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I actually new in asp.net c# I want to know why this code below doesn't work.
All I want to do is store data form into a SQL Server database.
I have 2 tables and I want the data form entered stored in the database. Look at the select statement for retrieving the primary key to store it as a foreign key in the other table
String q = "Insert into dbo.requests(request_date,request_type,visit_date,reason,user_id,status_id)values('" + DateTime.Now.ToString() + "','" + DropDownList1.SelectedValue.ToString() + "','" + TextBox8.Text.ToString() + "','" + TextBox9.Text.ToString() + "','"+ 1+"','"+ 2+"')";
SqlCommand cmd = new SqlCommand(q, con);
cmd.ExecuteNonQuery();
con.Close();
con2.Open();
if (con2.State == System.Data.ConnectionState.Open)
{
String a = "select top 1 request_id from dbo.requests where request_date= CAST(GETDATE() AS DATE and user_id=999 order by request_id DESC ";
SqlCommand cmd2 = new SqlCommand(a, con2);
int r = cmd2.ExecuteNonQuery();
}
con2.Close();
con3.Open();
if (con3.State == System.Data.ConnectionState.Open)
{
String b = "INSERT into dbo.visitor(visitor_Fname,visitor_Mname,visitor_family_name,visitor_id,visitor_mobile,request_id,place_of_work,country_name) values ('" + TextBox1.Text.ToString() + "','" + TextBox2.Text.ToString() + "','" + TextBox3.Text.ToString() + "','" + TextBox4.Text.ToString() + "' , '" + TextBox5.Text.ToString() + "','r', '" + TextBox6.Text.ToString() + "', '" + TextBox7.Text.ToString() + "' )";
SqlCommand cmd3 = new SqlCommand(b, con3);
cmd3.ExecuteNonQuery();
}
You should change it
int r = cmd2.ExecuteNonQuery();
to
int r = (int)cmd2.ExecuteScalar();
To retrieve selecting only one field use ExecuteScalar instead of ExecuteNonQuery. ExecuteNonQuery doesn't return selecting fields.
Just store request_id in variable using data table.
Actually you are storing 'r' in table which is wrong. Try to store request_id from select statement in variable it will be work .
I wrote a SQL command to save some items in my database. But when I run it, it gives an error message:
And here is my code:
public void Opslaan(string titel, string rVoornaam, string rAchternaam, decimal beoordeling, string a1Voornaam, string a1Achternaam, string a2Voornaam, string a2Achternaam, string a3Voornaam, string a3Achternaam)
{
if (beoordelingBest < beoordeling)
{
titelBest = titel;
beoordelingBest = beoordeling;
}
string queryString = "INSERT INTO Films (titel, beoordeling) VALUES('" + titel + "', " + beoordeling + ");" +
"INSERT INTO Acteurs (voornaam, achternaam, FilmID) VALUES('" + a1Voornaam + "' , '" + a1Achternaam + "', (SELECT FilmID from Films where titel = '" + titel + "'));" +
"INSERT INTO Acteurs (voornaam, achternaam, FilmID) VALUES('" + a2Voornaam + "' , '" + a2Achternaam + "', (SELECT FilmID from Films where titel = '" + titel + "'));" +
"INSERT INTO Acteurs (voornaam, achternaam, FilmID) VALUES('" + a3Voornaam + "' , '" + a3Achternaam + "', (SELECT FilmID from Films where titel = '" + titel + "'));" +
"INSERT INTO Regisseurs (voornaam, achternaam, FilmID) VALUES('" + rVoornaam + "' , '" + rAchternaam + "', (SELECT FilmID from Films where titel = '" + titel + "'));";
command = new SqlCommand(queryString, con);
Can someone please help me with this? I can't figure it out.
Use parametererized queries and do not use string concatination. This is to prevent sql injection attacks but also errors with the values like forgetting to make sure strins are escaped (if a string contains a ' for example).
If you have multiple queries each unique parameter value should have its own parameter name/value
Wrap your ado.net database types (SqlConnection, SqlCommand, etc) in using blocks if they are disposable
Never reuse connections as global objects, create, use, and destroy them when needed.
Here is the updated code with 1 statement, you can append additional statements to this and add more parameters as necessary.
var query = "INSERT INTO Acteurs (voornaam, achternaam, FilmID) SELECT #a1Voornaam, #a1Achternaam, FilmID from Films WHERE titel = #title";
using(var con = new SqlConnection("connection string here"))
using(var command = new SqlCommand(queryString, con))
{
command.Parameters.Add(new SqlParameter("#a1Voornaam", SqlDbType.VarChar){Value = a1Voornaam});
command.Parameters.Add(new SqlParameter("#achternaam", SqlDbType.VarChar){Value = achternaam});
command.Parameters.Add(new SqlParameter("#title", SqlDbType.VarChar){Value = title});
con.Open();
command.ExecuteNonQuery();
}
Perhaps one of your values is ');
That would terminate the INSERT statement early, and cause the error.
|
V
INSERT INTO Films (titel, beoordeling) VALUES('');,'anything');
You should use SqlParameters instead of string concatenation.
Are you using TextBoxes? I can't tell for sure. Try something like this, and change to suit your specific needs.
using System.Data.SqlClient;
protected void Button1_Click(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection(System.Configuration.
ConfigurationManager.ConnectionStrings["con"].ToString());
try
{
string query = "insert into UserDetail(Name,Address)
values('" + txtName.Text + "','" + txtAddress.Text + "');";
SqlDataAdapter da = new SqlDataAdapter(query, con);
con.Open();
da.SelectCommand.ExecuteNonQuery();
con.Close();
lblmessage.Text = "Data saved successfully.";
}
catch
{
con.Close();
lblmessage.Text = "Error while saving data.";
}
}
I need to get the userid(primary key auto_increment) from another table(login) into userdetails table. When trying to run it I keep getting this error " incorrect integer value: 'LAST_INSERT_ID()' for column 'userid' at row 1".
I've tried to take LAST_INSERT_ID() out and run another query after query4 to insert the value into the userid but I can't get it to insert into the right row it just opens a new row.
this is the code am trying to run.
try
{
//This is my connection string i have assigned the database file address path
string MyConnection2 = "datasource=localhost;port=3310;database=e-votingsystem;username=root;password=Password12;";
//this is my insert query in which i am taking input from the user through windows forms
string Query2 = "INSERT INTO vote (username) VALUE ('" + usernameInputBox.Text + "');";
string Query3 = "INSERT INTO login (username,upassword) VALUE ('" + usernameInputBox.Text + "','" + passwordInputBox.Text + "');";
string Query4 = "INSERT INTO userdetails (nationalinsurance,userid,forename,middlename,surname,housenumber,street,towncity,postcode,suffix) VALUES ('" + nationalInsuranceInputBox.Text + "','"+"LAST_INSERT_ID()"+"','" + forenameInputBox.Text + "','" + middleNameInputBox.Text + "','" + surnameInputBox.Text + "','" + houseNumberInputBox.Text + "','" + streetTextBox.Text + "','" + towncityTextBox.Text + "','" + postcodeInputBox.Text + "','" + suffixComboBox.Text+"');";
//This is MySqlConnection here i have created the object and pass my connection string.
MySqlConnection MyConn2 = new MySqlConnection(MyConnection2);
//This is command class which will handle the query and connection object.
MySqlCommand MyCommand2 = new MySqlCommand(Query2, MyConn2);
MySqlCommand MyCommand3 = new MySqlCommand(Query3, MyConn2);
MySqlCommand MyCommand4 = new MySqlCommand(Query4, MyConn2);
MySqlDataReader MyReader2;
MySqlDataReader MyReader3;
MySqlDataReader MyReader4;
// opens new connection to database then executes command
MyConn2.Open();
MyReader2 = MyCommand2.ExecuteReader(); // Here the query will be executed and data saved into the database.
while (MyReader2.Read())
{
}
MyConn2.Close();
// opens new connection to database then executes command
MyConn2.Open();
MyReader3 = MyCommand3.ExecuteReader();
while (MyReader3.Read())
{
}
MyConn2.Close();
//opens new connection to database the exexcutes command
MyConn2.Open();
MyReader4 = MyCommand4.ExecuteReader();
while (MyReader4.Read())
{
}
MyConn2.Close();
}
catch(Exception ex)
{
MessageBox.Show(ex.Message);
}
MessageBox.Show("Hello " + forename + surname, "read and accept the terms and conditions to continue");
//new termsAndConditionsPage().Show();
//Hide();
}
As explained in other answer, you have the LAST_INSERT_ID between single quotes and this transform it in a literal string not in a statement to execute. However also removing the quotes I am not sure that you can retrieve the LAST_INSERT_ID using a connection different from the one that originates the AUTOINCREMENT number on the login table. In any case you should use a different approach and, as a first thing, you should remove ASAP the string concatenations and use parameters (Reason: Sql Injection or SurName = O'Neill)
string Query2 = "INSERT INTO vote (username) VALUE (#uname)";
string Query3 = #"INSERT INTO login (username,upassword) VALUE (#uname, #upass);
SELECT LAST_INSERT_ID();";
string Query4 = #"INSERT INTO userdetails
(nationalinsurance,userid,forename,middlename,
surname,housenumber,street,towncity,postcode,suffix)
VALUES (#insurance, #userid, #forename, #middlename,
#surname, #housenum, #street, #town, #postcode, #suffix)";
Now open just one connection and build three commands, all between an using statement
using(MySqlConnection con = new MySqlConnection(.....constring here....))
using(MySqlCommand cmd2 = new MySqlCommand(Query2, con))
using(MySqlCommand cmd3 = new MySqlCommand(Query3, con))
using(MySqlCommand cmd4 = new MySqlCommand(Query4, con))
{
con.Open();
// Add the parameter to the first command
cmd2.Parameters.Add("#uname", MySqlDbType.VarChar).Value = usernameInputBox.Text;
// run the first command
cmd2.ExecuteNonQuery();
// Add parameters to the second command
cmd3.Parameters.Add("#uname", MySqlDbType.VarChar).Value = usernameInputBox.Text;
cmd3.Parameters.Add("#upass", MySqlDbType.VarChar).Value = passwordInputBox.Text;
// Run the second command, but this one
// contains two statement, the first inserts, the
// second returns the LAST_INSERT_ID on that table, we need to
// catch that single return
int userID = (int)cmd3.ExecuteScalar();
// Run the third command
// but first prepare the parameters
cmd4.Parameters.Add("#insurance", MySqlDbType.VarChar).Value = nationalInsuranceInputBox.Text;
cmd4.Parameters.Add("#userid", MySqlDbType.Int32).Value = userID;
.... and so on for all other parameters
.... using the appropriate MySqlDbType for the column type
cmd4.ExecuteNonQuery();
}
you current query has an error
string Query4 = "INSERT INTO userdetails (nationalinsurance,userid,forename,middlename,surname,housenumber,street,towncity,postcode,suffix) VALUE ('" + nationalInsuranceInputBox.Text + "','"+"LAST_INSERT_ID()"+"','" + forenameInputBox.Text + "','" + middleNameInputBox.Text + "','" + surnameInputBox.Text + "','" + houseNumberInputBox.Text + "','" + streetTextBox.Text + "','" + towncityTextBox.Text + "','" + postcodeInputBox.Text + "','" + suffixComboBox.Text + "');SELECT LAST_INSERT_ID();"
try the attached query
In your text query string you have: "','"+"LAST_INSERT_ID()"+"','". Note that the "','"s before and after the "LAST_INSERT_ID()" are incorrectly enclosing the LAST_INSERT_ID() term in single quotes.
Try the following query:
string Query4 = "INSERT INTO userdetails (nationalinsurance,userid,forename,middlename,surname,housenumber,street,towncity,postcode,suffix) VALUE ('" + nationalInsuranceInputBox.Text + "',"+"LAST_INSERT_ID()"+",'" + forenameInputBox.Text + "','" + middleNameInputBox.Text + "','" + surnameInputBox.Text + "','" + houseNumberInputBox.Text + "','" + streetTextBox.Text + "','" + towncityTextBox.Text + "','" + postcodeInputBox.Text + "','" + suffixComboBox.Text + "');";
I am new to the C# programming. Facing the problem Incorrect syntax near 'First_Name'.! in the given below code:
private void button2_Click(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection();
con.ConnectionString = #"Data Source=HP\SQLEXPRESS100;Database=CD_Gallery;Integrated Security=true";
con.Open();
if (con.State == System.Data.ConnectionState.Open)
{
SqlCommand cmd = new SqlCommand("update Customer_Info First_Name ='" + fname.Text + "'");
//'" + fname.Text.ToString() + "','" + lname.Text.ToString() + "','" + landmark.Text.ToString() + "','" + address.Text.ToString() + "','" + contact.Text.ToString() + "','" + email.Text.ToString() + "','" + dateTimePicker1.Text.ToString() + "','" + deposite.Text.ToString() + "')", con);
cmd.Connection = con;
cmd.CommandType = System.Data.CommandType.Text;
int a = cmd.ExecuteNonQuery();
if (a > 0)
{
MessageBox.Show("You Have Successfully Updated");
Custid.Text = "";
fname.Text = "";
lname.Text = "";
address.Text = "";
contact.Text = "";
email.Text = "";
landmark.Text = "";
deposite.Text = "";
}
}
}
Problem : You forgot to add word SET after your table name in update statement.
Solution1 : Add the word SET after table name in Update query (Don't Recommend this)
"update Customer_Info SET First_Name ='" + fname.Text + "'"
Warning : Your query is open to sql injection attacks.please use parameterised queries to avoid them
Solution 2: Using Parameterised Queries
Replace This:
SqlCommand cmd = new SqlCommand("update Customer_Info SET First_Name
='"+fname.Text+"'");
With This:
SqlCommand cmd = new SqlCommand("update Customer_Info First_Name = #fname");
cmd.Parameters.AddWithValue("#fname" , fname.Text);
Your problem not in C#, in SQL syntax (you miss set keyword)
SqlCommand("update Customer_Info set First_Name ='" + fname.Text + "'");
you are missing SET keyword:
update Customer_Info SET First_Name ='" + fname.Text + "'"
and also provide where clause otherwise it will update all the records in your table.
You are missing set keyword in query you have to place set like this
SqlCommand cmd = new SqlCommand("update Customer_Info set First_Name ='" + fname.Text + "'");
I've managed to run this query using wamp.
INSERT INTO guest (guestno,familyname)
VALUES(NULL,'Damn');
INSERT INTO reservation (reservationno, guestno)
VALUES(NUll,LAST_INSERT_ID())
However If I separately execute these 2 insert statements I will have a foreign key constraint.
I think the both of them need to be executed at the same time.
My questions are:
How to incorporate this into my c# winform code?
Is it possible to have 2 insert statements on one button?
When the user presses "add reservation" I would like the two MySQl query's to be executed.
Here's my insert statement:
private void button7_Click(object sender, EventArgs e)
{
string connectionString =
"Server=localhost;" +
"Database=sad;" +
"User ID=root;" +
"Password=root;" +
"Pooling=false";
IDbConnection dbcon;
dbcon = new MySqlConnection(connectionString);
dbcon.Open();
IDbCommand dbcmd = dbcon.CreateCommand();
string sql = "<insert statement>";
dbcmd.CommandText = sql;
IDataReader reader = dbcmd.ExecuteReader();
reader.Read();
}
UPDATED VERSION (DOESN'T WORK)
string connectionString =
"Server=localhost;" +
"Database=sad;" +
"User ID=root;" +
"Password=root;" +
"Pooling=false";
Form3 f3 = new Form3();
IDbConnection dbcon;
dbcon = new MySqlConnection(connectionString);
dbcon.Open();
IDbCommand dbcmd = dbcon.CreateCommand();
string sql = "insert into guest (guestno, familyname) values (null, '" + textBox6.Text + "'); insert into reservation (reservationno, guestno) values (null, LAST_INSERT_ID())";
dbcmd.CommandText = sql;
IDataReader reader = dbcmd.ExecuteReader();
reader.Read();
MessageBox.Show("Added Guest Reservation Successfully");
f3.guestList();
f3.reservationList();
Updated No.3 (STILL DOESN'T WORK)
string connectionString =
"Server=localhost;" +
"Database=sad;" +
"User ID=root;" +
"Password=root;" +
"Pooling=false";
IDbConnection dbcon;
dbcon = new MySqlConnection(connectionString);
dbcon.Open();
IDbCommand dbcmd = dbcon.CreateCommand();
dbcmd = new MySqlCommand("CreateGuestAndReservation", dbcon);
dbcmd.CommandType = CommandType.StoredProcedure;
dbcmd.Parameters.AddWithValue("familyName", "foo");
dbcmd.ExecuteNonQuery();
enter code here
You can't execute more than one statement on a given MySqlCommand.
Your best bet all around (maintainability, performance, readability) is to:
create a MySQL stored procedure for your 2 SQL statements.
call your stored proc using ExecuteNonQuery().
DELIMITER //
CREATE PROCEDURE CreateGuestAndReservation
(
IN familyName VARCHAR(255)
)
BEGIN
insert into guest (guestno, familyname)
values (null, familyName);
insert into reservation (reservationno, guestno)
values (null, LAST_INSERT_ID());
END//
DELIMITER ;
Call it from your WinForms code like this:
dbcon.Open();
cmd = new MySqlCommand("CreateGuestAndReservation", dbcon);
cmd.CommandType = CommandType.StoredProcedure;
//cmd.Parameters.AddWithValue("?familyName", "foo");
cmd.Parameters.Add("?familyName", MySqlDbType.VarChar,255).Value = "foo";
cmd.ExecuteNonQuery();
The code below should work but I suspect you may have already tried it given that you are asking for help?
string sql = "INSERT INTO guest (guestno,familyname) VALUES(NULL,'Damn'); INSERT INTO reservation (reservationno, guestno) VALUES(NUll,LAST_INSERT_ID())";
If you need parameters, try this:
string sql = "INSERT INTO guest (guestno,familyname) VALUES(NULL,?familyName); INSERT INTO reservation (reservationno, guestno) VALUES(NUll,LAST_INSERT_ID())";
...
dbcmd.Parameters.Add("#familyName", MySqlDbType.VarChar, 80).Value = _familyName;
EDIT: You may need to run 2 insert commands. See here.
I would suggest having a way to get ids other than relying on automatic id generation like autoincrements of mysql and sql server, which are very limiting. If you use a HILO id generator you first obtain id, and then execute a couple of inserts in a single transaction no problem, since you know your parent id beforehand.
It will not solve your immediate problem, but it will help tremendeously in future with your application, especially if storing parent-children like data is going to occur often.
Try this, it will work:
private void button56_Click(object sender, EventArgs e) {
con.Open();
SqlCommand cmd = new SqlCommand("insert into stholidays values('" + dateTimePicker12.Text + "','" + dateTimePicker20.Text + "','" + dateTimePicker13.Text + "','" + mbk + "','" + dateTimePicker14.Text + "','" + dateTimePicker15.Text + "','" + lt + "','" + dateTimePicker16.Text + "','" + dateTimePicker17.Text + "','" + ebk + "','" + dateTimePicker18.Text + "','" + dateTimePicker19.Text + "','" + textBox105.Text + "','" + textBox106.Text + "','" + textBox107.Text + "','" + dd + "','" + textBox104.Text + "')", con);
SqlCommand cmd1 = new SqlCommand("insert into holidays values('" + dd + "','" + ms + "','" + day + "','" + textBox104.Text + "')", con);
cmd.ExecuteNonQuery();
cmd1.ExecuteNonQuery();
con.Close();
}