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How to move the ResultSet cursor to the first row in JDBC?
Whenever we execute SQL statements using the executeQuery() method, it returns a ResultSet object which holds the tabular data returned by the SELECT queries(in general).
The ResultSet object contains a cursor/pointer which points to the current row. Initially this cursor is positioned before first row (default position).
You can move the cursor of the ResultSet object to the first row from the current position, using the first() method of the ResultSet interface.
rs.first()
This method returns a boolean value specifying whether the cursor has been moved to the first row successfully.
If there are no rows in the current ResultSet object this method returns false, else it returns true.
Let us create a table with name tutorials_data in MySQL database using CREATE statement as shown below −
CREATE TABLE tutorials_data ( tutorial_id INT, tutorial_title VARCHAR(100), tutorial_author VARCHAR(40), submission_date date, PRIMARY KEY (tutorial_id) );
Now, we will insert 5 records in tutorials_data table using INSERT statements −
insert into tutorials_data values(1, 'Java', 'Krishna Kasyap', DATE('2019-09-01'));
insert into tutorials_data values(2, 'JFreeCharts', 'Satish Kumar', DATE('2019-05-01 '));
insert into tutorials_data values(3, 'JavaSprings', 'Amit Tiwari', DATE(' 2019-05-01'));
insert into tutorials_data values(4, 'Android', 'Sai Ram', DATE('2019-03-01'));
insert into tutorials_data values(5, 'Cassandra', 'Pruthvi Raj', DATE(' 2019-04-06'));In the following JDBC program we have established connection with the database and retrieved the contents of the table named tutorials_data into a ResultSet object, initially the cursor in this object will be at the default position (before first row), using the first() method we have moved the cursor from default position to first row and, displayed the contents it.
Example
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class RSCursor_first {
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/mydb";
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 tutorials_data";
//Executing the query
ResultSet rs = stmt.executeQuery(query);
//Moving the cursor from default position to 1st row.
rs.first();
System.out.println("Contents of the first record: ");
//Current record details.
System.out.print("ID: "+rs.getInt("tutorial_id")+", ");
System.out.print("Title: "+rs.getString("tutorial_title")+", ");
System.out.print("Author: "+rs.getString("tutorial_author")+", ");
System.out.print("Submission date: "+rs.getDate("submission_date"));
}
}Output
Connection established...... Contents of the first record: ID: 1, Title: Java, Author: Krishna Kasyap, Submission date: 2019-09-01
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