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I am trying to enter the value of a textbox in c# into a field in a database that I have in access. For some reason I keep getting the error saying:
'An unhandled exception of type 'System.Data.OleDb.OleDbException' occurred in System.Data.dll
Additional information: Syntax error in INSERT INTO statement.'
Can't quite see what is wrong, this is the first time I have attempted to do this in a project so I am not too experienced with it. This is my code:
OleDbConnection connection = new OleDbConnection(CONNECTION STRING GOES HERE);
connection.Open();
string playerName = textBox[i].Text;
string query = "INSERT INTO (TotalPlayerName)(Player Name) VALUES(" + playerName + ")";
OleDbCommand command = new OleDbCommand(query, connection);
command.ExecuteNonQuery();
if it helps then the database is called 'Database' the table is called 'TotalPlayerName' and the field is called 'Player Name'
The correct code to do your task is
string cmdText = "INSERT INTO TotalPlayerName ([Player Name]) VALUES(?)";
using(OleDbConnection connection = new OleDbConnection(...))
using(OleDbCommand command = new OleDbCommand(cmdText, connection))
{
connection.Open();
command.Parameters.Add("#p1", OleDbType.VarWChar).Value = textBox[i].Text;
int result = command.ExecuteNonQuery();
if(result > 0)
MessageBox.Show("Record Inserted");
else
MessageBox.Show("Failure to insert");
}
This approach fixes three problems:
The connection and the command object should be disposed at the end
(see using statement)
Every value that you need to pass to the query should be passed as
parameter
If a field name (or table name) has embedded spaces you should enclose
it between square brackets
(The messages below the ExecuteNonQuery are there only as an example to check the return value of ExecuteNonQuery)
Remember also that if your table has more than this field and some of the other fields don't accept null values you should provide some value also for them.
For example
string cmdText = #"INSERT INTO TotalPlayerName ([Player Name], FieldB)
VALUES(?, ?)";
command.Parameters.Add("#p1", OleDbType.VarWChar).Value = textBox[i].Text;
command.Parameters.Add("#p2", OleDbType.VarWChar).Value = "ValueForFieldB";
Just remember to strictly follow the order of the ? when you add your parameter values
Related
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This is my code:
private void button1_Click(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection();
con.ConnectionString = "data source = LAPTOP-ULT25NKH; database = college;integrated security = True";
SqlCommand cmd = new SqlCommand();
cmd.Connection = con;
cmd.CommandText = "select * from teacher where tID = " + textBox1.Text + "";
DataSet DS = new DataSet();
SqlDataAdapter DA = new SqlDataAdapter(cmd);
DA.Fill(DS);
dataGridView1.DataSource = DS.Tables[0];
}
but I get this exception:
An exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll but was not handled in user code
Additional information: Incorrect syntax near '='."
Ensure you are properly santizing inputs and using prepared statements; to start down the line for you, try:
cmd.CommandText = "SELECT * FROM teacher WHERE tID = #tID;"
SqlParameter idParam = new SqlParameter("#tID", SqlDbType.NVarChar , 0);
idParam.Value = textBox1.Text;
cmd.Parameters.Add(idParam);
cmd.Prepare();
There are lot of issues in your existing code, I’m mentioning few points brlow.
Please move the connection string to some config file, it’s easy to maintain there.
When you have DataAdapter you don’t need to explicitly open the connection, it does that for you internally.
Please avoid * in select query, mention the columns with alias and use parameterized query to pass the parameters. Or your can write stored procedure and call it. So that I if I’m future you need to modify query, there will be no code change.
If you need to open the connection, please close it or your can use using.
You can add breakpoint and see the value of your query and if you copy this query value and run in sql server directly . This is one way to find the error in the query.
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I am creating a form for alerting the user that the stock for this item in the database is getting the limit or passed right through the limit.
this is my code for checking the quantity of a certain stock
conn.Open();
cmd.Connection = conn;
cmd.CommandText = "select * from tbl_BloodChemistry where Glucose = "+123+" ";
reader = cmd.ExecuteReader();
int count = 0;
while (reader.Read())
{
count = count + 1;
}
if (count == 1)
{
MessageBox.Show("Critical!");
}
conn.Close();
It's not actually the answer, but you have no reason to retrieve all data to collect count of rows. Use SQL COUNT and ExecuteScalar() for this.
Also, it's important to use command Parameters to your query. Don't ever build a query in your way! The input variable, Glucose, is typically retrieved from a TextBox control on either a Windows form or a Web Page. Anything placed into that TextBox control will be put into inputCity and added to your SQL string. This situation invites a hacker to replace that string with something malicious. In the worst case, you could give full control of your computer away.
Instead of dynamically building a string, as shown in the bad example above, use parameters. Anything placed into a parameter will be treated as field data, not part of the SQL statement, which makes your application much more secure.
Using parameterized queries is a three step process:
Construct the SqlCommand command string with parameters.
Declare a SqlParameter object, assigning values as appropriate.
Assign the SqlParameter object to the SqlCommand object's Parameters property.
var glucoseFilterValue = "123";
conn.Open();
cmd.Connection = conn;
cmd.CommandText = "select count(*) from tbl_BloodChemistry where Glucose = #Glucose";
cmd.Parameters.AddWithValue("#Glucose", glucoseFilterValue);
var count = (int) cmd.ExecuteScalar();
if (count == 1)
{
MessageBox.Show("Critical!");
}
conn.Close();
Then you'll make your code more clean and prevent extra loading to your communication channel.
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i have database contain column name Code data type nvarchar(50) i connected to my database by c# and created a SQL command as
string code = "e01";
SqlCommand command = new SqlCommand("select * from inv where code = " + code + ";", conn);
SqlDataReader reader = command.ExecuteReader();
i found an error says
An unhandled exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll
Additional information: Invalid column name 'e01'.
and if i but number instead of e01 it work fine ..
your are missing quotes. Try this:
string code = "e01"
SqlCommand command = new SqlCommand("select * from inv where code = '" + code + "';", conn);
SqlDataReader reader = command.ExecuteReader();
Also, it's recomended use parameters instead concatenating values. This avoid sql injection attacks or sql errors if your code contains special characters, like quotes:
SqlCommand command = new SqlCommand("select * from inv where code = #pCode", conn);
command.Parameters.Add(new SqlParameter("#pCode", code));
SqlDataReader reader = command.ExecuteReader();
You forgot to put quotes around your column value, because e01 is a value and not a column it needs to be surrounded by single quotes.
SqlCommand command = new SqlCommand("select * from inv where code = '" + code + "';", conn);
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i'm making GUI for a database (school project) and I have following problem - when i try to assign resul from select statement to variable i have strange error:
An unhandled exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll
Additional information: Incorrect syntax near ')'.
this is my code:
string sql2 = "SELECT * FROM Car WHERE Make = '#CarID' AND Model = '#CarID2');";
SqlCommand cmd3 = new SqlCommand(sql2, sqlconn);
cmd3.Parameters.AddWithValue("#CarID", model_cbo);
cmd3.Parameters.AddWithValue("#CarID2", make_cbo);
string CarID = cmd3.ExecuteScalar().ToString();
I've looking for the solution for a long time, but haven't found anything, so please help
This is my code for connection with DB:
public CarSpec()
{
InitializeComponent();
connectDB();
this.conn = new OleDbConnection("PROVIDER=SQLOLEDB;Data Source=HENIU;Initial Catalog=ServiceStation; Integrated Security=SSPI;");
conn.Open();
}
public void connectDB()
{
sqlconn = new SqlConnection(#"Data Source=HENIU; Initial Catalog=ServiceStation; Integrated Security=TRUE;");
sqlconn.Open();
da = new SqlDataAdapter();
}
There are three problems in your code:
There is a parenthesys not needed at the end of the WHERE clause
The parameters should be free from the single quotes. (Otherwise the will be treated as string literals)
The ExecuteScalar returns just a the first column of the first row.
You cannot be certain that this will be the carID.
Use instead
string sql2 = "SELECT * FROM Car WHERE Make = #CarID AND Model = #CarID2";
SqlCommand cmd3 = new SqlCommand(sql2, sqlconn);
cmd3.Parameters.AddWithValue("#CarID", model_cbo);
cmd3.Parameters.AddWithValue("#CarID2", make_cbo);
SqlDataReader reader = cmd3.ExecuteReader()
if(reader.Read())
{
int carID = Convert.ToInt32(reader["CarID"]);
}
Here I am assuming that a carID is a number and not a string (as it should be). However, if it is a string then you could change the line to
string carID = reader["CarID"].ToString();
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SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["RegistrationConnectionString"].ConnectionString);
conn.Open();
string checkUser = " select count(*) form Userdata where Username='" + TextBoxUN.Text + "' ";
SqlCommand cmd = new SqlCommand(checkUser,conn);
if (temp==1)
{
Response.Write("User Already Exists");
}
conn.Close();
System.Data.SqlClient.SqlException was unhandled by user code
HResult=-2146232060 Message=Incorrect syntax near 'Userdata'
int temp= Convert.ToInt32(cmd.ExecuteScalar().ToString());
The error message says:
Incorrect syntax near 'Userdata'
That tells you that the SQL parser gave up at the word Userdata because the syntax no longer made sense, which usually means that the actual error is close before that word.
If you look at that part of your query:
select count(*) form Userdata
The word right before Userdata is form, but you should recognise that it's not the keyword from that you intended to write.
Side note (but an important one): The value that you concatentate into the query is not properly escaped, so the code is wide open to SQL injection attacks. You should use a parameter to put the value in the query:
string checkUser = "select count(*) from Userdata where Username = #Username";
SqlCommand cmd = new SqlCommand(checkUser,conn);
cmd.Parameters.AddWithValue("#Username", TextBoxUN.Text);