JDBC PreparedStatement Interface

The PreparedStatement interface is a subinterface of Statement. It is used to execute parameterized query.

Example: 

                        String sql="insert into emp values(?,?,?)";

As you can see, we are passing parameter (?) for the values. Its value will be set by calling the setter methods of PreparedStatement.

Why use PreparedStatement?

Improves performance: The performance of the application will be faster if you use PreparedStatement interface because query is compiled only once.

The prepareStatement() method of Connection interface is used to return the object of PreparedStatement. Syntax:


                        public PreparedStatement prepareStatement(String query)throws SQLException{}

PreparedStatement methods are:

  1. 1. public void setInt(int paramIndex, int value): sets the integer value to the given parameter index.
  2. 2. public void setString(int paramIndex, String value): sets the String value to the given parameter index.
  3. 3. public void setFloat(int paramIndex, float value): sets the float value to the given parameter index.
  4. 4. public void setDouble(int paramIndex, double value): sets the double value to the given parameter index.
  5. 5. public int executeUpdate(): executes the query. It is used for create, drop, insert, update, delete etc.
  6. 6. public ResultSet executeQuery(): executes the select query. It returns an instance of ResultSet.
Insert statement example using PreparedStatement

                        
                    package com.java.session.ninteen;

                    import java.sql.*;

                    public class PreparedStatementExample {
                        static final String DB_URL = "jdbc:mysql://localhost/emp";
                        static final String USER = "root";
                        static final String PASS = "PASSWORD";
                        static final String QUERY = "INSERT INTO EMP.EMPLOYEE VALUES(?,?,?,?)";
                        public static void main(String[] args) {
                            Connection con = null;
                            PreparedStatement pstmt = null;
                            try {
                                con = DriverManager.getConnection(DB_URL, USER, PASS);
                                pstmt = con.prepareStatement(QUERY);
                                pstmt.setInt(1, 14);
                                pstmt.setInt(2, 24);
                                pstmt.setString(3, "sadakhat");
                                pstmt.setString(4, "navab");
                                int result = pstmt.executeUpdate();
                                System.out.println(result + " record inserted");
                            } catch (SQLException se) {
                                se.printStackTrace();
                            } finally {
                                try {
                                    pstmt.close();
                                    con.close();
                                } catch (SQLException se) {
                                    se.printStackTrace();
                                }
                            }
                        }
                    }