5 Steps to connect to the database in java

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

1) Register the driver class

The forName() method of Class class is used to register the driver class. This method is used to dynamically load the driver class.

 
public static void forName(String className)throws ClassNotFoundException

				

Example to register the OracleDriver class

 

Class.forName("oracle.jdbc.driver.OracleDriver");

2) Create the connection object

getConnection():- method of driver manager class is used this par page to obtain connection object.

Syntax of getConnection() method

 

 public static Connection getConnection(String url)throws SQLException  
 public static Connection getConnection(String url,String name,String password)  throws SQLException

each driver need some information in order to create the connection the database this information is call URL different driver required different information in hence format of URL varies from driver to driver in case of type1 JDBC driver URL has following format.

Example to establish connection with the Oracle database

 

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


3) Create the Statement object

The createStatement() 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) Execute the query

The executeQuery() 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) Close the connection object

close():- close method of connection interface is used this parpage.

Syntax of close() method

 

 public void close()throws SQLException

Example to close connection

 
con.close();