception.
java.sql.Statement	This interface is used to execute SQL statements.

javax.sql package

This package is also known as JDBC extension API. It provides classes and interfaces to access server-side data.

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Important classes and interface of javax.sql package

classes/interface	Description
javax.sql.ConnectionEvent	Provide information about the occurrence of an event.
javax.sql.ConnectionEventListener	Used to register event generated by the PooledConnection object.
javax.sql.DataSource	Represent the DataSource interface used in an application.
javax.sql.PooledConnection	provide an object to manage connection pools.

Steps to connect a Java Application to Database

The following 5 steps are the basic steps involve in connecting a Java application with Database using JDBC.

1. Register the Driver
2. Create a Connection
3. Create SQL Statement
4. Execute SQL Statement
5. Closing the connection

Register the Driver

Class.forName() is used to load the driver class explicitly.

Example to register with JDBC-ODBC Driver

Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

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Create a Connection

getConnection() method of DriverManager class is used to create a connection.

Syntax

getConnection(String url)
getConnection(String url, String username, String password)
getConnection(String url, Properties info)

Example establish a connection with Oracle Driver

Connection con = DriverManager.getConnection
                    ("jdbc:oracle:thin:@localhost:1521:XE","username","password");

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Create SQL Statement

createStatement() the method is invoked on the current Connection object to create a SQL Statement.

Syntax

public Statement createStatement() throws SQLException

Example to create a SQL statement

Statement s=con.createStatement();

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Execute SQL Statement

executeQuery() method of Statement interface is used to execute SQL statements.

Syntax

public ResultSet executeQuery(String query) throws SQLException

Example to execute a SQL statement

ResultSet rs=s.executeQuery("select * from user");
  while(rs.next())
  {
   System.out.println(rs.getString(1)+" "+rs.getString(2));
  }

Closing the connection

After executing the SQL statement you need to close the connection and release the session. The methodclose() of Connection interface is used to close the connection.

Syntax

public void close() throws SQLException

Example of closing a connection

con.close();