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Java ResultSet findColumn() 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 findColumn() method of the ResultSet interface maps the column label to column index. Using this you can find the index of a particular column in the result set.
This method accepts a String variable representing the column label and, returns an integer value representing the column index of the given column label.
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 example retrieves the contents of the MyPlayers table as a ResultSet object and, retrieves the index of the Date_Of_Birth column and displays it.
Example
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class ResultSet_findColumn {
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(ResultSet.TYPE_SCROLL_SENSITIVE,
ResultSet.CONCUR_UPDATABLE);
//Query to retrieve records
String query = "Select * from MyPlayers";
//Executing the query
ResultSet rs = stmt.executeQuery(query);
//Retrieving the index of a column
int column_index = rs.findColumn("Date_Of_Birth");
System.out.println("Index of the coulmn named Date_Of_Birth is: "+column_index);
}
}Output
Connection established...... Index of the column named Date_Of_Birth is: 4
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