asp.net SQL Server insert statement tidyup + error - c#

I have a form which inserts data into a database.
There are certain fields that are not always going to be needed.
When I leave these blank in my code I get a error saying.
Column name or number of supplied values does not match table
definition.
This is how I have the database setup. SQL Server 2008
[youthclubid]
[youthclubname]
[description]
[address1]
[address2]
[county]
[postcode]
[email]
[phone]
Here is the code that I have connecting to the database and doing the insert.
connection.Open();
cmd = new SqlCommand("insert into youthclublist values ('" + youthclubname.Text + "', '" + description.Text + "','" + address1.Text + "','" + address2.Text + "', '" + county.Text + "', '" + postcode.Text + "', '" + email.Text + "', '" + phone.Text + "')", connection);
cmd.ExecuteNonQuery();

You have two major problems:
1) concatenating together your SQL statement is prone to SQL injection attacks - don't do it, use parametrized queries instead
2) You're not defining which columns you want to insert in your table - by default, that'll be all columns, and if you don't provide values for all of them, you'll get that error you're seeing.
My recommendation: always use a parametrized query and explicitly define your columns in the INSERT statement. That way, you can define which parameters to have values and which don't, and you're safe from injection attacks - and your performance will be better, too!
string insertStmt =
"INSERT INTO dbo.YouthClubList(Youthclubname, [Description], " +
"address1, address2, county, postcode, email, phone) " +
"VALUES(#Youthclubname, #Description, " +
"#address1, #address2, #county, #postcode, #email, #phone)";
using(SqlConnection connection = new SqlConnection(.....))
using(SqlCommand cmdInsert = new SqlCommand(insertStmt, connection))
{
// set up parameters
cmdInsert.Parameters.Add("#YouthClubName", SqlDbType.VarChar, 100);
cmdInsert.Parameters.Add("#Description", SqlDbType.VarChar, 100);
.... and so on
// set values - set those parameters that you want to insert, leave others empty
cmdInsert.Parameters["#YouthClubName"].Value = .......;
connection.Open();
cmdInsert.ExecuteNonQuery();
connection.Close();
}

The first major issue is that you are concatenating inputs in the query. This makes your application highly vulnerable to SQL Injection. Do not do this. Use a parametrized query.
The regular syntax for insert statement is like this:
Insert into <TableName> (Col1, Col2...Coln) values (val1, val2...valn)
If you need to insert only a selected set of columns, you need to provide the list of columns you are inserting data into in the column list.
If you do not specify the column list, the indication is that you are inserting data to each one of them.
So you may check for the input and if it is not there, you may omit the respective column.
The other better way is use a stored proc. That will ease out the issue.

This not way to do the code you make use of SqlParameter for this kind of statement.
So your code something like
SqlConnection thisConnection = new SqlConnection(ConfigurationManager.ConnectionStrings["Northwind_ConnectionString"].ConnectionString);
//Create Command object
SqlCommand nonqueryCommand = thisConnection.CreateCommand();
try
{
// Create INSERT statement with named parameters
nonqueryCommand.CommandText = "INSERT INTO Employees (FirstName, LastName) VALUES (#FirstName, #LastName)";
// Add Parameters to Command Parameters collection
nonqueryCommand.Parameters.Add("#FirstName", SqlDbType.VarChar, 10);
nonqueryCommand.Parameters.Add("#LastName", SqlDbType.VarChar, 20);
nonqueryCommand.Parameters["#FirstName"].Value = txtFirstName.Text;
nonqueryCommand.Parameters["#LastName"].Value = txtLastName.Text;
// Open Connection
thisConnection.Open();
nonqueryCommand.ExecuteNonQuery();
}
catch (SqlException ex)
{
// Display error
lblErrMsg.Text = ex.ToString();
lblErrMsg.Visible = true;
}
finally
{
// Close Connection
thisConnection.Close();
}

You need to tell SQL server that which field you want to insert like
insert into youthclublist(youthclubid, youthclubname, ....) values ('" + youthclubname.Text + "', '" + description.Text + "'.....
and you are fine.

Though new into programming, the easiest way i know to insert into a database is to create a "save" stored procedure, which is then called up through your connection string. Believe me, this is the best way.

Another way around is to use LINQ to SQL. i found this much more easier. Follow this steps.
Add a new LINQ to SQL Classes to your project. Make sure the file extension is '.dbml'. Name it your name of choice say "YouthClub.dbml"
Connect your Database to Visual Studio using the Server Explorer
Drag your table to the OR Designer.(I'm not allowed to post images).
You can now save to the Database with this code
//Create a new DataContext
YouthClubDataContext db = new YouthClubDataContext();
//Create a new Object to be submitted
YouthClubTable newYouthClubRecord = new YouthClubTable();
newYouthClubRecord.youthlubname = txtyouthclubname.Text;
newYouthClubRecord.description = txtdescription.Text;
newYouthClubRecord.address1 = txtaddress1.Text;
newYouthClubRecord.address2 = txtaddress2.Text;
newYouthClubRecord.county = txtcounty.Text;
newYouthClubRecord.email = txtemail.Text;
newYouthClubRecord.phone = txtphone.Text;
newYouthClubRecord.postcode = txtpostcode.Text;
//Submit to the Database
db.YouthClubTables.InsertOnSubmit(newYouthClubRecord);
db.SubmitChanges();
Hope this time I have given a real answer

Related

Execute UPDATE command

I wrote that to update my SQL table.
mycmd.CommandText = "UPDATE savedinfo SET User_id='" + Login.GetUserID().ToString() + "', Date='" + DateTime.Now.ToLongDateString() + "', Evaluate='" + activeEvaluate.ToString() + "', TimeStart='" + dtCurrentTime1.ToLongTimeString() + "', TimeEnd='" +dtCurrentTime2.ToLongTimeString() + "' , Salary= '" + todaySalary.Text +"'";
mycmd.Connection = con;
mycmd.ExecuteNonQuery();
When getting to mycmd.ExecuteNonQuery(); I got an error:
An unhandled exception of type 'System.Data.SqlClient.SqlException'
occurred in System.Data.dll
Additional information: String or binary data would be truncated.
The statement has been terminated.
What is the problem here?
Thanks
The error implies that you are attempting to insert a value which is to big for the column length within the database. Please look through your database schema and identify which column is causing the issue.
Looking at the snippet of code I have a few other observations which maybe of some help.
Does the Update statement require a where clause?
Do use parameterised queries as this will help against SQL injection attacks.
Using statement are very helpful in clearing and cleaning up an objects, in this case a using statement help managing the open connections to the database.
If you wish to check for valid string lengths before sending them to the database check the arguments before creating connections etc. ideally these check would be carried out in your business logic layer.
if (activeEvaluate.Length > 5)
{
throw new ArgumentException("activeEvaluate");
}
using (SqlConnection connection = new SqlConnection(ConnString))
{
using (SqlCommand cmd = connection.CreateCommand())
{
cmd.CommandText = "UPDATE savedinfo set User_id= #UserId, Date = #Date, Evaluate = #Evaluate, TimeStart = #TimeStart, TimeEnd = #TimeEnd, Salary = #Salary ";
cmd.Parameters.AddWithValue("#UserId", Login.GetUserID());
cmd.Parameters.AddWithValue("#Date", DateTime.Now.ToLongDateString());
cmd.Parameters.AddWithValue("#Evaluate", activeEvaluate.ToString());
cmd.Parameters.AddWithValue("#TimeStart", dtCurrentTime1.ToLongTimeString());
cmd.Parameters.AddWithValue("#TimeEnd", dtCurrentTime2.ToLongTimeString());
cmd.Parameters.AddWithValue("#Salary", todaySalary.Text);
cmd.Connection.Open();
cmd.ExecuteNonQuery();
}
}

Insert into DateTime (from C# to MySQL)

I Just Keep Having this Error:
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '2014-10-08 19:39:57)' at line 1
public string ObtenerFechaHora()
{
string query = "select CURRENT_TIMESTAMP() as Fecha";
OpenConnection();
MySqlCommand cmd = new MySqlCommand(query, connection);
cmd.ExecuteNonQuery();
DateTime e = (DateTime)cmd.ExecuteScalar();
CloseConnection();
return e.ToString("yyyy-MM-dd H:mm:ss");
}
Then i insert ("Fecha" is the DateTime Column)
string query = "INSERT INTO actividad (idTerminal, Proceso, Nombre, Tiempo, Fecha) VALUES('" + idTerminal + "', '" + Proceso + "', '" + Nombre + "', '1,'" + this.ObtenerFechaHora() + ")";
I been used loot of formats and i keep having error, for example:
e.ToString("yyyy-MM-dd H:mm:ss");
e.ToString("yyyy-MM-dd HH:mm:ss");
e.ToString("dd-MM-yyyy H:mm:ss");
e.ToString("yyyy-dd-MMH:mm:ss");
Also with "/" instead of "-"
Any help here?
The problem isn't with the format of the datetime string; the problem is in the SQL text of the INSERT statement, right before the value is appended. For debugging this, you could output the query string and inspect it.
The problem is in the SQL text here:
+ "', '1,'" +
There needs to be a comma between that literal and the next column value. It looks like you just missed a single quote:
+ "', '1','" +
^
A potentially bigger problem is that your code appears to be vulnerable to SQL Injection. Consider what happens when one of the variables you are including into the SQL text includes a single quote, or something even more nefarios ala Little Bobby Tables. http://xkcd.com/327/.
If you want a column value to be the current date and time, you don't need to run a separate query to fetch the value. You could simply reference the function NOW() in your query text. e.g.
+ "', '1', NOW() )";
You excuted twice
//cmd.ExecuteNonQuery();
DateTime e = (DateTime)cmd.ExecuteScalar();
Should be only one time.
Then like #sgeddes said in the comments use parameterized queries, they avoid errors and sql injections.
The approach that you have used is not the best approach to write SQL command. You should use sql parameters in the Query. Your code is vulnerable to SQL Injected and obviously it is not the best approach.
Try using something like this:
string commandText = "UPDATE Sales.Store SET Demographics = #demographics "
+ "WHERE CustomerID = #ID;";
SqlCommand command = new SqlCommand(commandText, connection);
command.Parameters.Add("#ID", SqlDbType.Int);
command.Parameters["#ID"].Value = customerID;

Storing Data in SQLite

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();
}

How to use LAST_INSERT_ID() in c# windows form?

In database I have three tables-
patient(patientID,fName,lName)
illness(diseaseID,diseaseName)
patientDisease(patientID, diseaseID, dateChecked)
patientID and diseaseID are index.
So on in c# I have three textboxes fNameTxt and lNameTXT, diseaseTxt.I want to store the name in patient table and disease name in illness table. Besides, I have to record patientID and diseaseID in patientDisease table as well. For patient table, I used following code. I knew, I can use
SET #variable = LAST_INSERT_ID()
to get the id, but realised c#(visual studio) doesnt recognize it. Basically, I couldnt make the overall statement. Could anybody help me to get through this condition please.
string connStr = #"server=localhost; DATABASE=mario;User ID=root;Password=;";
MySqlConnection conn1 = new MySqlConnection();
conn1.ConnectionString = connStr;
MySqlCommand cmd = conn1.CreateCommand();
cmd.CommandText = "INSERT INTO patient(patientID,fName, lName)"
+ "Values("NULL",'" + fNameTxt.Text + "','" + lNameTxt.Text + "');";
conn1.Open();
cmd.ExecuteNonQuery();
I searched some other questions here, but they are almost about suggesting the use of LAST_INSERT_ID() but not how to use it.
It will be much better if you use stored procedures
INSERT INTO patient (patientID,patientID,lName)
VALUES("NULL",'" + fNameTxt.Text + "','" + lNameTxt.Text + "');
SET #last_id_in_patient = LAST_INSERT_ID();
INSERT INTO patientDisease (patientID,diseaseID,dateChecked)
VALUES( #last_id_in_patient ,NULL,'text'); # use ID in second table";
Now You can update your PatientDisease table for particular PatientId.
You can use this to get the last inserted id:
"SELECT * FROMtable(column) WHERE id = last_insert_id();
And use this if you want to insert a last id:
"INSERT INTO table(column) VALUES (LAST_INSERT_ID())";
Hope this might be useful.

How to solve a syntax error when using this INSERT INTO statement and the .NET OleDb namespace?

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

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