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.
Syntax of forName() method
- public static void forName(String className)throws ClassNotFoundException
Example to register the OracleDriver class
2) Create the connection object
|The getConnection() method of DriverManager class is used to establish connection with the database.
Syntax of getConnection() method
- 1) public static Connection getConnection(String url)throws SQLException
- 2) public static Connection getConnection(String url,String name,String password)
- throws SQLException
Example to establish connection with the Oracle database
- Connection con=DriverManager.getConnection(
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”);
- System.out.println(rs.getInt(1)+” “+rs.getString(2));
5) Close the connection object
|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