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c# odbc update query doesnt work properly

Hi I'm having a lot of truble doing a program in c#
i have to connect to SQLANYWHERE 11 and do an update to a table
could u tell me where I'm wrong?
program go well until i reach the:
int number = wCommand.ExecuteNonQuery(); line
the program doesnt crash but tables get not updated
string dns = "Dsn=dattest;Uid=******;Pwd=******;";
OdbcDataReader reader;
OdbcCommand wCommand;
ODBCClass dst1 = new ODBCClass(dns);
queryins = "UPDATE dba.Sala_export_dati_macchina_produzione SET stato='p'";
// +"WHERE id_prd_lav_ord_lav='"+ id_prd_lav_ord_lav + "'";
wCommand = dst1.GetCommand(queryins);
int number = wCommand.ExecuteNonQuery();
Console.WriteLine("executed "+ number);
this is the odbc class that i'm using
public class ODBCClass
{
OdbcConnection oConnection;
OdbcCommand oCommand;
public ODBCClass(string DataSourceName)
{
oConnection = new OdbcConnection(DataSourceName);
try
{
oConnection.Open();
System.Diagnostics.Trace.WriteLine("Connessione stabilita con il database " + DataSourceName);
}
catch (OdbcException caught)
{
System.Diagnostics.Trace.WriteLine(caught.Message);
}
}
public void CloseConnection()
{
oConnection.Close();
}
public OdbcCommand GetCommand(string Query)
{
oCommand = new OdbcCommand
{
Connection = oConnection,
CommandText = Query
};
return oCommand;
}
public void Dispose()
{
oConnection.Close();
}
}
EDIT
just in case i've tried to change connection string with this pattern:
#"Driver={SQL Anywhere 11};DatabaseName=my_db_name;EngineName=my_server_name;uid=username;pwd=password;LINKs=tcpip(host=host_ip_address)"
and always the system gave me no error on connection in both cases

Ok guys that was kinda strange.
Let me explain the whole thing. I was doing that program for a customer that asked a software which could link my mysql db and a sybase db of another company.
The problem was that the DBMS of that company when is opened on the server block all kind of external editing to the db with which is connected.
So select query worked regularly but update and insert were blocked by that client...
I've passed 4 day with a perfect working program but that company didn't told me this "little" thing.
So be aware of DBMS they are cruel.

Specific if else statement after using a SQL call to retrieve data from a database. Visual Studios 2015 / C#

I'm attempting to add the finishing touch to a project I've been working on and am currently trying to modify a feature that I've created. The feature being that if a student has completed an examination, they are able to view the results. However, what I want to do is create an if else statement that is essentially: if the exam has been taken and completed, then they are redirected to the page that shows them the specific exam's results. Else, it returns a message at the top of the page stating "This examination has not been completed yet."
The current code I have (which is operated through a button on the page) is:
protected void btnViewPrevExam_Click(object sender, EventArgs e)
{
Session["intExaminationID"] = ddlExamination.SelectedValue;
Int32 int32StudentID = Convert.ToInt32(Session["StudentID"]);
Session["int32StudentID"] = Convert.ToInt32(int32StudentID);
// Define the ADO.NET connection object.
SqlConnection objSqlConnection = new SqlConnection(WebConfigurationManager.ConnectionStrings["OPT"].ConnectionString);
// Develop the SQL call.
// Develop the SQL call.
String strSQL = "";
strSQL = "SELECT AnswerID, Question, OptionA, OptionB, OptionC, OptionD, CorrectAnswer, Answer ";
strSQL += " FROM Question, Answer, Examination, Student ";
strSQL += " WHERE Examination.ExaminationID = " + ddlExamination.SelectedValue;
strSQL += " AND Student.StudentID = " + int32StudentID;
strSQL += " AND Answer.QuestionID = Question.QuestionID ";
strSQL += " AND Answer.StudentID = Student.StudentID ";
strSQL += " AND Examination.ExaminationID = Question.ExaminationID ";
// Create the SQL command object.
SqlCommand objSqlCommand = new SqlCommand(strSQL, objSqlConnection);
// Retrieve the row from the table.
objSqlConnection.Open();
SqlDataReader objSqlDataReader = objSqlCommand.ExecuteReader();
objSqlDataReader.Read();
if (strSQL != null)
{
objSqlDataReader.Close();
objSqlConnection.Close();
Response.Redirect("StudentExamResults.aspx");
}
else
{
this.Master.MessageForeColor = System.Drawing.Color.Red;
this.Master.Message = "The selected examination has not been completed.";
}
}
What this button does currently is that it will send the student to the examination results page regardless if the examination has been completed or not. This is due to the line "if (strSQL != null)" and it never being null because the SQL call has been made and filled. I've attempted other ideas, as well as performing a objSqlDataReader for the AnswerID but it didn't work properly. This is a small extra feature I'd like to add to this project that I thought of and would be very pleased if I could find some help on sorting out what I'm doing wrong. Thank you in advance!

Testing if strSQL is not null will always succeed because you are setting it to a non-null value earlier in the method.
To see if a record already exists for a previously-completed examination, you need to check the return value of the call to objSqlDataReader.Read(); it will return true as long as there are additional rows (or, in this case, a first row) to consume from your SELECT query. Thus, change this...
objSqlDataReader.Read();
if (strSQL != null)
{
...to this...
if (objSqlDataReader.Read())
{
As an additional note, consider wrapping objSqlConnection, objSqlCommand, and objSqlDataReader in using blocks to ensure they are properly closed/disposed. As it is now, you are not closing objSqlDataReader and objSqlConnection when the exam needs to be completed, and objSqlCommand is not disposed at all. objSqlDataReader would then be closed as follows, regardless of which branch of the if is taken...
using (SqlDataReader objSqlDataReader = objSqlCommand.ExecuteReader())
{
if (objSqlDataReader.Read())
{
//objSqlDataReader.Close();// No longer necessary - handled by using
objSqlConnection.Close();
Response.Redirect("StudentExamResults.aspx");
}
else
{
this.Master.MessageForeColor = System.Drawing.Color.Red;
this.Master.Message = "The selected examination has not been completed.";
}
}

Assuming you don't care about the contents, rather you just want to check if the row exists, you can do something like this:
string sql = "SELECT COUNT(AnswerID) FROM Question ........ WHERE ......";
using (var connection = CreateConnection()) {
using (var cmd = new SqlCommand(sql, connection)) {
bool exists = (int) cmd.ExecuteScalar() > 0;
if (exists) {
Response.Redirect("StudentExamResults.aspx");
} else {
// Do the other thing
}
}
}

Timeout Expired - Session - How to Fix

Hi all and thanks in advance. I am trying to fix a method that inserts information to a database table. Currently its experiencing timeouts because its running in a while loop that is taking too long to process all the contents. While I know I could just increase the command timeout I don't think that solves the problem because I think its the code. But I'm not certain what the correct fix is. I have access to Dapper and I wonder if it would be more efficient to make a method that passes the necessary variables and executes just a quick simple statement for that group then goes to get the next one? Or is that just perpetuating what's below just in a different way? Should I move this out of the code and onto the server for better performance?
UPDATE Full error message:
Exception of type 'System.Web.HttpUnhandledException' was thrown.
File: c:\WINDOWS\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\6caa4c91\19b853c6\App_Web_o3102kpb.9.cs
Method: ProcessRequest Line Number : 0
Inner Exception: {Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.
File: z:\inetpub\wwwroot\SessionTransfer.aspx.cs
Method: AddSessionToDatabase Line Number : 94
Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.
File: z:\inetpub\wwwroot\SessionTransfer.aspx.cs Method: Page_Load Line Number : 33 }
Here is the original code:
SqlConnection con = new SqlConnection(connectionString);
SqlCommand cmd = new SqlCommand();
con.Open();
cmd.Connection = con;
int i = 0;
string strSql, guid = GetGuid();
string temp = "";
while (i < Session.Contents.Count)
{
if (Session.Contents[i] == null)
temp = "";
else {
if ((Session.Contents[i].ToString().Trim().Length) > 0)
temp = Session.Contents[i].ToString().Replace("'", "''");
else
temp = "";
}
strSql = "INSERT INTO SessionTable (GUID, SessionKey, SessionValue) " +
"VALUES ('" + guid + "', '" + Session.Contents.Keys[i].ToString() + "', '" + temp + "')";
cmd.CommandText = strSql;
cmd.ExecuteNonQuery();
i++;
}
con.Close();
cmd.Dispose();
con.Dispose();
return guid;
UPDATE - FINAL SOLUTION:
var SessionList = new List<Session>();
while (i < Session.Contents.Count)
{
string temp = "";
if (Session.Contents[i] == null)
temp = "";
else
{
temp = (Session.Contents[i].ToString().Trim().Length) > 0 ? Session.Contents[i].ToString().Replace("'", "''") : "";
}
var s = new Session
{
TempGuid = guidTemp,
Contents = Session.Contents[i] != null ? Session.Contents[i].ToString() : null,
Temp = temp
};
SessionList.Add(s);
i++;
}
mySession = SerializationUtilities.SerializeObjectToXML(SessionList);
using (var con = new SqlConnection())
{
con.ExecuteHGW("Transfer", new { mySession }, commandType: CommandType.StoredProcedure);
}
Then on the SQL side I just put the XML in a table and did one single insert statement against the table, time is significantly improved.

I would like to suggest you 2 improvements:
in the loop you are executing insert statements one by one against db. It takes much time to open connection to db then send the query, execute it and return result. It is much better to batch them. So gather like 10,000 of such insert statements, build the whole instuction with StringBuilder and execute it against db in one go. This will really increase the speed of your app. Amount of Insert instructions in one batch you should choose yourself basing on system tests.
If after applying 1) hint the problem with timeout still occurs I would suggest 2 possible solutions:
a). do not send all elements to be processed against db to web service at once but instead, as previoulsy, batch them (apply second batching). So for instance send to web service 50,000 elements to be insterted, then wait for confirmation from web service and then proceed with next batch. The big advantage is that you can show to user easily progress bar showing him current operation state.
b). send all items to be processed against db at once but do not wait for result. In your app just show that items are processed and each 10 s send to web service request to ask if the job is finished. When it is finished signal it to user.

Getting timeout errors with SqlTransaction on same table

public TransImport()
{
ConnString = ConfigurationManager.ConnectionStrings["Connection"].ConnectionString;
SqlConnection conn_new;
SqlCommand command_serial_new;
SqlConnection conn;
SqlCommand command_serial;
SqlTransaction InsertUpdateSerialNumbers;
conn = new SqlConnection(ConnString);
command_serial = conn.CreateCommand();
conn_new = new SqlConnection(ConnString);
command_serial_new = conn_new.CreateCommand();
command_serial_new.CommandText = "SELECT 1 FROM YSL00 WHERE SERLNMBR = #slnr";
var p = new SqlParameter("#slnr", SqlDbType.NVarChar, 50);
command_serial_new.Parameters.Add(p);
//Here you will start reading flat file to get serialnumber.
InsertUpdateSerialNumbers = conn.BeginTransaction();
while (!headerFileReader.EndOfStream)
{
headerRow = headerFileReader.ReadLine();
if (CheckSerialNumber(headerFields[0].Trim()))
DisplayMessage("Good serialnumber"); //this function is not copied here.
}
InsertUpdateSerialNumbers.Commit();
}
private Boolean CheckSerialNumber(string SerialNumber)
{
command_serial_new.Parameters["#slnr"].Value = SerialNumber;
try
{
var itExists = Convert.ToInt32(command_serial_new.ExecuteScalar()) > 0;
if (!itExists)
{
command_serial.Transaction = InsertUpdateSerialNumbers;
command_serial.CommandText = "INSERT INTO YSL00([Manifest_Number],[PONUMBER],[ITEMNMBR],[SERLNMBR]"
+ "VALUES ('" + Manifest + "','" + PONr + "','" + itemNumber + "','" + serialNr + "')";
var insertStatus = command_serial.ExecuteNonQuery();
return true;
}
}
catch (Exception ex)
{
LogException(ex, "Error in CheckSerialNumber =>"+ command_serial_new.CommandText.ToString());
}
return false;
}
I get error "Timeout expired. The timeout period elapsed prior to completion of the operation or server is not responding".
The CheckSerialNumber function also does an insert to YSL00 (the same table where I had executescalar. See code above).
As I mentioned earlier there are 1000s of line in a flat file that I read and update YSL000 table.
Note that I have two separate sqlcommands and also two separate connections to handle this. Reason is with sqltransaction it doesn't let me to query on the same table. I think timeout may be happening because of this?
Thanks for reading. Please suggest
Update 1: Since I have not pasted entire code, I want to mention that dispose is done using below code in the program.
if (conn != null)
{
conn.Close();
conn.Dispose();
}
if (conn_new != null)
{
conn_new.Close();
conn_new.Dispose();
}

you can increase the time out of your SqlConnection object.
you can do this with your ConnString:
string connStr = "Data Source=(local);Initial Catalog=AdventureWorks;Integrated
Security=SSPI;Connection Timeout=300";

I think default isolation level - read commited - is preventing your 'CheckSerialNumber' method from being effective. Command_serial_new will not take into consideration rows inserted in your loop - this might lead to some troubles. To be honest I would also look for some deadlock. Perhaps command_serial_new is actually completely blocked by the other transaction.
To start off:
Set command_serial_new query as:
SELECT 1 FROM YSL00 WITH (NOLOCK) WHERE SERLNMBR = #slnr
Think about using lower isolation level to query inserted rows as well (set it to read uncommited).
Close your connections and transactions.
Use just one SqlConnection - you don't need two of them.

Many of the objects you are using implement IDisposable, and you should be wrapping them with using statements. Without these using statements, .NET won't necessarily get rid of your objects until an undetermined time when the garbage collector runs, and could block subsequent queries if it's still holding a transaction open somewhere.
So for example, you'll need to wrap your connections with using statements:
using (conn_new = new SqlConnection(ConnString)) {
...

If I am not mistaken you need to merge the file content with the table content.
For this purpose I would recommend you
Copy the file content in to a temporary table (see temporary tables and BulkInsert)
Use command MERGE (http://msdn.microsoft.com/en-us/library/bb510625.aspx) to merge the temporary table content with the original table

Can someone help me with some beginners JDBC?

As a C# developer new to Java, i thought it might be easiest if i simply show a bit of C# code so i can see what the equivalent Java JDBC calls are:
String myConnectionString = "...";
String mySql = "select name from people where id = #myId";
int myId = 123456;
List<Field> fields = new List<Field>();
using (SqlConnection conn = new SqlConnection(myConnectionString)
{
conn.Open();
using (SqlCommand cmd = new SqlCommand(mySql,conn))
{
cmd.Parameters.AddWithValue("#myId", myId);
using(SqlDataReader rdr = cmd.ExecuteReader())
{
while (rdr.Read())
{
String name = rdr.GetString(0);
fields.Add(name);
}
}
}
}
Now i know that the using statements above will safely close the database if anything goes wrong, whereas with java it's a bit more complicated (try..finally or something). And in java, i'm not sure what exactly needs to be disposed or closed (or whatever) - the connection only? Or the statement as well?
If you could give me a leg up, that'd be great. Thanks a lot
edit: I really like the code here: (Java Exception Handling - Style)
Connection conn = MyDatabaseLayer.getConnection();
try {
... use conn ...
}
finally {
conn.close();
}
However, do i need to do any further exception handling to ensure the statement and reader and all that other stuff gets closed? Or is closing the connection enough?

Here's a rough explanation of the steps, as liberally copied from some random page:
first, you load the driver. This will be a class in your driver jar file. In many environments you get this, actually, from a datasource, this is sort of old fashioned, but probably better to see the nuts and bolts.
Class.forName("com.imaginary.sql.msql.MsqlDriver");
then you get a connection:
Connection conn = DriverManager.getConnection("jdbc:msql://www.myserver.com:1114/....", "user1", "password");
The url string tends to be different for different db vendors. Luckily we don't swap databases too often, so you only need to look it up once. Now you can finally use the damned thing.
PreparedStatement ps = conn.prepareStatement("SELECT * FROM FOO WHERE A=?", 1);
A prepared statement gets cached, so you can use it with inseted parameters. It will work with a plain SQL statement, but for that you can just use a statement. You can also just call conn.executeQuery(...) to get a resultSet, which is what you want.
ResultSet rs = ps.executeQuery();
Now you can loop through the rs, and get whatever:
while (rs.next())
{
..
}
ResultSets also have ResultSetmetadata which gives you things like the column names, # of columns (but not the total # of results, which would be too easy).
As for try catch, you need to close your statement/result set after you use them. Every time. Otherwise bad things will happen. Like leaving open resources on your db. Since your db connect method can throw errors, you rap the whole thing in a try catch, and close your statement (and connection, if you've made it here) in a finally block.
This is why people use ORM frameworks in java.

You indeed need a try-finally block here. The Java equivalent of the using keyword will be introduced in the upcoming Java 7. A Java port of your code would look like:
// Prepare.
String url = "...";
String sql = "SELECT name FROM people WHERE id = ?";
int id = 123456;
List<String> names = new ArrayList<String>();
// Declare before try.
Connection connection = null;
PreparedStatement statement = null;
ResultSet resultSet = null;
try {
// Acquire inside try.
connection = DriverManager.getConnection(url);
statement = connection.prepareStatement(sql);
statement.setInt(1, id);
resultSet = statement.executeQuery();
// Process results.
while (resultSet.next()) {
names.add(resultSet.getString("name"));
}
} finally {
// Close in reversed order in finally.
if (resultSet != null) try { resultSet.close(); } catch (SQLException logOrIgnore) {}
if (statement != null) try { statement.close(); } catch (SQLException logOrIgnore) {}
if (connection != null) try { connection.close(); } catch (SQLException logOrIgnore) {}
}
When not using connection pooling, closing the Connection alone would in most cases also close the Statement and ResultSet. Although not strictly specified in the JDBC API, the average JDBC driver would implicitly do that. But this is not the normal JDBC idiom. You should really close all the resources explicitly. This makes your code safely reusable for the case that you'd like to introduce connection pooling.
See also:
Equivalent of "using" keyword in Java
JDBC tutorial
JDBC connection pooling practices
JDBC connectivity with MySQL