Hie.
So what I'm trying to do is insert a null value in an integer column in MySQL using a C# application.
I'm aware the query to generally do such a thing would be;
INSERT INTO Database.Table (IntColumn) VALUES (NULL);
UPDATE Database.Table set IntColumn = (NULL) where id = '1';
It works great in workbench. Thing is, I'm not even sure if this is possible but I need to do this in C# while still allowing the textbox the flexibility to enter integers into the MySQL database. In this case 'home.text' which is linked up to 'home' column in MySQL which is an integer field.
This is how I made my code.
using MySql.Data.MySqlClient;
using MySql.Data;
namespace Masca.Content
{
/// <summary>
/// Interaction logic for Login.xaml
/// </summary>
public partial class Login : UserControl
{
//Function to check if column value is null before fetching string
public static string GetString(MySqlDataReader reader, string colName)
{
if (reader[colName] == DBNull.Value)
return string.Empty;
else
return (string)reader[colName];
}
//Function to check if column value is null before fetching int as string
public static string GetColumnValueAsString(MySqlDataReader reader, string colName)
{
if (reader[colName] == DBNull.Value)
return string.Empty;
else
return reader[colName].ToString();
}
public Login()
{
InitializeComponent();
}
public void save_Click(object sender, RoutedEventArgs e)
{
//Authentication parameters
string sqlcon = "datasource = localhost; port = 3306; username = root; password = root";
//Query to excecute
string queryadd = "insert into users.employees (member, username, password, question, answer, first, second, third, surname, dob, gender, doc, dept, cell, home, work, email, pemail, street, surbub, city, region, position, access, privilages, bank, account) values ('" + this.member.Text + "','" + this.username.Text + "','" + this.password.Text + "', '" + this.question.Text + "','" + this.answer.Text + "', '" + this.first.Text + "','" + this.second.Text + "','" + this.third.Text + "','" + this.surname.Text + "', '" + this.dob.Text + "','" + this.gender.Text + "', '" + this.doc.Text + "', '" + this.dept.Text + "', '" + this.cell.Text + "','" + this.home.Text + "', '" + this.work.Text + "', '" + this.email.Text + "', '" + this.pemail.Text + "', '" + this.street.Text + "', '" + this.surbub.Text + "', '" + this.city.Text + "', '" + this.region.Text + "', '" + this.position.Text + "', '" + this.access.Text + "', '" + this.privilages.Text + "', '" + this.bank.Text + "', '" + this.account.Text + "') ; insert into logon.login (username, password) values ('" +this.username.Text+ "', '" +this.password.Text+ "'); select * from users.employees where member = '" + this.member.Text + "' ;";
MySqlConnection con = new MySqlConnection(sqlcon);
MySqlDataReader rdr;
MySqlCommand cmd = new MySqlCommand(queryadd, con);
// Excecution
try
{
con.Open();
rdr = cmd.ExecuteReader();
MessageBox.Show("Saved");
while (rdr.Read())
{
//Declarations using function
string stag = GetColumnValueAsString(rdr, "tag");
string snumber = GetColumnValueAsString(rdr, "tag");
string smember = GetColumnValueAsString(rdr, "member");
string susername = GetString(rdr, "username");
string spassword = GetString(rdr, "password");
string ssecurity = GetString(rdr, "question");
string sanswer = GetString(rdr, "answer");
string sfirst = GetString(rdr, "first");
string ssecond = GetString(rdr, "second");
string sthird = GetString(rdr, "third");
string sfourth = GetString(rdr, "surname");
string sdob = rdr.GetString("dob");
string sgender = rdr.GetString("gender");
string sdoc = rdr.GetString("doc");
string sdept = rdr.GetString("dept");
string scell = GetColumnValueAsString(rdr, "cell");
string shome = GetColumnValueAsString(rdr, "home");
string swork = GetColumnValueAsString(rdr, "work");
string semail = GetString(rdr, "email");
string spemail = GetString(rdr, "pemail");
string sstreet = GetString(rdr, "street");
string ssurbub = GetString(rdr, "surbub");
string scity = GetString(rdr, "city");
string sregion = GetString(rdr, "region");
string sposition = GetString(rdr, "position");
string saccess = GetString(rdr, "access");
string sprivilages = GetString(rdr, "privilages");
string sbank = GetString(rdr, "bank");
string saccount = GetString(rdr, "account");
//Binding strings to textboxes
tag.Text = stag;
number.Text = stag;
member.Text = smember;
username.Text = susername;
password.Text = spassword;
question.Text = ssecurity;
answer.Text = sanswer;
first.Text = sfirst;
second.Text = ssecond;
third.Text = sthird;
surname.Text = sfourth;
dob.Text = sdob;
gender.Text = sgender;
doc.Text = sdoc;
dept.Text = sdept;
cell.Text = scell;
home.Text = shome;
work.Text = swork;
email.Text = semail;
pemail.Text = spemail;
street.Text = sstreet;
surbub.Text = ssurbub;
city.Text = scity;
region.Text = sregion;
position.Text = sposition;
access.Text = saccess;
privilages.Text = sprivilages;
bank.Text = sbank;
account.Text = saccount;
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
This is the code behind a form that contains employee details. home.text is supposed to hold the home land line number. Assuming the employee doesn't have a land line at home, they would leave the field blank.
Everytime I do that however, I get an exception thrown saying "Incorrect integer value". To leave it blank in the database, I would have to type (NULL) where '"this.home.text'" currently is in the query. If i do that though, I wont be able to insert information into the database using home.text when need be.
Anyother way to do this?
Insert Usual preamble about your SQL being open to injection attacks (see this question for more information on parameterized SQL).
The problem is, you're inserting strings in to all the columns, irrespective of the underlying database type.
this:
'" + this.home.text + "'
If blank, will produce '', which cannot be converted to an integer. You might want to try something like:
int? homeNumber = null; // Note the int? is syntactic sugar for Nullable<int>
if(!string.IsNullOrEmpty(home.text))
homeNumber = Convert.ToInt32(home.Text);
And insert thusly:
," + homeNumber + ",.... etc.
You could try something along the lines of
if (!int.TryParse(shome, out home.Text))
home.Text = null;
I think instead you should just check for empty or null strings,
string queryadd = "insert into users.employees (member, username, password, question, answer, first, second, third, surname, dob, gender, doc, dept, cell, home, work, email, pemail, street, surbub, city, region, position, access, privilages, bank, account) values ('"
+ this.member.Text + "','" + this.username.Text + "','" + this.password.Text + "', '" + this.question.Text + "','" + this.answer.Text + "', '" + this.first.Text + "','" + this.second.Text + "','" + this.third.Text
+ "','" + this.surname.Text + "', '" + this.dob.Text + "','" + this.gender.Text + "', '" + this.doc.Text + "', '" + this.dept.Text + "', '" + this.cell.Text + "','"
+ string.IsNullOrWhiteSpace(this.home.Text) ? null : this.home.Text + "', '"
+ this.work.Text + "', '" + this.email.Text + "', '" + this.pemail.Text + "', '" + this.street.Text + "', '" + this.surbub.Text + "', '" + this.city.Text + "', '" + this.region.Text + "', '" + this.position.Text + "', '"
+ this.access.Text + "', '" + this.privilages.Text + "', '" + this.bank.Text + "', '" + this.account.Text
+ "') ; insert into logon.login (username, password) values ('" + this.username.Text + "', '" + this.password.Text + "'); "
+ " select * from users.employees where member = '" + this.member.Text + "' ;";
look at string.IsNullOrWhiteSpace(this.home.Text) ? null : this.home.Text
I don't think so the SQL that you have formed is right and will work like this, i.e. two SQL separated by ; and also has SELECT SQL merged with INSERT
Related
Data comes from "Temp" table.
Stored in variables
Inserted into "Client" table with the addition of two more variables.
And there comes an error. The INSERT query is not executing properly.
Query,
int r;
string que = "INSERT INTO client (fname, lname, dob,
email, gender, uname, upass) VALUES
('" + fname + "',
'" + lname + "', '" + dob + "',
'" + email + "',
'" + gender + "',
'" + TextBox1.Text + "',
'" + TextBox2.Text + "') ";
r = c.savedeldata(que);
savedeldata Function
public int savedeldata(string qu)
{
con.Open();
cmd = new SqlCommand(qu, con);
int i = cmd.ExecuteNonQuery();
con.Close();
return i;
}
That's the only solution I can find.
if (ds.Tables["0"].Rows.Count == 1)
{
int r;
string queryt = "DELETE FROM tbl_client";
r = c.savedeldata(queryt);
string que = "INSERT INTO tbl_client(fname, lname, dob, email, gender) SELECT * FROM temp WHERE dob = '" + TextBox3.Text + "'";
r = c.savedeldata(que);
string quer = "UPDATE tbl_client SET uname = '"+ TextBox1.Text +"', upass = '"+ TextBox2.Text +"' WHERE dob = '"+ TextBox3.Text +"'";
r = c.savedeldata(quer);
}
I'm trying to write to a database and am getting the "Input String Was Not In Correct Format" error. I'm assuming it's the data types on the last two columns but I'm not sure how to change. In SQL Server, they are both of the money datatype. Code below:
string query = null;
for (int i = 0; i < result.Tables[0].Rows.Count; i++)
{
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString);
query = "INSERT INTO Upload(Email, TimeStamp, EmployeeId, Name, Title, Department, Race, Gender, AnnualizedBase, AnnualizedTCC) VALUES ('"
+ System.Web.HttpContext.Current.User.Identity.GetUserId() + "', "
+ " '" + DateTime.Now + "', "
+ " '" + result.Tables[0].Rows[i][0].ToString() + "', "
+ " '" + result.Tables[0].Rows[i][1].ToString() + "', "
+ " '" + result.Tables[0].Rows[i][2].ToString() + "', "
+ " '" + result.Tables[0].Rows[i][3].ToString() + "', "
+ " '" + result.Tables[0].Rows[i][4].ToString() + "', "
+ " '" + result.Tables[0].Rows[i][5].ToString() + "', "
+ Convert.ToInt32(result.Tables[0].Rows[i][6]) + ", "
+ Convert.ToInt32(result.Tables[0].Rows[i][7])
+ ")";
con.Open();
SqlCommand cmd = new SqlCommand(query, con);
cmd.ExecuteNonQuery();
con.Close();
}
The error Input string was not in correct format is most likely caused by one of the values in your column not being convertible to an int. If the datatype in SQL is money then you should try and convert to a decimal and not an int. Try this for each row:
decimal num;
if (decimal.TryParse(result.Tables[0].Rows[i][6], out num))
{
// use num because it is indeed a decimal (money in SQL)
}
else
{
// What do you want to do? Log it and continue to next row?
}
Also please read Bobby Tales and example of paratmetrized query.
I get the Syntax Error in UPDATE statement whenever I try to update information in my Access database. I have tried moving things around and adding commas or taking away commas. I am stuck, any suggestions as to what I could do? The error is attached to the second cmd.ExecuteNonQuery(); at the bottom.
if (txtdateId.Text != "")
{
if (txtdateId.IsEnabled == true)
{
cmd.CommandText =
"insert into tbEmp(DateofService, AssociateName, DeviceType, DeviceModel, Serial, Issue, Part1, Part2, Part3, RepairedBy, Campus) Values('" +
txtdateId.Text + "','" + txtEmpName.Text + "','" + txtContact.Text + "','" + txttype.Text +
"','" + txtserial.Text + "','" + txtAddress.Text + "','" + txtpart1.Text + "','" + txtpart2.Text +
"','" + txtpart3.Text + "','" + txtrepaired.Text + "','" + txtcampus.Text + "')";
cmd.ExecuteNonQuery();
BindGrid();
MessageBox.Show("Device Added Successfully");
ClearAll();
}
else
{
cmd.CommandText = "update tbEmp set DateofService = ,'" + txtdateId.Text + ",AssociateName = '" + txtEmpName.Text + ",DeviceType = '" + txtContact.Text + ",DeviceModel = '" + txttype.Text + ",Serial = '" + txtserial.Text + ",Issue = '" + txtAddress.Text + ",Part1 = '" + txtpart1.Text + ",Part2 = '" + txtpart2.Text + ",Part3 = '" + txtpart3.Text + ",RepairedBy = '" + txtrepaired.Text + "where Campus = '" + txtcampus.Text;
cmd.ExecuteNonQuery();
BindGrid();
MessageBox.Show("Device updated");
ClearAll();
}
}
You missed several ' in you statement also you have one extra ' after DateofService. Your statement should be like this:
cmd.CommandText = "update tbEmp set DateofService = '" + txtdateId.Text + "',AssociateName = '" + txtEmpName.Text + "' , ...
Also I strongly recommend you to use parameterized queries to avoid SQL Injection like this:
In SQL:
cmd.CommandText = "update tbEmp set DateofService = #txtdateId ,...";
cmd.Parameters.AddWithValue("txtdateId",txtdateId.Text);
And for Access and OleDB:
cmd.CommandText = "update tbEmp set DateofService = ? , ....";
cmd.Parameters.AddWithValue("DateofService ",txtdateId.Text);
Although specify the type directly and use the Value property is more better than AddWithValue. Check this: Can we stop using AddWithValue() already?
This is solution of your problem, but I'll prefer you do some add validation for SQL injection. First take the textbox value validate it then pass it query.
cmd.CommandText = "update tbEmp set DateofService = '" + txtdateId.Text + "' ,AssociateName = '" + txtEmpName.Text + "' ,DeviceType = '" + txtContact.Text + "',DeviceModel = '" + txttype.Text + "',Serial = '" + txtserial.Text + "',Issue = '" + txtAddress.Text + "',Part1 = '" + txtpart1.Text + "',Part2 = '" + txtpart2.Text + "' ,Part3 = '" + txtpart3.Text + "' ,RepairedBy = '" + txtrepaired.Text + "' where Campus = '" + txtcampus.Text + "'";
i have another question for anyone willing to help. This should be fairly easy but for whatever reason i cant seem to get it right. Im working with visual studio 08 creating a asp.net website in c#
im trying to have a user register, which is all working great, and have the new user default as a user and not a admin. I am using a .MDB as where everything is stored.
is it possible to do this in my initial sql query?
currently my code looks like
strSQL = "Insert into tblUserLogin " +
"(UserFirstName, UserLastName, UserName, UserPassword, UserAddress, UserCity, UserState, UserZipCode, UserEmail, UserPhone, ) values ('" +
UserFirstName + "', '" + UserLastName + "', '" + UserName + "', '" + UserPassword + "', '" + UserAddress +
"', '" + UserCity + "', '" + UserState + "', '" + UserZipCode + "', '" + UserEmail + "', '" + UserPhone +
"')";
// set the command text of the command object
command.CommandType = CommandType.Text;
command.CommandText = strSQL;
// Execute the insert statement
command.ExecuteNonQuery();
this will successfully post everything to the .MDB and it will leave the cell under the column SecurityLevel empty.
i attempted to add
"(UserFirstName, UserLastName, UserName, UserPassword, UserAddress, UserCity, UserState, UserZipCode, UserEmail, UserPhone, SecurityLevel=U )
but this did not work as i hoped it would. Is there a simple way to have that value SecurityLevel default to U without anyone having to specify it?
thank you for your time
If I understand you correctly just use a const value 'U' for SecurityLevel column
strSQL = "INSERT INTO tblUserLogin " +
"(UserFirstName, UserLastName, " +
" UserName, UserPassword, " +
" UserAddress, UserCity, " +
" UserState, UserZipCode, " +
" UserEmail, UserPhone, SecurityLevel) " +
"VALUES (" +
UserFirstName + "', '" + UserLastName + "', '" +
UserName + "', '" + UserPassword + "', '" +
UserAddress + "', '" + UserCity + "', '" +
UserState + "', '" + UserZipCode + "', '" +
UserEmail + "', '" + UserPhone + "', 'U')"; // pass a const value for SecurityLevel column
// the rest of your code goes here
On a side note: Your code is vulnerable to sql-injections. Learn and use prepared (parameterized) statements instead of dynamically building a query strings.
Note: I'm building a practice project where my trainer has forbid me to parameterize. I am aware of the security risks, but the site will not be deployed. I'm using a select scope_identity method to grab an auto-incremented value from the SubmissionId column of my table Submissions.
I want to insert that value into two other tables; I've got newSubID declared as a var and I use it in the insert statements, but I get the error message
The name "newSubID" is not permitted in this context. Valid expressions are constants, constant expressions, and (in some contexts) variables. Column names are not permitted.
What am I missing here?
Here's my code:
protected void BtnSubmit_Click(object sender, EventArgs e)
{
string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString;
String subQuery = "INSERT INTO Submission (Coverage, CurrentCoverage, PrimEx, Retention, EffectiveDate, Commission, Premium, Comments) VALUES ('" + TbCoverage.Text + "','" + TbCurrentCoverage.Text + "','" + TbPrimEx.Text + "','" + TbRetention.Text + "','" + TbEffectiveDate.Text + "','" + TbCommission.Text + "','" + TbPremium.Text + "','" + TbComments.Text + "')"
+ "SELECT CAST (SCOPE_IDENTITY() AS int)";
using (SqlConnection sqlConn = new SqlConnection(connectionString))
{
sqlConn.Open();
SqlCommand subCmd = new SqlCommand(subQuery, sqlConn);
using (subCmd)
{
subCmd.ExecuteNonQuery();
var newSubID = (Int32)subCmd.ExecuteScalar();
String custQuery = "INSERT INTO Customer (CustId, CustName, SicNaic, CustAdd, CustCity, CustState, CustZip, SubId) VALUES ('" + TbCustId.Text + "', '" + TbCustName.Text + "', '" + RblSicNaic.SelectedItem + "', '" + TbCustAddress.Text + "', '" + TbCustCity.Text + "', '" + DdlCustState.SelectedItem + "', '" + TbCustZip.Text + "', newSubID)";
String broQuery = "INSERT INTO Broker (BroId, BroName, BroAdd, BroCity, BroState, BroZip, EntityType, SubId) VALUES ('" + TbBroId.Text + "', '" + TbBroName.Text + "', '" + TbBroAddress.Text + "', '" + TbBroCity.Text + "', '" + DdlBroState.SelectedItem + "', '" + TbBroZip.Text + "', '" + DdlEntity.SelectedItem + "', newSubID)";
SqlCommand custCmd = new SqlCommand(custQuery, sqlConn);
SqlCommand broCmd = new SqlCommand(broQuery, sqlConn);
using (custCmd)
using (broCmd)
{
custCmd.ExecuteNonQuery();
broCmd.ExecuteNonQuery();
Response.Redirect("~/View.aspx?ProductId=" + newSubID);
}
This is called up on the next page like so (I have left the errors as they are in the interest of helping whomever may need to see the problem and solutions, which are listed in answers below):
string x = Request.QueryString["SubmissionId"];
string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString;
string editCustQuery = "SELECT CustName, SicNaic, CustCity, CustAdd, CustState, CustZip FROM Customer WHERE SubId =" + x;
using (SqlConnection editConn = new SqlConnection(connectionString))
{
editConn.Open();
using (SqlCommand CustCommand = new SqlCommand(editCustQuery, editConn))
{
SqlDataReader dr = CustCommand.ExecuteReader();
dr.Read();
LblCustName.Text = dr.GetString(0);
LblSicNaic.Text = dr.GetString(1);
LblCustCity.Text = dr.GetString(2);
LblCustAddress.Text = dr.GetString(3);
LblCustState.Text = dr.GetString(4);
LblCustZip.Text = dr.GetInt32(5).ToString();
}
It's because you're not concatenating the newSubID into the custQuery / btoQuery SQL statements, but instead your using the literal text "newSubID" in the statement which is invalid here as it will assume "newSubID" is a column name.
i.e.
String custQuery = "INSERT INTO Customer (CustId, CustName, SicNaic, CustAdd, CustCity,
CustState, CustZip, SubId)
VALUES ('" + TbCustId.Text + "', '" + TbCustName.Text + "', '" + RblSicNaic.SelectedItem +
"', '" + TbCustAddress.Text + "', '" + TbCustCity.Text + "', '" +
DdlCustState.SelectedItem + "', '" + TbCustZip.Text + "'," +
newSubID.toString() + ")";
Of course, I'm only giving an answer that uses dynamic SQL like this because of your disclaimer and is not what I'd do in real life!
Answer of AdaTheDev is correct.
I think you have another issue. If you do ExecuteNonQuery and then ExecuteScalar with the same command, you'll insert twice. Use an out-parameter for your scope_id and call only exenonquery or call just exescalar.
//subCmd.ExecuteNonQuery();
var newSubID = (Int32)subCmd.ExecuteScalar();