มี 2 ประเภท คือ Forward only และ Bidirectional
Forward only ResultSet: cursor เคลื่อนที่ได้เพียงทิศทางเดียว เป็นค่าเริ่มต้นของ JDBC ใช้ next() วนลูป
while(rs.next()) { }
ตัวอย่าง Forward Only
ตาราง dataset:
+--------------+-----------+ | mobile_brand | unit_sale | +--------------+-----------+ | Iphone | 3000 | | Samsung | 4000 | | Nokia | 5000 | | Vivo | 1500 | +--------------+-----------+
โปรแกรมดึงข้อมูล:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
public class RetrievingData {
public static void main(String args[]) throws Exception {
DriverManager.registerDriver(new com.mysql.jdbc.Driver());
String mysqlUrl = "jdbc:mysql://localhost/TestDB";
Connection con = DriverManager.getConnection(mysqlUrl, "root", "password");
System.out.println("Connection established......");
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("select * from Dataset");
System.out.println("Contents of the table");
while(rs.next()) {
System.out.print("Brand: " + rs.getString("Mobile_Brand") + ", ");
System.out.print("Sale: " + rs.getString("Unit_Sale"));
System.out.println();
}
}
}
Connection established...... Contents of the table Brand: Iphone, Sale: 3000 Brand: Samsung, Sale: 4000 Brand: Nokia, Sale: 5000 Brand: Vivo, Sale: 1500
Bidirectional ResultSet: cursor เคลื่อนที่ได้ทั้งหน้า-หลัง สร้างด้วย createStatement() ที่รับ resultSetType และ concurrency:
Statement createStatement(int resultSetType, int resultSetConcurrency)
สร้าง bidirectional result set:
Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
ตัวอย่าง Bidirectional
ใช้ previous() พิมพ์จากหลังมาหน้า:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
public class BidirectionalResultSet {
public static void main(String args[]) throws Exception {
DriverManager.registerDriver(new com.mysql.jdbc.Driver());
String mysqlUrl = "jdbc:mysql://localhost/TestDB";
Connection con = DriverManager.getConnection(mysqlUrl, "root", "password");
System.out.println("Connection established......");
Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
ResultSet rs = stmt.executeQuery("select * from Dataset");
rs.afterLast();
System.out.println("Contents of the table");
while(rs.previous()) {
System.out.print("Brand: " + rs.getString("Mobile_Brand") + ", ");
System.out.print("Sale: " + rs.getString("Unit_Sale"));
System.out.println();
}
}
}
Connection established...... Contents of the table Brand: Vivo, Sale: 1500 Brand: Nokia, Sale: 5000 Brand: Samsung, Sale: 4000 Brand: IPhone, Sale: 3000
