Need help here,
i need to get the title into the comboboxes named cntpaginaBX and prmopaginaBX.
with one it works but when i try both .. It fails.
What i want to know is the "MySqlCommand".
how do i fix it because it doesnt take content, promo, sqlConn togheter.
MySqlConnection sqlConn = new MySqlConnection("Database=joshua;
Data Source=localhost; User Id='root'; Password=''");
string content = "SELECT title FROM content";
string promo = "SELECT title FROM promo";
MySqlCommand myCommando = new MySqlCommand(content, promo, sqlConn); <-----here
MySqlDataReader sqlReader;
object cont;
object prom;
try
{
sqlConn.Open();
sqlReader = myCommando.ExecuteReader();
while (sqlReader.Read())
{
cont = sqlReader.GetValue(0).ToString();
cntpaginaBX.Items.Add(cont);
prom = sqlReader.GetValue(0).ToString();
prmopaginaBX.Items.Add(prom);
}
sqlReader.Close();
}
catch (Exception x)
{
MessageBox.Show(x.Message, "Fout", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
finally
{
sqlConn.Close();
}
A MySqlCommand is used to run a single query. You cannot simply run two queries together. Each query needs to be a completely separate MySqlCommand.
string content = "SELECT title FROM content";
MySqlCommand contentCommand = new MySqlCommand(content, sqlConn);
try
{
sqlConn.Open();
sqlReader = contentCommand.ExecuteReader();
while (sqlReader.Read())
{
cont = sqlReader.GetValue(0).ToString();
cntpaginaBX.Items.Add(cont);
}
sqlReader.Close();
}
And then:
string promo = "SELECT title FROM promo";
MySqlCommand promoCommand = new MySqlCommand(promo, sqlConn);
try
{
sqlConn.Open();
sqlReader = promoCommand.ExecuteReader();
while (sqlReader.Read())
{
prom = sqlReader.GetValue(0).ToString();
prmopaginaBX.Items.Add(prom);
}
sqlReader.Close();
}
Related
I'm having a trouble with my code.
I'm trying to have the user the ability to submit his email to subscribe to my "notify me" service, I havn't code anything lately so I a bit confused..
I'm trying to Insert, Read, and Update data in my Online SQL Server.. but nothing seems to work! I don't know why I tried everything I know I check a million times it seems good.
Plus if there is any errors my catch should show it to me but even that doesn't work :(
Take a look at this maybe your eyes will see something I don't see.
protected void btnSubmit_Click(object sender, EventArgs e)
{
string cs = ConfigurationManager.ConnectionStrings["notifyCS"].ConnectionString;
using (SqlConnection conn = new SqlConnection(cs))
{
conn.Open();
try
{
string checkEmail = "SELECT User_Email FROM tbl_users WHERE User_Email = #User_Email";
string checkSubscription = "SELECT User_Status FROM tbl_users WHERE User_Email = #User_Email";
string submitEmail = "INSERT INTO tbl_users (User_UID, User_Email, User_Status) VALUES (#User_UID, #User_Email, #User_Status)";
string submitEmail2 = "UPDATE tbl_users SET User_UID = #User_UID, User_Status = #User_Status WHERE User_Email = #User_Email";
SqlCommand emailCMD = new SqlCommand(checkEmail, conn);
SqlDataAdapter emailSDA = new SqlDataAdapter
{
SelectCommand = emailCMD
};
DataSet emailDS = new DataSet();
emailSDA.Fill(emailDS);
//if there is no email registered.
if (emailDS.Tables[0].Rows.Count == 0)
{
SqlCommand registerEmail = new SqlCommand(submitEmail, conn);
string User_UID = System.Guid.NewGuid().ToString().Replace("-", "").ToUpper();
registerEmail.Parameters.AddWithValue("#User_UID", HttpUtility.HtmlEncode(User_UID));
registerEmail.Parameters.AddWithValue("#User_Email", HttpUtility.HtmlEncode(email.Text));
registerEmail.Parameters.AddWithValue("#User_Status", HttpUtility.HtmlEncode("subscribed"));
registerEmail.ExecuteNonQuery();
registerEmail.Dispose();
conn.Close();
conn.Dispose();
email.Text = null;
}
else if (emailDS.Tables[0].Rows.Count > 0)
{
using (SqlCommand checkSub = new SqlCommand(checkSubscription, conn))
{
checkSub.Parameters.AddWithValue("#User_Email", HttpUtility.HtmlEncode(email.Text));
SqlDataReader sdr = checkSub.ExecuteReader();
if (sdr.HasRows)
{
string res = sdr["User_Status"].ToString();
if (res != "subscribed")
{
using (SqlCommand registerEmail2 = new SqlCommand(submitEmail2, conn))
{
string User_UID = System.Guid.NewGuid().ToString().Replace("-", "").ToUpper();
registerEmail2.Parameters.AddWithValue("#User_UID", HttpUtility.HtmlEncode(User_UID));
registerEmail2.Parameters.AddWithValue("#User_Email", HttpUtility.HtmlEncode(email.Text));
registerEmail2.Parameters.AddWithValue("#User_Status", HttpUtility.HtmlEncode("subscribed"));
registerEmail2.ExecuteNonQuery();
registerEmail2.Dispose();
conn.Close();
conn.Dispose();
email.Text = null;
}
}
else
{
conn.Close();
conn.Dispose();
Response.Redirect("index.aspx");
}
}
}
}
}
catch (Exception ex)
{
Response.Write(ex.Message);
}
finally
{
conn.Close();
if (conn.State != ConnectionState.Closed)
{
conn.Close();
conn.Dispose();
}
}
}
}
Try it this way:
using (SqlConnection conn = new SqlConnection(cs))
{
conn.Open();
string checkEmail = "SELECT * FROM tbl_users WHERE User_Email = #User";
SqlCommand emailCMD = new SqlCommand(checkEmail, conn);
emailCMD.Parameters.Add("#User", SqlDbType.NVarChar).Value = email.Text;
SqlDataAdapter da = new SqlDataAdapter(emailCMD);
SqlCommandBuilder daU = new SqlCommandBuilder(da);
DataTable emailRecs = new DataTable();
emailRecs.Load(emailCMD.ExecuteReader());
DataRow OneRec;
if (emailRecs.Rows.Count == 0)
{
OneRec = emailRecs.NewRow();
emailRecs.Rows.Add(OneRec);
}
else
{
// record exists
OneRec = emailRecs.Rows[0];
}
// modify reocrd
OneRec["User_UID"] = User_UID;
OneRec["User_Email"] = email.Text;
OneRec["User_Status"] = "subscribed";
email.Text = null;
da.Update(emailRecs);
}
}
I'm using C# console app to update a table with a lot of rows based on the value of two column inside MySQL.
Below is the code that I've tried to update the table.
Is it possible to execute update during dataread while loop or do I need to use other way to accomplish this?
int currentPoints;
int shudhavePoints;
string email;
MySqlConnection con = new MySqlConnection(ConfigurationManager.ConnectionStrings["MySQLConnectionString"].ConnectionString);
con.Open();
MySqlCommand cmd1 = new MySqlCommand("SELECT user_email, meta_value AS 'Current Points', point FROM wp_usermeta", con);
MySqlDataReader rdr = null;
rdr = cmd1.ExecuteReader();
if(rdr.HasRows)
{
while(rdr.Read())
{
email = rdr.GetString(0);
currentPoints = Int32.Parse(rdr.GetString(1));
shudhavePoints = Int32.Parse(rdr.GetString(2));
if (currentPoints>shudhavePoints)
{
// I want to update here
MySqlCommand cmd2 = new MySqlCommand("UPDATE TABLE wp_usermeta SET meta_value = #cp WHERE user_email = #email", con);
cmd2.Parameters.AddWithValue("#cp", shudhavePoints);
cmd2.Parameters.AddWithValue("#email",email);
cmd2.ExecuteNonQuery();
}
}
Console.ReadLine();
}
else
{
Console.WriteLine("I read nothing!");
Console.ReadLine();
}
Right now if I execute the programs, the data will not be updated and will show error
'There is already an open DataReader associated with this Connection which must be closed first.'
However if I close the connection, it will only execute and update the very first row which satisfy the if-else rule.
I think there must be a way for this to run in a loop without having me to run the program repeating times.
Can anyone suggest how should I fix the code for that?
U can define new connection object for that
int currentPoints;
int shudhavePoints;
string email;
MySqlConnection con = new MySqlConnection(ConfigurationManager.ConnectionStrings["MySQLConnectionString"].Connection
String);
MySqlConnection con1 = new MySqlConnection(ConfigurationManager.ConnectionStrings["MySQLConnectionString"].Connection
String);
con.Open();
MySqlCommand cmd1 = new MySqlCommand("SELECT user_email, meta_value AS 'Current Points', point FROM wp_usermeta", con);
MySqlDataReader rdr = null;
rdr = cmd1.ExecuteReader();
if(rdr.HasRows)
{
while(rdr.Read())
{
email = rdr.GetString(0);
currentPoints = Int32.Parse(rdr.GetString(1));
shudhavePoints = Int32.Parse(rdr.GetString(2));
if (currentPoints>shudhavePoints)
{
// I want to update here
MySqlCommand cmd2 = new MySqlCommand("UPDATE TABLE wp_usermeta SET meta_value = #cp WHERE user_email = #email", con1);
cmd2.Parameters.AddWithValue("#cp", shudhavePoints);
cmd2.Parameters.AddWithValue("#email",email);
cmd2.ExecuteNonQuery();
}
}
Console.ReadLine();
}
else
{
Console.WriteLine("I read nothing!");
Console.ReadLine();
}
int currentPoints;
int shudhavePoints;
string email;
MySqlConnection con = new MySqlConnection(ConfigurationManager.ConnectionStrings["MySQLConnectionString"].ConnectionString);
con.Open();
MySqlCommand cmd1 = new MySqlCommand("SELECT user_email, meta_value AS 'Current Points', point FROM wp_usermeta", con);
MySqlDataReader rdr = null;
rdr = cmd1.ExecuteReader();
if(rdr.HasRows)
{
while(rdr.Read())
{
email = rdr.GetString(0);
currentPoints = Int32.Parse(rdr.GetString(1));
shudhavePoints = Int32.Parse(rdr.GetString(2));
if (currentPoints>shudhavePoints)
{
//I want to update here
MySqlCommand cmd2 = new MySqlCommand("UPDATE TABLE wp_usermeta SET meta_value = #cp WHERE user_email = #email", con);
cmd2.Parameters.AddWithValue("#cp", shudhavePoints);
cmd2.Parameters.AddWithValue("#email",email);
cmd2.ExecuteNonQuery();
}
if(!rdr.read())
{
Console.WriteLine("Update query not working!!!");
}
else
{
//user_email
string usermail = Convert.ToString(user_email);
usermail = rdr[0].ToString();
Console.WriteLine("Username: {0}", usermail.ToString());
//meta_value AS 'Current Points'
string metavalue = Convert.ToString(meta_value);
metavalue = rdr[1].ToString();
Console.WriteLine("metavalue: {0}", metavalue.ToString());
//meta_value AS 'point'
string points = Convert.ToString(point);
points = rdr[2].ToString();
Console.WriteLine("point: {0}", points.ToString());
Console.ReadLine();
}
}
Console.ReadLine();
}
else
{
Console.WriteLine("I read nothing!");
Console.ReadLine();
}
I am previously only familiar with Linq and the like for data access. I am working on something now that requires me to use actual SQL commands on the back end to return a single value. My code compiles and runs, however it is returning null for a value that I know should be returning something besides an empty string...
Is my structure off on this? Or is something else missing?
Below is my code:
internal string GetSexDescription(string sex, int id_merchant)
{
string newSex = "";
var builder = new ConnectionStringHelper();
var connString = builder.getCasinoDBString(id_merchant);
using (SqlConnection conn = new SqlConnection(connString))
{
string sql = "SELECT Description FROM person_gender_lookup WHERE ID = #sex";
SqlCommand cmd = new SqlCommand(sql, conn);
try
{
cmd.Parameters.Add("#Sex", SqlDbType.VarChar).Value = sex;
newSex = cmd.ExecuteScalar().ToString();
}
catch(Exception ex)
{
Console.WriteLine(ex.Message);
}
return newSex;
}
}
Here is a picture of the result set of the table:
Open the connection.
internal string GetSexDescription(string sex, int id_merchant)
{
string newSex = "";
var builder = new ConnectionStringHelper();
var connString = builder.getCasinoDBString(id_merchant);
using (SqlConnection conn = new SqlConnection(connString))
{
conn.Open(); //<- This line here.
string sql = "SELECT Description FROM person_gender_lookup WHERE ID = #sex";
SqlCommand cmd = new SqlCommand(sql, conn);
try
{
cmd.Parameters.Add("#Sex", SqlDbType.VarChar).Value = sex;
newSex = cmd.ExecuteScalar().ToString();
}
catch(Exception ex)
{
Console.WriteLine(ex.Message);
}
return newSex;
}
}
cmd.ExecuteScalar() is probably throwing an InvalidOperationException because you haven't opened the connection. The exception is being caught, outputted to the console, then the initial value of newSex is begin returned since the call to ExecuteScalar threw.
ID is a int or varchar?
If is int use:
cmd.Parameters.Add("#sex", SqlDbType.Int).Value = sex;
instead of:
cmd.Parameters.Add("#Sex", SqlDbType.VarChar).Value = sex;
P.S.
Query parameters and parameter add into cmd.Parameters is case sensitive.
Write
#sex
instead of
#Sex
Figured it out. Had to open the cmd and close it AFTER I set the newSex variable to the value being pulled.
internal string GetSexDescription(string sex, int id_merchant)
{
string newSex = "";
var builder = new ConnectionStringHelper();
var connString = builder.getCasinoDBString(id_merchant);
DataSet ds = new DataSet();
using (SqlDataAdapter adapter = new SqlDataAdapter())
{
using (SqlConnection conn = new SqlConnection(connString))
{
string sql = "SELECT Description FROM person_gender_lookup WHERE ID = #Sex";
SqlCommand cmd = new SqlCommand(sql, conn);
try
{
conn.Open();
cmd.Connection = conn;
adapter.SelectCommand = cmd;
cmd.Parameters.Add("#Sex", SqlDbType.VarChar).Value = sex;
adapter.Fill(ds);
newSex = cmd.ExecuteScalar().ToString();
conn.Close();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
return newSex;
}
}
}
Try this:
internal string GetSexDescription(string sex, int id_merchant)
{
string newSex = "";
var builder = new ConnectionStringHelper();
var connString = builder.getCasinoDBString(id_merchant);
using (SqlConnection conn = new SqlConnection(connString))
{
string sql = "SELECT Description FROM person_gender_lookup WHERE ID" + sex;;
SqlCommand cmd = new SqlCommand(sql, conn);
try
{
newSex = cmd.ExecuteScalar().ToString();
}
catch(Exception ex)
{
Console.WriteLine(ex.Message);
}
return newSex;
}
}
I tried the following in SQL Server Management Studio; I can connect and run query, but not from my project
string s = "Server=LAPTOP-7J47C5JA\SQLEXPRESS;Database=Test;Trusted_Connection=True;";
string queryString = "SELECT * from tbclienti";
cn = new SQLConnection(s);
// Create the Command and Parameter objects.
SqlCommand command = new SqlCommand(queryString, cn);
cn.Open();
SqlDataReader reader = command.ExecuteReader();
while (reader.Read())
{
Text = reader[0].ToString();
label1.Text = reader[1].ToString()+ " " + reader[2].ToString();
}
reader.Close();
cn.Close();
I posted here whole code what could look like. Try it now.
string s = #"Server=(local)\SQLEXPRESS;Database=Test;Integrated Security=SSPI;";
using(SqlConnection cn = new SqlConnection(s))
{
string queryString = "SELECT * from tbclienti";
try
{
cn.Open();
// Create the Command and Parameter objects.
SqlCommand command = new SqlCommand(queryString, cn);
SqlDataReader reader = command.ExecuteReader();
while (reader.Read())
{
Text = reader[0].ToString();
label1.Text = reader[1].ToString()+ " " + reader[2].ToString();
}
reader.Close();
}
catch(Exception ex)
{
// see if error appear
}
finally
{
cn.Close();
}
}
How do I go about setting a MySQL query and parameters based on a condition?
I want different queries based on 'questionSource' as shown below.
However, in my code below, 'cmd' does not exist in the current context.
Alternatively, I could have two different functions for each condition and call the necessary function as required but I imagine there must be a way to have conditions within a connection.
//validation checks
else
{
string connStr = ConfigurationManager.ConnectionStrings["myConnectionString"].ConnectionString;
MySqlConnection conn = new MySqlConnection(connStr);
string questionSource = Session["QuestionSource"].ToString();
string cmdText = "";
if (questionSource.Equals("S"))
{
cmdText += #"SELECT COUNT(*) FROM questions Q
JOIN users U
ON Q.author_id=U.user_id
WHERE approved='Y'
AND role=1
AND module_id=#ModuleID";
MySqlCommand cmd = new MySqlCommand(cmdText, conn);
cmd.Parameters.Add("#ModuleID", MySqlDbType.Int32);
cmd.Parameters["#ModuleID"].Value = Convert.ToInt32(Session["TestModuleID"]);
}
else if (questionSource.Equals("U"))
{
cmdText += "SELECT COUNT(*) FROM questions WHERE approved='Y' AND module_id=#ModuleID AND author_id=#AuthorID;";
MySqlCommand cmd = new MySqlCommand(cmdText, conn);
cmd.Parameters.Add("#ModuleID", MySqlDbType.Int32);
cmd.Parameters["#ModuleID"].Value = Convert.ToInt32(Session["TestModuleID"]);
cmd.Parameters.Add("#AuthorID", MySqlDbType.Int32);
cmd.Parameters["#AuthorID"].Value = Convert.ToInt32(Session["UserID"]);
}
int noOfQuestionsAvailable = 0;
int noOfQuestionsWanted = Convert.ToInt32(ddlNoOfQuestions.SelectedValue);
try
{
conn.Open();
noOfQuestionsAvailable = Convert.ToInt32(cmd.ExecuteScalar());
if (noOfQuestionsAvailable < noOfQuestionsWanted)
{
lblError.Text = "There are not enough questions available to create a test.";
}
else
{
Session["TestName"] = txtName.Text;
Session["NoOfQuestions"] = ddlNoOfQuestions.SelectedValue;
Session["QuestionSource"] = rblQuestionSource.SelectedValue;
Session["TestModuleID"] = ddlModules.SelectedValue;
Response.Redirect("~/create_test_b.aspx");
}
}
catch
{
lblError.Text = "Database connection error - failed to get module details.";
}
finally
{
conn.Close();
}
}
declare cmd before if
MySqlCommand cmd = new MySqlCommand("",connStr);
and in each part of if
cmd.CommandText=cmdText;
other suggestion: add
cmd.Parameters.Add("#ModuleID", MySqlDbType.Int32);
cmd.Parameters["#ModuleID"].Value = Convert.ToInt32(Session["TestModuleID"]);
always before if because it is used in the same way in if and else part
You just have to move the declaration of the cmd outside the if block:
//validation checks
else
{
string connStr = ConfigurationManager.ConnectionStrings["myConnectionString"].ConnectionString;
MySqlConnection conn = new MySqlConnection(connStr);
string questionSource = Session["QuestionSource"].ToString();
string cmdText = "";
MySqlCommand cmd; // <-- here
if (questionSource.Equals("S"))
{
cmdText += #"SELECT COUNT(*) FROM questions Q
JOIN users U
ON Q.author_id=U.user_id
WHERE approved='Y'
AND role=1
AND module_id=#ModuleID";
cmd = new MySqlCommand(cmdText, conn); // remove MySqlCommand here
cmd.Parameters.Add("#ModuleID", MySqlDbType.Int32);
cmd.Parameters["#ModuleID"].Value = Convert.ToInt32(Session["TestModuleID"]);
}
else if (questionSource.Equals("U"))
{
cmdText += "SELECT COUNT(*) FROM questions WHERE approved='Y' AND module_id=#ModuleID AND author_id=#AuthorID;";
cmd = new MySqlCommand(cmdText, conn); // remove MySqlCommand here
cmd.Parameters.Add("#ModuleID", MySqlDbType.Int32);
cmd.Parameters["#ModuleID"].Value = Convert.ToInt32(Session["TestModuleID"]);
cmd.Parameters.Add("#AuthorID", MySqlDbType.Int32);
cmd.Parameters["#AuthorID"].Value = Convert.ToInt32(Session["UserID"]);
}
int noOfQuestionsAvailable = 0;
int noOfQuestionsWanted = Convert.ToInt32(ddlNoOfQuestions.SelectedValue);
try
{
conn.Open();
noOfQuestionsAvailable = Convert.ToInt32(cmd.ExecuteScalar());
if (noOfQuestionsAvailable < noOfQuestionsWanted)
{
lblError.Text = "There are not enough questions available to create a test.";
}
else
{
Session["TestName"] = txtName.Text;
Session["NoOfQuestions"] = ddlNoOfQuestions.SelectedValue;
Session["QuestionSource"] = rblQuestionSource.SelectedValue;
Session["TestModuleID"] = ddlModules.SelectedValue;
Response.Redirect("~/create_test_b.aspx");
}
}
catch
{
lblError.Text = "Database connection error - failed to get module details.";
}
finally
{
conn.Close();
}
}
Just move the declaration of the MySqlCommand outside the if/else blocks so you could use it in the final try where you execute the command
//validation checks
else
{
string connStr = ConfigurationManager.ConnectionStrings["myConnectionString"].ConnectionString;
using(MySqlConnection conn = new MySqlConnection(connStr))
using(MySqlCommand cmd = conn.CreateCommand())
{
// Don't need to associate the command to the connection
// Already done by the CreateCommand above, just need to set
// the parameters and the command text
if (questionSource.Equals("S"))
{
cmdText = #"....."
cmd.CommandText = cmdText;
....
}
else if (questionSource.Equals("U"))
{
cmdText = "........."
cmd.CommandText = cmdText;
....
}
try
{
conn.Open();
noOfQuestionsAvailable = Convert.ToInt32(cmd.ExecuteScalar());
....
}
}
}
Notice also that you should use the using statement to be sure that your connection and your command are propertly closed and disposed.