ResultSetMetaData

The simple meaning of metadata is data about data. There are two metadata available in the JDBC API - ResultSetMetaData and DatabaseMetaData.

This interface provide method to find out information such as number of columns return in the result set , name and types of column their source table etc.

getMetaData() method of ResultSet Interface is used to obtained the reference of ResultSetMetaData.

public  ResultSetMetaData getMetaData();

Methods of ResultSetMetaData:

getColumnCount():Returns the number of columns in this ResultSet object.

public int getColumnCount() throws SQLException

getColumnName():Get the designated column's name.

public String getColumnName(int column) throws SQLException

getColumnType():Retrieves the designated column's SQL type

public int getColumnType(int column) throws SQLException

getTableName():Gets the designated column's table name.

public String getTableName(int column) throws SQLException

getColumnTypeName():Retrieves the designated column's database-specific type name.

public String getColumnTypeName(int column) throws SQLException

Simple Example:

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.ResultSetMetaData;

import java.sql.SQLException;

import java.sql.Statement;

import java.util.logging.Level;

import java.util.logging.Logger;

/**

 *

 * @author Navindra Jha

 */

public class Main {

    /**

     * @param args the command line arguments

     */

    public static void main(String[] args) {

        try {

            Class.forName("com.mysql.jdbc.Driver");

            Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/stu","root","");

            Statement stmt=con.createStatement();

            ResultSet rset=stmt.executeQuery("select * from student");

            ResultSetMetaData rmdata=rset.getMetaData();

            System.out.println("Table : "+rmdata.getTableName(1)+" Database: "+rmdata.getCatalogName(1));

            System.out.println("Column_Name: Column_Type");

            for(int i=1;i<=rmdata.getColumnCount();i++){

                System.out.println(rmdata.getColumnName(i)+":        "+rmdata.getColumnTypeName(i));

            }

        } catch (SQLException ex) {

            Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);

        } catch (ClassNotFoundException ex) {

            Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);

        }

    }

}

Output:

Table : student   Database: stu

Column_Name: Column_Type

name:        VARCHAR

roll:            INT

marks:       INT