import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;

public class PsqlLib157 {

    public Connection connection;
    public Statement statement;
    public ResultSet resultSet;
    public DatabaseMetaData databaseMetaData;
    public ResultSetMetaData resultSetMetaData;

    public String ip = "127.0.0.1";
    public String port = "5432";
    public String db = "media";
    public String passwd = "123123";
    public String acc = "postgres";
    public String url = "jdbc:postgresql://" +
                         ip + ":" + port + "/" + db;

    PsqlLib157() {

        try {
            //strang till classen for postgresql driver
            Class.forName("org.postgresql.Driver");

            //skapa anslutning till databasen
            connection = DriverManager.getConnection(url, acc, passwd);

            //hamta meta data efter anslutning ar skapad
            databaseMetaData = connection.getMetaData();

            statement = connection.createStatement();

        }
        catch (ClassNotFoundException e) {
            e.printStackTrace();
            System.exit(1);
        }
        catch (SQLException e) {
            e.printStackTrace();
            System.exit(2);
        }
    }

    public void execDDL(String querry) {
        try {statement.executeUpdate(querry);}
        catch(SQLException e) {e.printStackTrace();}
    }
    public ResultSet execDML(String querry) {
        try{resultSet = statement.executeQuery(querry);}
        catch(SQLException e) {e.printStackTrace();}
        return resultSet;
    }
    public String returnResult() {
        String columnName = "";
        int numberOfColumns;
        try {
            resultSetMetaData = resultSet.getMetaData();
            numberOfColumns = resultSetMetaData.getColumnCount();

              for (int i = 1; i <= numberOfColumns; i++) {
                  columnName += "[" +
                  resultSetMetaData.getColumnName(i) +
                  "], ";
              }
              columnName += "\n\n";

                while (resultSet.next()) {
                      for (int i = 1; i <= numberOfColumns; i++) {
                        columnName += resultSet.getString(i) + ", ";
                      }
                      columnName += "\n";
                }
        } catch (SQLException e) {e.printStackTrace();}
        return columnName;
    }
}