DatabaseMetaData

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

This interface provides method to find out information about the database product being used, Driver Information, Operation Supported by Database, Details of Table, Procedures, Sequence etc.

getMetaData() method of Connection interface is used to obtained the reference of database metadata object.

Commonly used methods:

getDriverName():Retrieves the name of this JDBC driver.

public String getDriverName() throws SQLException

getCatalogs():Retrieves the catalog names available in this database. The results are ordered by catalog name.

public ResultSet getCatalogs() throws SQLException

getTables():Retrieves a description of the tables available in the given catalog. Only table descriptions matching the catalog, schema, table name and type criteria are returned. They are ordered by TABLE_TYPE, TABLE_CAT, TABLE_SCHEM and TABLE_NAME.

public ResultSet getTables(String catalog, String schemaPattern, String tableNamePattern, String[] types) throws SQLException

Simple Example:

import java.sql.Connection;

import java.sql.DatabaseMetaData;

import java.sql.DriverManager;

import java.sql.ResultSet;

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();

            DatabaseMetaData dbm=con.getMetaData();

            System.out.println(dbm.getDriverName());

            ResultSet set=dbm.getCatalogs();

            System.out.println("Available catalogs are:");

            System.out.println("-----------------");

            while(set.next()){

            System.out.println( set.getString(1));

           }

            System.out.println("----------------");

            // Third field of the ResultSet return by the getTables() methods contain the name of the tables.

            ResultSet rrset=dbm.getTables(null, null, null, new String[]{"TABLE"});

            System.out.println("Tables in stu database");

            System.out.println("-----------------");

            while(rrset.next()){

            System.out.println(rrset.getString(1)+" "+rrset.getString(3));

           }

            System.out.println("---------------");

          

        } 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:

MySQL-AB JDBC Driver

Available catalogs are:

-----------------

information_schema

mysql

performance_schema

stu

test

----------------

Tables in stu database

-----------------

stu person

stu student

---------------