JDBC Driver

import java.sql.*;

// request a Connection to a MonetDB server running on 'localhost' (with
// default port 50000) for database demo for user and password monetdb
Connection con = DriverManager.getConnection("jdbc:monetdb://localhost/demo", "monetdb", "monetdb");

import java.sql.*;

/*
 * This example assumes there exist tables a and b filled with some data.
 * On these tables some queries are executed and the JDBC driver is tested
 * on it's accuracy and robustness against 'users'.
 *
 * @author Fabian Groffen
 */
public class MJDBCTest {
    public static void main(String[] args) throws Exception {

        Connection con = null;
        Statement st = null;
        ResultSet rs = null;

        try {
            String con_url = "jdbc:monetdb://localhost:50000/mydb?so_timeout=10000";

            // make a connection to the MonetDB server using JDBC URL starting with: jdbc:monetdb://
            con = DriverManager.getConnection(con_url, "monetdb", "monetdb");

            // make a statement object
            st = con.createStatement();

            // execute SQL query which returns a ResultSet object
            String qry = """SELECT a.var1, COUNT(b.id) AS total
                            FROM a, b
                            WHERE a.var1 = b.id
                              AND a.var1 = 'andb'
                            GROUP BY a.var1
                            ORDER BY a.var1, total;
                         """
            rs = st.executeQuery(qry);

            // get meta data and print column names with their type
            ResultSetMetaData md = rs.getMetaData();
            final int colCount = md.getColumnCount();
            for (int i = 1; i <= colCount; i++) {
                System.out.print(md.getColumnName(i) + ":" + md.getColumnTypeName(i) + "\t");
            }
            System.out.println("");

            // now print the data: only the first 5 rows, while there probably are
            // a lot more. This shouldn't cause any problems afterwards since the
            // result should get properly discarded when we close it
            for (int i = 0; rs.next() && i < 5; i++) {
                for (int j = 1; j <= colCount; j++) {
                    System.out.print(rs.getString(j) + "\t");
                }
                System.out.println("");
            }

            // close (server) resource as soon as we are done processing resultset data
            rs.close();
            rs = null;

            // tell the driver to only return 5 rows for the next execution
            // it can optimize on this value, and will not fetch any more than 5 rows.
            st.setMaxRows(5);

            // we ask the database for 22 rows, while we set the JDBC driver to
            // 5 rows, this shouldn't be a problem at all...
            rs = st.executeQuery("select * from a limit 22");
            int var1_cnr = rs.findColumn("var1");
            int var2_cnr = rs.findColumn("var2");
            int var3_cnr = rs.findColumn("var3");
            int var4_cnr = rs.findColumn("var4");

            // read till the driver says there are no rows left
            for (int i = 0; rs.next(); i++) {
                System.out.println(
                    "[" + rs.getString(var1_cnr) + "]" +
                    "[" + rs.getString(var2_cnr) + "]" +
                    "[" + rs.getInt(var3_cnr) + "]" +
                    "[" + rs.getString(var4_cnr) + "]" );
            }

            // close (server) resource as soon as we are done processing resultset data
            rs.close();
            rs = null;

            // unset the row limit; 0 means as much as the database sends us
            st.setMaxRows(0);

            // we only ask 10 rows
            rs = st.executeQuery("select * from b limit 10;");
            int rowid_cnr = rs.findColumn("rowid");
            int id_cnr = rs.findColumn("id");
            var1_cnr = rs.findColumn("var1");
            var2_cnr = rs.findColumn("var2");
            var3_cnr = rs.findColumn("var3");
            var4_cnr = rs.findColumn("var4");

            // and simply print them
            while (rs.next()) {
                System.out.println(
                    rs.getInt(rowid_cnr) + ", " +
                    rs.getString(id_cnr) + ", " +
                    rs.getInt(var1_cnr) + ", " +
                    rs.getInt(var2_cnr) + ", " +
                    rs.getString(var3_cnr) + ", " +
                    rs.getString(var4_cnr) );
            }

            // close (server) resource as soon as we are done processing resultset data
            rs.close();
            rs = null;

            // perform a ResultSet-less query (with no trailing ; since that should
            // be possible as well and is JDBC standard)
            int updCount = st.executeUpdate("delete from a where var1 = 'zzzz'");
            System.out.println("executeUpdate() returned: " + updCount);

        } catch (SQLException se) {
            System.out.println(se.getMessage());
        } finally {
            // when done, close all (server) resources
            if (rs != null) rs.close();
            if (st != null) st.close();
            if (con != null) con.close();
        }
    }
}