CONNECTIVITY WITH ORACLE

How to send SQL statement to database ?

JDBC provide statement objects in order to send SQL statements to database. JDBC provides 3 type of statement objects -

1. Statement
2. PreparedStatement
3. CallableStatement

Statement : It is an interface implemented by JDBC driver developer. Statement is used for sending static SQL statements.

What is static SQL statement ?

An SQL statement with values, which is compiled every-time before execution.

How to create Statement object ?

Connection provide the following method which return Statement object.

Statement createStatement() ---- creates a Statement object for sending SQL statements to the database.

Example - 

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.SQLException;

import java.sql.Statement;

public class Test4 {

public static void main(String[] args) throws ClassNotFoundException, SQLException {

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

Connection con = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl", "scott", "rakesh");

System.out.println(con);

Statement st = con.createStatement();

System.out.println(st);

con.close();

}

}

Output -

oracle.jdbc.driver.T4CConnection@4ccabbaa

oracle.jdbc.driver.OracleStatementWrapper@6bf256fa

Methods of Statement

1. int executeUpdate(String sql) - Executes the given SQL statement, which may be an INSERT, UPDATE or DELETE statement or an SQL statement that returns nothing, such as SQL DDL statement.

2. ResultSet executeQuery(String sql) - Executes the given SQL statement, which returns a single ResultSet object.

3. boolean execute(String sql) - Executes the given SQL statement, which may return multiple results.