I'm trying to add a record to a table with data used from a form. My code looks like this:
private void button4_Click(object sender, EventArgs e)
{
using (SqlConnection connect = new SqlConnection(#"Data Source=(LocalDB)\v11.0;" +
#"AttachDbFilename=C:\Development\C-Sharp\LockItUp\Lockitup.mdf;Integrated Security=True"))
{
string theVault = #lblVault.Text.Replace(#"\", #"\\");
string stmt = #"INSERT INTO Users (username,password,folderloc,fullname,email,cellphone)" +
" VALUES ('" + txtUsrName.Text + "', '" + txtUserPassword.Text + "', '" + theVault + "', '" +
txtFullname.Text + "', '" + txtEmail.Text + "', '" + txtCellPhone.Text + "')";
using(SqlCommand cmd = new SqlCommand(stmt, connect))
{
try
{
connect.Open();
cmd.ExecuteNonQuery();
connect.Close();
}
catch (Exception ex)
{
MessageBox.Show("Error: " + ex);
return;
}
}
PanelSwitch("Home");
RefreshMenu();
}
}
However, every time run it, I get the error message 'String or binary data would be truncated.' I pin pointed the error to the folderloc field. A directory goes in it. I'm currently trying to put the value C:\Development\locker in it, but I keep getting the error. How can I resolve this problem?
You've got several issues with your code. First, to address the error you are receiving String or binary data would be truncated. The reason for this is that the field in the table isn't big enough to store the data. Go into your database and look at the Users table and look at each field and make sure the field is defined with enough width to store the data (e.g., look for VARCHAR(20) or something and change it to something like VARCHAR(500)).
Secondly, as #David suggested, you need to address your issue of SQL Injection. You are directly inserting dynamic values into your SQL statement. This is bad news. Microsoft has a good article on this subject and how to avoid it.
Thirdly, you should not store your passwords as plain text. They should be salted and hashed. Look at this article for a good tutorial on this.
Related
the code is below and the error starting from sqlCommand cmd the 13th line of this code
private void button2_Click(object sender, EventArgs e)
{
if (StudenUsn.Text == "" )
{
MessageBox.Show("Enter The Student Number");
} else {
Con.Open();
String query = "update Student_tbl set StdName='" + StudName.Text + "',where FatherName='" + FtName.Text + "',where MotherName='" + MtName.Text + "',where StdAddress='" + Address.Text + "',where Collage ='" + Collage.Text + "'set StdRoom = " + StRmNum.SelectedValue.ToString()+",StdStatus = '"+ StudSt.SelectedItem.ToString() + "' where StdUsn ='"+StudenUsn+ "')";
SqlCommand cmd = new SqlCommand(query, Con);
cmd.ExecuteNonQuery();
MessageBox.Show("Room Successfully Updates");
Con.Close();
FillStudentDGV();
}
}
Your code should look more like:
private void button2_Click(object sender, EventArgs e)
{
if (StudenUsn.Text == "" )
{
MessageBox.Show("Enter The Student Number");
} else {
var query = #"
update Student_tbl
set
StdName=#sn,
FatherName=#fn,
MotherName=#mn,
StdAddress=#sa,
Collage=#c,
StdRoom=#sr,
StdStatus=#ss
where
StdUsn=#su";
using var con = new SqlConnection(YOUR_CONN_STR_HERE);
using var cmd = new SqlCommand(query, con);
cmd.Parameters.AddWithValue(#sn, StudName.Text);
cmd.Parameters.AddWithValue(#fn, FtName.Text);
cmd.Parameters.AddWithValue(#mn, MtName.Text);
cmd.Parameters.AddWithValue(#sa, Address.Text);
cmd.Parameters.AddWithValue(#c, Collage.Text);
cmd.Parameters.AddWithValue(#sr, StRmNum.SelectedValue);
cmd.Parameters.AddWithValue(#ss, StudSt.SelectedItem);
cmd.Parameters.AddWithValue(#su, StudenUsn);
con.Open();
cmd.ExecuteNonQuery();
con.Close();
MessageBox.Show("Room Successfully Updates");
FillStudentDGV();
}
}
There are good reasons to avoid using AddWithValue if you use SQLServer which you can get into at a later date if you want, but it's convenient for me (who doesn't know the types and widths of your columns) dealing with the current massive elephant in the room which is your SQL is massively vulnerable to a hacking technique known as sql injection (and to a lesser extent it would blow up with an error for any student whose name included an apostrophe) - using AddWithValue might make your query slightly slower, but better that than it be the cause of the next data breach; learn how to write SQLs right, right now
Never ever take data supplied by a user and concatenate it into an SQL string. Doing so essentially, in most cases, gives the user access to your database. So many big companies whose developers should know better, put up expensive firewalls and security and then let anyone in via this back door anyway; sql injection prone systems are one of the leading causes of hacks in the world today
Always use #parameter placeholders in the SQL for user data and add a parameter to the command's parameters collection, containing the data
Now on the topic of your actual error; the pattern for an update is
update table
set col1=#param1, col2=#param2 ...
where (some conditions)
You have one where and one set. If there is some conditional aspect to your set, like you only want to update the student name/address if it is currently null then you can do like:
update table
set
name=case when name is null then #n else name end,
address=case when address is null then #a else address end
where (some conditions)
Or more simply
update table
set
name=coalesce(name, #n)
address=coalesce(address, #a)
where (some conditions)
You can't mix n match and say "where this=that where this2=that2 set this3=that3" - that's a syntax error. Where is for picking the row you want to update and set is for starting a block of commas separated columns and values the row data is to be updated to.
Strive to write your sql nicely formatted inside an #string; it's a programming language all of its own, and will be easier to debug if it's laid out nicely
Can u try with it ?
String query = "update Student_tbl set StdName='" + StudName.Text + "',StdRoom = '" + StRmNum.SelectedValue.ToString()+"',StdStatus = '"+ StudSt.SelectedItem.ToString() + "' where FatherName='" + FtName.Text + "' and MotherName='" + MtName.Text + "' and StdAddress='" + Address.Text + "' and Collage ='" + Collage.Text + "' and StdUsn ='"+StudenUsn+ "'";
Im tasked to update selected information however not delete the previous data added...How do I update without replacing the old data and is it possible to view it if necessary?
Heres a part of my code:
MySqlConnection conn = new MySqlConnection(mycon);
string Query = "update mydb.client set clientLN='" + txtClientLName.Text + "', clientFN='" + txtClientFName.Text + "', clientMN='" + txtClientMName.Text + "', clientType='" + cmbTypeMembership.Text + "', clientMembershipType='" + cmbRates.Text + "', clientMembershipValidity='" + Days.ToString() + "', clientMembershipStatus='" + validity + "' where clientID='" + clientID + "';";
conn.Open();
MySqlCommand myCommand = new MySqlCommand(Query, conn);
myReader = myCommand.ExecuteReader();
conn.Close();
MessageBox.Show("Client Successfully Renewed!");
In sql, an update without replacing old data is called an insert
It sounds like you need to keep the old values related to the client around for [backup, audit, some other reason]. Two possible approaches;
1) Keep a archive table where you insert the existing record (with a timestamp) before issuing the update.
2) Make you main table effective-dated (but your application will need to know how to deal w/ effective-dated records).
Is there a way to store TEXT in SQLite database without SQLite trying to parse it?
Ran into a problem where when you store TEXT that is similar to SQLite query, it tries to parse it for some reason.
Query I use to save TEXT: "insert into tableName (Name, DateCreated, Reminder, Content) values ('name', 'currentDate', 'reminder', 'content')".
Similar text I'm trying to save: "SELECT NAME FROM sqlite_master WHERE TYPE='table' ORDER BY NAME".
When i try to save something like that, it says: Error: SQL logic error or missing database near "table":syntax error
Please note that values (name, currentDate, reminder, content) are not hard coded, they are passed as strings. actual code is like below:
SQLiteCommand command = new SQLiteCommand("insert into " + cateName + " (Name, DateCreated, Reminder, Content) values ('" + noteName + "', '" + currentDate + "', '" + reminder + "', '" + content + "')", connection);
Thanks for any input.
As I suspect, the problem is that you're putting your values directly into the SQL - without even trying to escape them. Don't do that. As well as the problems you're seeing, you've opened yourself up to a SQL injection attack. Use parameterized SQL instead, and specify values for the parameters.
For example:
// It's not clear what cateName is, but I'll assume *that* bit is valid...
string sql = new SQLiteCommand("insert into " + cateName +
" (Name, DateCreated, Reminder, Content) values " +
"(#Name, #DateCreated, #Reminder, #Content)");
using (var command = new SQLiteCommand(sql, connection))
{
command.Parameters.Add("#Name", SQLiteType.Text).Value = noteName;
command.Parameters.Add("#DateCreated", SQLiteType.DateTime).Value = currentDate;
command.Parameters.Add("#Reminder", SQLiteType.Text).Value = reminder;
command.Parameters.Add("#Content", SQLiteType.Text).Value = content;
command.ExecuteNonQuery();
}
I keep getting an error when I attempt to insert values into a Access database.
The error is syntactic, which leads to the following exception:
OleDbException was unhandled Syntax error in INSERT INTO statement.
private OleDbConnection myCon;
public Form1()
{
InitializeComponent();
myCon = new OleDbConnection(#"Provider=Microsoft.Jet.OLEDB.4.0; Data Source=C:\File.mdb");
}
private void insertuser_Click(object sender, EventArgs e)
{
OleDbCommand cmd = new OleDbCommand();
myCon.Open();
cmd.Connection = myCon;
cmd.CommandType = CommandType.Text;
cmd.CommandText = "INSERT INTO User ([UserID], [Forename], [Surname], " +
"[DateOfBirth], [TargetWeight], [TargetCalories], [Height]) " +
"VALUES ('" + userid.Text.ToString() + "' , '" +
fname.Text.ToString() + "' , '" +
sname.Text.ToString() + "' , '" +
dob.Text.ToString() + "' , '" +
tarweight.Text.ToString() + "' , '" +
tarcal.Text.ToString() + "' , '" +
height.Text.ToString() + "')";
cmd.ExecuteNonQuery();
myCon.Close();
}
Well, you haven't specified what the error is - but your first problem is that you're inserting the data directly into the SQL statement. Don't do that. You're inviting SQL injection attacks.
Use a parameterized SQL statement instead. Once you've done that, if you still have problems, edit this question with the new code and say what the error is. The new code is likely to be clearer already, as there won't be a huge concatenation involved, easily hiding something like a mismatched bracket.
EDIT: As mentioned in comments, Jet/ACE is vulnerable to fewer types of SQL injection attack, as it doesn't permit DML. For this INSERT statement there may actually be no vulnerability - but for a SELECT with a WHERE clause written in a similar way, user input could circumvent some of the protections of the WHERE clause. I would strongly advise you to use parameterized queries as a matter of course:
They mean you don't have to escape user data
They keep the data separate from the code
You'll have less to worry about if you ever move from Jet/ACE (whether moving this particular code, or just you personally starting to work on different databases)
For other data types such as dates, you don't need to do any work to get the data into a form appropriate for the database
(You also don't need all the calls to ToString. Not only would I expect that a property called Text is already a string, but the fact that you're using string concatenation means that string conversions will happen automatically anyway.)
I posted this as a comment to the duplicate question at: Syntax error in INSERT INTO statement in c# OleDb Exception cant spot the error
Put brackets [] around the table name
"User". It's a reserved word in SQL
Server.
"User" is also a reserved word in Access (judging by the provider in your connection string).
But I completely agree with Jon--if you fix your current implementation, you are just opening up a big security hole (against your User table, no less!)
This problem may occur if your database table contains column names that use Microsoft Jet 4.0 reserved words.
Change the column names in your database table so that you do not use Jet 4.0 reserved words.
If TargetWeight, Height, and TargetCalories are floating-point or integer values, they don't need to be surrounded by quotes in the SQL statement.
Also, not directly related to your question, but you should really consider using a parameterized query. Your code is very vulnerable to SQL injection.
public decimal codes(string subs)
{
decimal a = 0;
con_4code();
query = "select SUBJINTN.[SCODE] from SUBJINTN where SUBJINTN.[ABBR] = '" + subs.ToString() + "'";
cmd1 = new OleDbCommand(query, concode);
OleDbDataReader dr = cmd1.ExecuteReader();
here is error in dr it says syntax error ehile in DBMS its working Well
if (dr.Read())
{
a = dr.GetDecimal(0);
MessageBox.Show(a.ToString());
}
return a;
}
After this
cmd.CommandText="INSERT INTO User ([UserID], [Forename], [Surname], [DateOfBirth], [TargetWeight], [TargetCalories], [Height]) Values ('" + userid.Text.ToString() + "' , '" + fname.Text.ToString() + "' , '" + sname.Text.ToString() + "' , '" + dob.Text.ToString() + "' , '" + tarweight.Text.ToString() + "' , '" + tarcal.Text.ToString() + "' , '" + height.Text.ToString() + "')";
check what this contains, maybe [DateOfBirth] has illegal format
I'm trying to insert a date into a SQL table, but it when the program runs it gives the following error.
Conversion failed when converting date and/or time from character string.
string dateReleased = DateReleasedDate.Value.ToString("YYYY-MM-DD");
string myQuery = "INSERT INTO GameTbl (gameName, genreID, players, online, dateReleased, dateAdded, developerID, publisherID, consoleID) VALUES('"
+ GameNameTxt.Text + "', '" + GenreCombo.SelectedValue + "', '" + PlayersNUD.Value + "', '" + OnlineCombo.SelectedText + "', '"
+ dateReleased + "', 'GETDATE()', '" + DeveloperCombo.SelectedValue + "', '"
+ PublisherCombo.SelectedValue + "','" + ConsoleCombo.SelectedValue + "')";
Please use parametrized queries. My eyes hurt when I see string concatenations used to construct SQL queries:
using (var conn = new SqlConnection("SOME CONNECTION STRING"))
using (var cmd = new SqlCommand(conn))
{
conn.Open();
cmd.CommandText = "INSERT INTO GameTbl (gameName, genreID, players, online, dateReleased, developerID, publisherID, consoleID) VALUES (#gameName, #genreID, #players, #online, #dateReleased, #developerID, #publisherID, #consoleID)";
cmd.Parameters.AddWithValue("#gameName", GameNameTxt.Text);
cmd.Parameters.AddWithValue("#genreID", GenreCombo.SelectedValue);
cmd.Parameters.AddWithValue("#players", PlayersNUD.Value);
cmd.Parameters.AddWithValue("#online", OnlineCombo.SelectedText);
cmd.Parameters.AddWithValue("#dateReleased", DateReleasedDate.Value);
cmd.Parameters.AddWithValue("#developerID", DeveloperCombo.SelectedValue);
cmd.Parameters.AddWithValue("#publisherID", PublisherCombo.SelectedValue);
cmd.Parameters.AddWithValue("#consoleID", ConsoleCombo.SelectedValue);
var result = cmd.ExecuteNonQuery();
...
}
As far as the dateAdded column is concerned I would simply remove it from the INSERT and add it a default value directly in the SQL database.
Notice how you are directly passing DateTime instances and you leave ADO.NET handle the formats. As a bonus your code is safe against SQL injections.
DateReleasedDate.Value.ToString("yyyy-MM-dd");
The problem is you put GETDATE() into single-quotes. It is trying to convert the string 'GETDATE()' into a date.
The best way to pass a date into SQL from .net, IMO, is to use the .ToOADate function.
The function passes in a numerical representation of the date that will work on any database datetime \ date field regardless of the regional setup.
Some info for you: ToOADate