public XmlDocument DbToXml(string username)
{
XmlDocument doc = new XmlDocument();
Postgre conn = new Postgre();
string sql = "SELECT * FROM examresult WHERE username=:username";
try
{
conn._cmd = new NpgsqlCommand(sql, conn._conn);
conn._cmd.Parameters.AddWithValue("username", username);
conn._dr = conn._cmd.ExecuteReader();
while (conn._dr.Read())
{
doc.LoadXml(conn._dr["xml"].ToString());
}
return(doc);
}
catch (NpgsqlException e)
{
Debug.Write(e);
return(null);
}
finally
{
conn.CloseConnection();
}
}
public string GetQuestionFromDB(int question_id)
{
Postgre conn = new Postgre();
string sql = "SELECT * FROM exam WHERE question_id=:question_id";
try
{
conn._cmd = new NpgsqlCommand(sql, conn._conn);
conn._cmd.Parameters.AddWithValue("question_id", question_id);
conn._dr = conn._cmd.ExecuteReader();
while (conn._dr.Read())
{
question = conn._dr["question"] as string ?? "";
}
return(question);
}
catch (NpgsqlException e)
{
Debug.Write(e);
throw;
}
finally
{
conn.CloseConnection();
}
}
public List <string> GetAnswersFromDB(int question)
{
Postgre conn = new Postgre();
string sql = "SELECT * FROM answers WHERE question=:question";
List <string> answers = new List <string>();
string answer = null;
try
{
conn._cmd = new NpgsqlCommand(sql, conn._conn);
conn._cmd.Parameters.AddWithValue("question", question);
conn._dr = conn._cmd.ExecuteReader();
while (conn._dr.Read())
{
answer = conn._dr["answer"] as string ?? "";
answers.Add(answer);
}
return(answers);
}
catch (Exception e)
{
Debug.Write(e);
throw;
}
finally
{
conn.CloseConnection();
}
}
public string GetCorrectAnswerTemp(int question)
{
Postgre conn = new Postgre();
string sql = "select * from answers a where a.question = @question and a.correct = true";
try
{
conn._cmd = new NpgsqlCommand(sql, conn._conn);
conn._cmd.Parameters.AddWithValue("question", question);
conn._dr = conn._cmd.ExecuteReader();
while (conn._dr.Read())
{
answer = conn._dr["answer"] as string ?? "";
}
return(answer);
}
catch (Exception e)
{
Debug.Write(e);
throw;
}
finally
{
conn.CloseConnection();
}
}
public string GetCategory(int question_id)
{
Postgre conn = new Postgre();
string sql = "select * from exam where question_id = @question_id";
try
{
conn._cmd = new NpgsqlCommand(sql, conn._conn);
conn._cmd.Parameters.AddWithValue("question_id", question_id);
conn._dr = conn._cmd.ExecuteReader();
while (conn._dr.Read())
{
category = conn._dr["category"] as string ?? "";
}
return(category);
}
catch (Exception e)
{
Debug.Write(e);
throw;
}
finally
{
conn.CloseConnection();
}
}
public bool GetLicenseApproved(string username)
{
Postgre conn = new Postgre();
string sql = "select * from person where username = @username";
bool approved = false;
try
{
conn._cmd = new NpgsqlCommand(sql, conn._conn);
conn._cmd.Parameters.AddWithValue("username", username);
conn._dr = conn._cmd.ExecuteReader();
while (conn._dr.Read())
{
approved = conn._dr["licensed"] as bool? ?? default(bool);
}
return(approved);
}
catch (Exception e)
{
Debug.Write(e);
return(false);
}
finally
{
conn.CloseConnection();
}
}
public DataTable GetUserList()
{
Postgre db = new Postgre();
DataTable dt = new DataTable();
string sql = "SELECT * FROM person WHERE isadmin = false";
dt = db.Select(sql);
return(dt);
}
public DataTable GetExam(string user)
{
Postgre db = new Postgre();
DataTable dt = new DataTable();
// Dictionary to send parameters in format key-value
Dictionary <string, string> myParams = new Dictionary <string, string>();
myParams.Add("@uname", user);
string sql = "select distinct on (\"username\") * from examresult WHERE username = @uname ORDER BY username, date DESC";
dt = db.Select(sql, myParams);
return(dt);
}
public DataTable AdmLogin()
{
Postgre db = new Postgre();
DataTable dt = new DataTable();
Dictionary <string, string> myParams = new Dictionary <string, string>();
myParams.Add("@username", Username);
myParams.Add("@password", Password);
// Sql query with parameters
string sql = "SELECT * FROM person " +
"WHERE username = @username AND " +
"password = @password AND " +
"isadmin = true";
dt = db.Select(sql, myParams);
return(dt);
}
/// <summary>
/// Method to get all question IDs.
/// </summary>
/// <returns>List of all Question IDs</returns>
public List <int> GetQuestionIDs(int examType)
{
Postgre conn = new Postgre();
string sql = "";
if (examType == 1 || examType == null)
{
sql = "select question_id from exam order by random() limit 25";
}
else if (examType == 2)
{
sql = "select question_id from exam order by random() limit 15";
}
List <int> ids = new List <int>();
int id = 0;
try
{
conn._cmd = new NpgsqlCommand(sql, conn._conn);
conn._dr = conn._cmd.ExecuteReader();
while (conn._dr.Read())
{
id = conn._dr["question_id"] as int? ?? default(int);
ids.Add(id);
}
return(ids);
}
catch (Exception e)
{
Debug.Write(e);
throw;
}
finally
{
conn.CloseConnection();
}
}
public bool updateLicense(string username, bool licensed)
{
Postgre conn = new Postgre();
string sql = "UPDATE person SET licensed = @licensed WHERE username = @username";
try
{
conn._cmd = new NpgsqlCommand(sql, conn._conn);
conn._cmd.Parameters.Add(new NpgsqlParameter("licensed", licensed));
conn._cmd.Parameters.Add(new NpgsqlParameter("username", username));
if (conn._cmd.ExecuteNonQuery() == 1)
{
return(true);
}
return(false);
}
catch (NpgsqlException e)
{
Debug.Write(e);
return(false);
}
}
//public DataTable GetCorrectAnswer(string question)
//{
// //Postgre db = new Postgre();
// //DataTable dt = new DataTable();
// //// Dictionary to send parameters in format key-value
// //Dictionary<string, string> myParams = new Dictionary<string, string>();
// //myParams.Add("@question_id", question);
// //// Sql query with parameters
// //string sql = "select * from exam e, answers a where e.correct_answer = a.answer_id and question_id = '@question'";
// //dt = db.Select(sql, myParams);
// //return dt;
//}
public bool xmlToDb(string username, string xml, DateTime today)
{
Postgre conn = new Postgre();
string sql = "INSERT INTO examresult(username, xml, date) VALUES(@username, @xml, @today)";
try
{
conn._cmd = new NpgsqlCommand(sql, conn._conn);
conn._cmd.Parameters.Add(new NpgsqlParameter("xml", xml));
conn._cmd.Parameters.Add(new NpgsqlParameter("username", username));
conn._cmd.Parameters.Add(new NpgsqlParameter("today", today));
if (conn._cmd.ExecuteNonQuery() == 1)
{
return(true);
}
return(false);
}
catch (NpgsqlException e)
{
Debug.Write(e);
return(false);
}
}
