/* Simple example how to connect to the local database (i.e., running on
 * the same machine to test JDBC. While this class could be generalized
 * it is intended to run with the stock Oracle 8.1.7.0.1. 
 * It is assumed that ORACLE_HOME, JAVA_HOME, CLASSPATH, and PATH are
 * are set to correct values. In this case the JDK 1.1.8 was used. 
 * This example uses the training database which comes with the Oracle.
 * This database has a user SCOTT with password TIGER by default.
 *
 * The program can be run like:
 *
 *  # include Oracle JDBC classes and current dir
 * CLASSPATH=${CLASSPATH}:${ORACLE_HOME}/jdbc/lib/classes111_g.zip:.
 * export CLASSPATH
 *
 *  # compile current program
 * javac JDBCTest.java
 *
 *  # Those are really set to make commend line parameters easy to see
 * ARG_DRIVER="oracle.jdbc.driver.OracleDriver"      #arg[0]
 * ARG_DB_URL="jdbc:oracle:oci8:@"                   #arg[1]
 * ARG_USER="scott"                                  #arg[2]
 * ARG_PASSWORD="tiger"                              #arg[3]
 *
 *  java JDBCTest $ARG_DRIVER $ARG_DB_URL $ARG_USER $ARG_PASSWORD 
 *
 *
 */


import java.sql.*;
import java.util.*;

public class JDBCTest {
  static public void main(String args[]) {
    Connection dbconnection = null;

    if(args.length != 4) {
      System.out.println("Usage: java JDBCTest DRIVER URL USER PASSWORD");
      return;
    }
    try {
      Class.forName(args[0]).newInstance();  // load the Driver
    }
    catch ( Exception e ) {
      System.err.println("We died at place A");
      e.printStackTrace();
      return;
    }                          
    try {                                   // Print arguments 
      for (int i=0; i < 4; i++) {
        System.out.println("Arg["+i+"]="+args[i]);
      }
      // connect to the database
      dbconnection = DriverManager.getConnection(args[1], args[2], args[3]);
      System.out.println("Connected to "+args[1]+" as user "+args[2]);
      Statement s = null;
      ResultSet r = null;
      s = dbconnection.createStatement();    // prepare for statement
      r=s.executeQuery(                      // execue Query
               "select ENAME from EMP where SAL < 2000");
      System.out.println("Results of the query:");
      System.out.println("select ENAME from EMP where SAL < 2000");

      while (r.next()) {                   // retrieve members of the ResultSet
        System.out.println(r.getString(1));
      }
    }
    catch (SQLException e) {
      System.err.println("We died at place B");
      throw new RuntimeException("SQL Exception " + e.getMessage());
    }
    finally {
      if( dbconnection != null ) {  // close connection if open
        try {
          dbconnection.close();
          System.out.println("Database connection closed");
        }
        catch ( SQLException e ) {
          System.err.println("We died at place C");
          e.printStackTrace();
        }
      }
    }
  }
}