JDBC

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JDBC stands for Java Database Connectivity. JDBC is a Java API to connect and execute the query with the database. It is a part of JavaSE (Java Standard Edition). JDBC API uses JDBC drivers to connect with the database. There are four types of JDBC drivers:
  • JDBC-ODBC Bridge Driver,
  • Native Driver,
  • Network Protocol Driver, and
  • Thin Driver
STEPS FOR JDBC:

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.
Example to register the OracleDriver class
Class.forName("oracle.jdbc.driver.OracleDriver");  
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(  
"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
  
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
con.close(); 

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