Use Preparedstatement to select and display recorded JDBC programs

Prior to JDBC tutorial , We get it PreparedStatement object , Later, we developed a Java Program to insert records into the table , And another program to Update table records . Now? , In this article , We will release a Java Program to use PreparedStatement Object selection and display records .

To get the records of the table , We need to ResultSet Object and use ResultSet Of getXxx(-) Method , We can get the details of the table .

We are using Oracle database , But you can use any database with the required information . stay Oracle In the database , We have a product list , It includes products ID、 The product name 、 Details of product price and quantity .

SQL> SELECT * FROM product;

PID   PNAME    PRICE   QUANTITY
----- -------- ------- ----------
 102  Bed      2000     1
2051  Fan       999     2
 111  Table    1500     1

SQL> DESC product;

Name      Null?    Type
--------- -------- ----------
PID       NOT NULL NUMBER(10)
PNAME              VARCHAR2(15)
PRICE              FLOAT(126)
QUANTITY           NUMBER(10)

We want to display the records of the product table . therefore , There is no need to get any input value from the end user , There is no need to set query parameters .

The required SQL Query is ,

SQL> SELECT pid, pname, price, 
     quantity FROM product;

Be careful ：- Developing JDBC Application time , Not recommended in SQL Use in query *, Therefore, it is not recommended to use .SELECT * FROM product

---

Show table records Java Program

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DisplayProductTable {

   // SQL query
   private static final String SELECT_PRODUCT_QUERY = 
       "SELECT PID, PNAME, PRICE, QUANTITY FROM PRODUCT";

   public static void main(String[] args ) {

      // declare variables
      Connection con = null;
      PreparedStatement ps = null;
      ResultSet rs = null;

      try {
         // establish the connection
         con = DriverManager.getConnection(
           "jdbc:oracle:thin:@localhost:1521:knowprogram",
           "scott", "tiger");

         // compile SQL query and 
         // store it in PreparedStatemet object
         if(con != null)
         ps = con.prepareStatement(SELECT_PRODUCT_QUERY);

         // execute the query
         if(ps != null) {
            rs = ps.executeQuery();
        }

        // process the result
        if(rs != null) {
           while(rs.next()) {
              System.out.println(""
                    + rs.getInt("PID") +" "
                    + rs.getString("PNAME") +" "
                    + rs.getFloat("PRICE") +" "
                    + rs.getInt("QUANTITY"));
           } 
        } 

        System.out.println("\nRecords displayed");

     } catch(SQLException se) {
        se.printStackTrace();
     } catch(Exception e) {
        e.printStackTrace();
     } // end of try-catch block 

     finally {
        // close JDBC objects
        try {
           if(ps != null) ps.close();
        } catch(SQLException se) {
           se.printStackTrace();
        }
        try {
           if(con != null) con.close();
        } catch(SQLException se) {
           se.printStackTrace();
        }
     }

   } //end of main
} //end of class

Output ：-

102 Bed 2000.0 1
2051 Fan 999.0 2
111 Table 1500.0 1

Records displayed

Use PreparedStatement Select and display records according to the given values

Now let's develop another JDBC Program , It will select rows based on the given value and display only the details of those rows .

Essential SQL Inquire about ,

SQL> SELECT pname, price, quantity 
     FROM product WHERE pid = 102;

PNAME   PRICE      QUANTITY
------- ---------- ----------
Bed     2000       1

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Scanner;

public class SelectTest {

   // SQL query
   private static final String SELECT_PRODUCT_QUERY = 
        "SELECT PNAME, PRICE, QUANTITY FROM PRODUCT"+
        " WHERE PID = ?";

   public static void main(String[] args ) {

      // declare variables
      Scanner scan = null;
      int pid = 0;
      Connection con = null;
      PreparedStatement ps = null;
      ResultSet rs = null;
      boolean flag = false;

      try {
    	 // read input
    	 scan = new Scanner(System.in);
    	 if(scan != null) {
    	    System.out.print("Enter product ID: ");
    	    pid = scan.nextInt();
    	 }

         // establish the connection
         con = DriverManager.getConnection(
            "jdbc:oracle:thin:@localhost:1521:knowprogram",
            "scott", "tiger");

         // compile SQL query and 
         // store it in PreparedStatemet object
         if(con != null)
         ps = con.prepareStatement(SELECT_PRODUCT_QUERY);

         // set input value to query parameter
         if(ps != null)
            ps.setInt(1, pid);

         // execute the query
         if(ps != null) 
            rs = ps.executeQuery();

         // process the result
         if(rs != null) {
           while(rs.next()) {
              flag = true;
              System.out.println(""
                 + rs.getString("PNAME") +" "
                 + rs.getFloat("PRICE") +" "
                 + rs.getInt("QUANTITY"));
           }
        }

        if(flag)
        System.out.println("Records fetched & displayed");
        else
        System.out.println("Records not found");

     } catch(SQLException se) {
        se.printStackTrace();
     } catch(Exception e) {
        e.printStackTrace();
     } // end of try-catch block 

     finally {
        // close JDBC objects
        try {
           if(ps != null) ps.close();
        } catch(SQLException se) {
           se.printStackTrace();
        }
        try {
           if(con != null) con.close();
        } catch(SQLException se) {
           se.printStackTrace();
        }
        try {
           if(scan != null) scan.close();
        } catch(Exception e) {
           e.printStackTrace();
        }
    }

  } //end of main
} //end of class

Output ：-

Enter product ID: 102
Bed 2000.0 1
Records fetched & displayed

Enter product ID: 1000
Records not found

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