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Java ResultSet relative() method with example
When we execute certain SQL queries (SELECT query in general) they return tabular data.
The java.sql.ResultSet interface represents such tabular data returned by the SQL statements.
i.e. the ResultSet object holds the tabular data returned by the methods that execute the statements which quires the database (executeQuery() method of the Statement interface in general).
The ResultSet object has a cursor/pointer which points to the current row. Initially this cursor is positioned before first row.
The relative() method of the ResultSet interface moves the ResultSet pointer/cursor n number of rows from the current position.
This method returns an integer value representing the current row number to which the ResultSet pointer points to.
Let us create a table with name MyPlayers in MySQL database using CREATE statement as shown below:
CREATE TABLE MyPlayers( ID INT, First_Name VARCHAR(255), Last_Name VARCHAR(255), Date_Of_Birth date, Place_Of_Birth VARCHAR(255), Country VARCHAR(255), PRIMARY KEY (ID) );
Now, we will insert 7 records in MyPlayers table using INSERT statements:
insert into MyPlayers values(1, 'Shikhar', 'Dhawan', DATE('1981-12-05'), 'Delhi', 'India');
insert into MyPlayers values(2, 'Jonathan', 'Trott', DATE('1981-04-22'), 'CapeTown', 'SouthAfrica');
insert into MyPlayers values(3, 'Kumara', 'Sangakkara', DATE('1977-10-27'), 'Matale', 'Srilanka');
insert into MyPlayers values(4, 'Virat', 'Kohli', DATE('1988-11-05'), 'Delhi', 'India');
insert into MyPlayers values(5, 'Rohit', 'Sharma', DATE('1987-04-30'), 'Nagpur', 'India');
insert into MyPlayers values(6, 'Ravindra', 'Jadeja', DATE('1988-12-06'), 'Nagpur', 'India');
insert into MyPlayers values(7, 'James', 'Anderson', DATE('1982-06-30'), 'Burnley', 'England');Following JDBC program establishes connection with the database, retrieves the contents of the table MyPlayers into a ResultSet object, retrieves the current position of the cursor moves it in forward and backward directions relatively.
Example
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class ResultSet_relative {
public static void main(String args[]) throws SQLException {
//Registering the Driver
DriverManager.registerDriver(new com.mysql.jdbc.Driver());
//Getting the connection
String mysqlUrl = "jdbc:mysql://localhost/mydatabase";
Connection con = DriverManager.getConnection(mysqlUrl, "root", "password");
System.out.println("Connection established......");
//Creating the Statement
Statement stmt = con.createStatement();
//Query to retrieve records
String query = "Select * from MyPlayers";
//Executing the query
ResultSet rs = stmt.executeQuery(query);
//Moving the cursor to 3rd position
rs.absolute(3);
System.out.println("Position of the pointer: "+rs.getRow());
//Moving the pointer 2 positions forward from the current
System.out.println("Position of the pointer after moving it to 2 places forward relatively: "+rs.relative(2));
//Moving the pointer 3 positions backwards from the current
System.out.println("Position of the pointer after moving it to 3 places backward relatively: "+rs.relative(-3));
}
}Output
Connection established...... Position of the pointer: 3 Position of the pointer after moving it to 2 places forward relatively: true Position of the pointer after moving it to 3 places backward relatively: true
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