I'm new to JavaDb/Derby.I'm migrating a project from MySQL to Derby (Project made with JavaFX).I have created an Embedded Db under NetBeans. GUI has Serial Number field (textfield), Name field (textfield), ImageView and TableView (columns with respective data). Below is the java code for connecting with Derby.
public static Connection ConnectionDb() {
try{
String url = "jdbc:derby:Test_JavaDb/webdb;create=true";
String user = "root";
String password = "root";
String driver = "org.apache.derby.jdbc.EmbeddedDriver";
Class.forName(driver).newInstance();
Connection conn = DriverManager.getConnection(url, user, password);
if (conn != null) {
System.out.println("Connected to database #1");
}
return conn;
}catch(Exception e){
JOptionPane.showMessageDialog(null,e);
}
return null;
}
//BELOW METHOD IS LINKED TO A BUTTON FOR LOADING TABLE
#FXML public void LoadTable(){
data.clear();
try{
conn = lrconn.ConnectionDb();
String sql = "select * from TEST";
pst = conn.prepareStatement(sql);
rs = pst.executeQuery();
while(rs.next()){
data.add(new TestPOJO(
rs.getString(1),
rs.getString(2),
rs.getString(3)));
Table.setItems(data);
}
pst.close();
rs.close();
}catch(Exception e1){
}
Table.setOnMouseClicked((MouseEvent me) -> {
try {
conn = lrconn.ConnectionDb();
TestPOJO user = (TestPOJO) Table.getSelectionModel().getSelectedItem();
String sql = "select * from TEST where SLNO =?";
pst = conn.prepareStatement(sql);
pst.setString(1, user.getSLNO());
rs = pst.executeQuery();
while (rs.next()) {
slnoField.setText(rs.getString(1));
nameField.setText(rs.getString(2));
try (InputStream is = rs.getBinaryStream(3)) {
OutputStream os = new FileOutputStream(new File("photo1.jpg"));
byte[] content = new byte[1024];
int size = 0;
while((size= is.read(content))!=-1){
os.write(content,0,size);
}
os.close();
} catch (IOException ex) {
Logger.getLogger(FXMLDocumentController.class.getName()).log(Level.SEVERE, null, ex);
}
image1 = new Image("file:photo1.jpg");
imgvw.setImage(image1);
rs.close();
pst.close();
}catch (SQLException ex) {
Logger.getLogger(FXMLDocumentController.class.getName()).log(Level.SEVERE, null, ex);
}
});
Table.setOnKeyReleased((KeyEvent e) -> {
if(e.getCode()== KeyCode.UP || e.getCode() == KeyCode.DOWN){
try {
TestPOJO user = (TestPOJO) Table.getSelectionModel().getSelectedItem();
String sql = "select * from TEST where SLNO =?";
pst = conn.prepareStatement(sql);
pst.setString(1, user.getSLNO());
rs = pst.executeQuery();
while (rs.next()) {
slnoField.setText(rs.getString(1));
nameField.setText(rs.getString(2));
try (InputStream is = rs.getBinaryStream(3)) {
OutputStream os = new FileOutputStream(new File("photo1.jpg"));
byte[] content = new byte[1024];
int size = 0;
while((size= is.read(content))!=-1){
os.write(content,0,size);
}os.close();
}
image1 = new Image("file:photo1.jpg");
imgvw.setImage(image1);
}}catch (FileNotFoundException ex) {
Logger.getLogger(FXMLDocumentController.class.getName()).log(Level.SEVERE, null, ex);
} catch (IOException | SQLException ex) {
Logger.getLogger(FXMLDocumentController.class.getName()).log(Level.SEVERE, null, ex);
}
}
});
}
The connection works as I get the output "Connected to database #1" on executing code (Clicking on LOAD TABLE BUTTON). But GUI table does not get updated with data from the Embedded Database. Please help.
Related
We have created a code that loops in to CosmosDb records and inserts values to Sql db. But in the process, the data insertion perfomance is very slow. please help with suggestions, here is the code. This process is taking more than 4 hours for inserting a data of 4000 rows.
namespace PushNotificationUserInsert
{
class Program
{
static void Main(string[] args)
{
Task.Run(async () =>
{
#region Variables
var endpoint = ConfigurationManager.AppSettings["DocDbEndpoint"];
var masterKey = ConfigurationManager.AppSettings["DocDbMasterKey"];
var connetionString = ConfigurationManager.AppSettings["SQL_connetionString"].ToString();
// var useremail = "\"\"";
string path = #"xxxx.txt";
string[] useremails = File.ReadAllLines(path);
List<string> It = useremails.ToList();
var newIt = It.Distinct().ToList();
var channel = "\"msteam\"";
var cnn = new SqlConnection(connetionString);
var cnnInsert = new SqlConnection(connetionString);
string query = null;
cnn.Open();
foreach (var email in newIt)
{
query = "SELECT * FROM c where c.document.bot_js.mail = \"" + email + "\" AND CONTAINS(c.id," + channel + ", true)";
dynamic responses = "";
JSONModel.Rootobject records = null;
string conversationId = "";
//string email = "";
#endregion
#region Reading data from SQL
// cnn.Open();
SqlDataReader dataReader;
String Output = "";
SqlCommand command = new SqlCommand(#"SELECT [ConversatonReferenceJson] FROM [dbo].[ConversationReferences] where emailid like ''", cnn);
//command = new SqlCommand(sql, cnn);
dataReader = command.ExecuteReader();
while (dataReader.Read())
{
Output = dataReader.GetValue(0).ToString();
records = JsonConvert.DeserializeObject<JSONModel.Rootobject>(Output);
}
dataReader.Close();
dataReader.Dispose();
#endregion
string[] readText = File.ReadAllLines(path);
//List<string> It = readText.ToList();
//var newIt = It.Distinct().ToList();
//foreach (string email in newIt)
//{
Console.WriteLine(email);
try
{
#region reading data from Consmos DB
using (var client = new DocumentClient(new Uri(endpoint), masterKey))
{
responses = client.CreateDocumentQuery(UriFactory.CreateDocumentCollectionUri("Cosmosdbname", "cosmosdbtablebame"), query).ToList();
}
#endregion
#region Looping throught each cosmos DB records and insert value in SQL
foreach (var response in responses)
{
conversationId = response.id.Remove(0, 26);
records.conversation.id = conversationId;
cnnInsert.Open();
SqlCommand commInsert = new SqlCommand("INSERT INTO [ConversationReferences] VALUES " +
"(#ChannelId, #UserId, #ConverJson, #ID, #EmailID)", cnnInsert);
commInsert.Parameters.AddWithValue("#ChannelId", "xxxx");
commInsert.Parameters.AddWithValue("#UserId", "tobedeleted");
commInsert.Parameters.AddWithValue("#ConverJson", JsonConvert.SerializeObject(records));
commInsert.Parameters.AddWithValue("#ID", "tobedeleted");
commInsert.Parameters.AddWithValue("#EmailID", email);
commInsert.ExecuteNonQuery();
cnnInsert.Close();
Console.WriteLine("records updated for " + email);
}
#endregion
}
catch (Exception ex)
{
cnnInsert.Close();
throw;
}
finally
{ cnnInsert.Close(); }
Console.ReadKey();
}
}).Wait();
}
}
I'm working with two stored procedures in an ASP.NET button function. While I get an error message based on the results that the invoice number is already dispatched from the other stored procedure, it still moves to the other stored procedure and executes it.
If the user gets this error message:
This invoice num was already dispatched!
then it shouldn't move on to this aspect of the function
protected void Button2_Click(object sender, EventArgs e)
{
try
{
for (int i = GridView2.Rows.Count - 1; i >= 0; i--)
{
var row = GridView2.Rows[i];
CheckBox chk = row.FindControl("chkInvoice") as CheckBox;
//CheckBox chk = (CheckBox)GridView2.Rows[i].Cells[0].FindControl("CheckBox3");
if (chk != null && chk.Checked)
{
string strSQLconstring = System.Configuration.ConfigurationManager.ConnectionStrings["TWCL_OPERATIONSConnectionString"].ToString();
using (SqlConnection objConnection = new SqlConnection(strSQLconstring))
{
objConnection.Open();
using (SqlTransaction transaction = objConnection.BeginTransaction())
{
string SID = GridView2.Rows[i].Cells[3].Text.Trim();
SqlDataReader myReader = null;
using (SqlCommand command = new SqlCommand("PP_SelectStatus", objConnection, transaction))
{
command.CommandType = CommandType.StoredProcedure;
command.Parameters.AddWithValue("#invoiceNum", SID);
command.Parameters.AddWithValue("#custPONum", GridView2.Rows[i].Cells[4].Text.Trim());
myReader = command.ExecuteReader();
if (myReader.Read())
{
string invoice1 = (myReader["status"].ToString());
if (invoice1 == "0")
{
ClientScript.RegisterClientScriptBlock(this.GetType(), "alert", "alert('This invoice num was already dispatched!')", true);
}
myReader.Close();
}
}
else if (invoice1=="1")
{
using (SqlCommand cmd = new SqlCommand("PP_RemoveInvoice", objConnection, transaction))
{
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("#loadSheetNum", txtDispatchNum.Text);
cmd.Parameters.AddWithValue("#invoiceNum", SID);
cmd.Parameters.AddWithValue("#removeUser", lblUsername.Text.Replace("Welcome", ""));
**int a = cmd.ExecuteNonQuery();**
cmd.Dispose();
if (a > 0)
{
dt.Rows.RemoveAt(i);
////Read invoice qty from grid view 2
string invoice = GridView2.Rows[i].Cells[5].Text.ToString();
decimal invoiceTotal = Convert.ToDecimal(txtInvoiceTotal.Text) - Convert.ToDecimal(invoice);
txtInvoiceTotal.Text = invoiceTotal.ToString();
////Read invoice weight from grid view 2
string weight = GridView2.Rows[i].Cells[6].Text.ToString();
decimal invoiceWeight = Convert.ToDecimal(txtQtyWeight.Text) - Convert.ToDecimal(weight);
txtQtyWeight.Text = invoiceWeight.ToString();
lblError.ForeColor = Color.Green;
lblError.Text = "Selected record(s) successfully updated";
}
else
{
lblError.ForeColor = Color.Red;
lblError.Text = " Record has not yet been recorded";
}
}
//objConnection.Close();
transaction.Commit();
}
}
}
//Button2.Visible = false;
//showData();
GridView2.DataSource = dt;
GridView2.DataBind();
txtInvoiceCount.Text = dt.Rows.Count.ToString();
}
}
}
catch (Exception ex)
{
if (ex.Message.StartsWith("Violation of PRIMARY KEY constraint"))
{
lblError.ForeColor = Color.Red;
lblError.Text = " This invoice number was remove from dispatch sheet before!!";
}
else
{
// re-throw the error if you haven't handled it
lblError.Text = ex.Message;
throw;
}
}
}
You have a very, very simple logic error, but it is incredibly hard to see because your code is such a mess. Therefore, my answer is:
REFACTOR REFACTOR REFACTOR
It is important to get into the habit of writing short functions and controlling their inputs and outputs. If you don't do this, even a fairly trivial operation like this one gets very confusing and error-prone.
Here is an example of how to organize things. We remove most of the code from the click handler:
protected void DeleteButton_Click(object sender, EventArgs e)
{
for (int i = GridView2.Rows.Count - 1; i >= 0; i--)
{
var row = GridView2.Rows[i];
if (IsChecked(row))
{
var result = ProcessRow(row, i);
DisplayResult(i, result);
}
}
}
Firstly, notice it has a meaningful name. These become very important as your application grows. Also, look how short it is! Where did all the code go? Well, it went into two separate methods, which are now short enough for us to view on one page-- a common requirement that IT organizations impose on their programmers, to avoid spaghetti code.
protected TransactionResult ProcessRow(GridViewRow row, int index)
{
var SID = GridView2.Rows[index].Cells[3].Text.Trim();
var custPONum = GridView2.Rows[index].Cells[4].Text.Trim();
var loadSheetNum = txtDispatchNum.Text;
var removeUser = lblUsername.Text.Replace("Welcome", "");
return ExecuteInvoiceTransaction(SID, custPONum, loadSheetNum, removeUser);
}
And
public void DisplayResult(int rowIndex, TransactionResult result)
{
switch result
{
case TransactionResult.Success:
dt.Rows.RemoveAt(rowIndex);
DisplayTotals(rowIndex);
DisplaySuccess("Selected record(s) successfully updated");
break;
case TransactionResult.AlreadyDispatched;
ClientScript.RegisterClientScriptBlock(this.GetType(), "alert", "alert('This invoice num was already dispatched!')", true);
break;
case TransactionResult.RecordNotRecorded;
DisplayError("Record has not yet been recorded");
break;
case TransactionResult.AlreadyRemoved:
DisplayError("This invoice number was remove from dispatch sheet before!!");
break;
}
}
These methods in turn call a variety of helper methods, each of which does one thing and one thing only. This could be referred to as separation of concerns, which is really important for structured code.
Here's the rest of the methods:
enum TransactionResult
{
Success,
AlreadyDispatched,
RecordNotRecorded,
AlreadyRemoved
}
private bool ExecuteSelectStatus(SqlConnection connection, SqlTransaction transaction, string invoiceNum, string custPONum)
{
using (SqlCommand command = new SqlCommand("PP_SelectStatus", objConnection, transaction))
{
command.CommandType = CommandType.StoredProcedure;
command.Parameters.AddWithValue("#invoiceNum", invoiceNum);
command.Parameters.AddWithValue("#custPONum", custPONum);
using (var myReader = command.ExecuteReader())
{
if (myReader.Read())
{
string invoice1 = (myReader["status"].ToString());
if (invoice1 == "0")
{
return false;
}
}
}
return true;
}
}
private int ExecuteRemoveInvoice(SqlConnection objConnection, SqlTransaction transaction, string loadSheetNum, string invoiceNum, string removeUser)
{
try
{
using (SqlCommand cmd = new SqlCommand("PP_RemoveInvoice", objConnection, transaction))
{
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("#loadSheetNum", loadSheetNum);
cmd.Parameters.AddWithValue("#invoiceNum", invoiceNum);
cmd.Parameters.AddWithValue("#removeUser", removeUser);
return cmd.ExecuteNonQuery();
}
}
catch (SqlException ex)
{
if (ex.Number == 2627) //Primary key violation
{
return -1;
}
}
}
protected TransactionResult ExecuteInvoiceTransaction(string invoiceNum, string custPONum, string loadSheetNum, string removeUser)
{
var strSQLconstring = System.Configuration.ConfigurationManager.ConnectionStrings["TWCL_OPERATIONSConnectionString"].ToString();
using (SqlConnection objConnection = new SqlConnection(strSQLconstring))
{
objConnection.Open();
using (SqlTransaction transaction = objConnection.BeginTransaction())
{
var ok = ExecuteSelectStatus(objConnection, transaction, invoiceNum, custPONum);
if (!ok) return TransactionResult.AlreadyDispatched;
var a = ExecuteRemoveInvoice(objConnection, transaction, loadSheetNum, invoiceNum, removeUser);
switch a
{
case -1:
return TransactionResult.AlreadyRemoved;
case 0:
return TransactionResult.RecordNotRecorded;
default:
transaction.Commit();
return TransactionResult.Success;
}
}
}
}
public void DisplayTotals(int i)
{
////Read invoice qty from grid view 2
string invoice = GridView2.Rows[i].Cells[5].Text;
decimal invoiceTotal = Convert.ToDecimal(txtInvoiceTotal.Text) - Convert.ToDecimal(invoice);
txtInvoiceTotal.Text = invoiceTotal.ToString();
////Read invoice weight from grid view 2
string weight = GridView2.Rows[i].Cells[6].Text();
decimal invoiceWeight = Convert.ToDecimal(txtQtyWeight.Text) - Convert.ToDecimal(weight);
txtQtyWeight.Text = invoiceWeight.ToString();
}
public void DisplaySuccess(string message)
{
lblError.ForeColor = Color.Green;
lblError.Text = message;
}
public void DisplayError(string message)
{
lblError.ForeColor = Color.Red;
lblError.Text = message;
}
A few things to note:
You don't need to call Dispose() if you are using using.
You should always catch the most specific exception possible, per Microsoft's guidance. My example does this.
The exception handling for the primary key error is isolated into the method that calls the stored procedure. The overall business logic shouldn't have to know details about the SQL implementation. I've shown how you can identify the specific error based on this post.
Because there are four possible outcomes, I added an enumeration called TransactionResult so we could return the status to the caller easily.
Some of these methods are short-- just two lines-- and that is OK. The main reason to separate them out is to give them a meaningful name and make the code shorter and easier to read.
This code is much more structured but it could still be improved! In many implementations, the code that accesses the database is actually moved to a completely different layer or project.
See if this works. Moved your if/else together:
protected void Button2_Click(object sender, EventArgs e)
{
try
{
for (int i = GridView2.Rows.Count - 1; i >= 0; i--)
{
var row = GridView2.Rows[i];
CheckBox chk = row.FindControl("chkInvoice") as CheckBox;
if (chk != null && chk.Checked)
{
string strSQLconstring = System.Configuration.ConfigurationManager.ConnectionStrings["TWCL_OPERATIONSConnectionString"].ToString();
using (SqlConnection objConnection = new SqlConnection(strSQLconstring))
{
objConnection.Open();
using (SqlTransaction transaction = objConnection.BeginTransaction())
{
string SID = GridView2.Rows[i].Cells[3].Text.Trim();
SqlDataReader myReader = null;
using (SqlCommand command = new SqlCommand("PP_SelectStatus", objConnection, transaction))
{
command.CommandType = CommandType.StoredProcedure;
command.Parameters.AddWithValue("#invoiceNum", SID);
command.Parameters.AddWithValue("#custPONum", GridView2.Rows[i].Cells[4].Text.Trim());
myReader = command.ExecuteReader();
if (myReader.Read())
{
string invoice1 = (myReader["status"].ToString());
if (invoice1 == "0")
{
ClientScript.RegisterClientScriptBlock(this.GetType(), "alert", "alert('This invoice num was already dispatched!')", true);
}
else if (invoice1 == "1")
{
using (SqlCommand cmd = new SqlCommand("PP_RemoveInvoice", objConnection, transaction))
{
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("#loadSheetNum", txtDispatchNum.Text);
cmd.Parameters.AddWithValue("#invoiceNum", SID);
cmd.Parameters.AddWithValue("#removeUser", lblUsername.Text.Replace("Welcome", ""));
int a = cmd.ExecuteNonQuery();
cmd.Dispose();
if (a > 0)
{
dt.Rows.RemoveAt(i);
////Read invoice qty from grid view 2
string invoice = GridView2.Rows[i].Cells[5].Text.ToString();
decimal invoiceTotal = Convert.ToDecimal(txtInvoiceTotal.Text) - Convert.ToDecimal(invoice);
txtInvoiceTotal.Text = invoiceTotal.ToString();
////Read invoice weight from grid view 2
string weight = GridView2.Rows[i].Cells[6].Text.ToString();
decimal invoiceWeight = Convert.ToDecimal(txtQtyWeight.Text) - Convert.ToDecimal(weight);
txtQtyWeight.Text = invoiceWeight.ToString();
lblError.ForeColor = Color.Green;
lblError.Text = "Selected record(s) successfully updated";
}
else
{
lblError.ForeColor = Color.Red;
lblError.Text = " Record has not yet been recorded";
}
}
//objConnection.Close();
transaction.Commit();
}
}
}
GridView2.DataSource = dt;
GridView2.DataBind();
txtInvoiceCount.Text = dt.Rows.Count.ToString();
}
}
}
}
}
catch (Exception ex)
{
if (ex.Message.StartsWith("Violation of PRIMARY KEY constraint"))
{
lblError.ForeColor = Color.Red;
lblError.Text = " This invoice number was remove from dispatch sheet before!!";
}
else
{
// re-throw the error if you haven't handled it
lblError.Text = ex.Message;
throw;
}
}
}
}
I have an asp.net application in which I have a js file and an ashx file. Here in a download button click Im calling handler file in ajax call and retrieving sql table data in a json formatted string/data table and Im trying to export json formated string/data table to excel/csv file and download it. Please help me to find a solution. (Need a solution which help to export large amount of data and download)
I tried the below code but its not downloading excel file.
public void ProcessRequest(HttpContext context)
{
context.Response.AddHeader("content-disposition", "attachment; filename=FileName.xls");
context.Response.ContentType = "application/csv";
HttpResponse response = context.Response;
string exportContent = ExportToSpreadsheet(JsonStringToDataTable(GetDataFromTable()),'excelfilename');
response.Write(exportContent);
context.Response.End();
}
public DataTable JsonStringToDataTable(string jsonString)
{
DataTable dt = new DataTable();
string[] jsonStringArray = Regex.Split(jsonString.Replace("[", "").Replace("]", ""), "},{");
List<string> ColumnsName = new List<string>();
foreach (string jSA in jsonStringArray)
{
string[] jsonStringData = Regex.Split(jSA.Replace("{", "").Replace("}", ""), ",");
foreach (string ColumnsNameData in jsonStringData)
{
try
{
int idx = ColumnsNameData.IndexOf(":");
string ColumnsNameString = ColumnsNameData.Substring(0, idx - 1).Replace("\"", "");
if (!ColumnsName.Contains(ColumnsNameString))
{
ColumnsName.Add(ColumnsNameString);
}
}
catch (Exception ex)
{
//throw new Exception(string.Format(ex.Message + "Error Parsing Column Name : {0}", ColumnsNameData));
throw ex;
}
}
break;
}
foreach (string AddColumnName in ColumnsName)
{
dt.Columns.Add(AddColumnName);
}
foreach (string jSA in jsonStringArray)
{
string[] RowData = Regex.Split(jSA.Replace("{", "").Replace("}", ""), ",");
DataRow nr = dt.NewRow();
foreach (string rowData in RowData)
{
try
{
int idx = rowData.IndexOf(":");
string RowColumns = rowData.Substring(0, idx - 1).Replace("\"", "");
string RowDataString = rowData.Substring(idx + 1).Replace("\"", "");
nr[RowColumns] = RowDataString;
}
catch (Exception ex)
{
continue;
}
}
dt.Rows.Add(nr);
}
return dt;
}
private static string GetDataFromTable()
{
string returnValue = string.Empty;
var serializer = new JavaScriptSerializer { MaxJsonLength = Int32.MaxValue };
try
{
var result = //get data from sql table;
returnValue = serializer.Serialize(result);
}
catch (Exception e)
{
returnValue = serializer.Serialize(e.Message);
}
return returnValue;
}
public string ExportToSpreadsheet(DataTable table, string name)
{
string res = string.Empty;
try
{
//var resp = Response;
System.Web.HttpResponse resp = System.Web.HttpContext.Current.Response;
resp.Clear();
if (table != null)
{
foreach (DataColumn column in table.Columns)
{
resp.Write(column.ColumnName + ",");
}
}
resp.Write(Environment.NewLine);
if (table != null)
{
foreach (DataRow row in table.Rows)
{
for (int i = 0; i < table.Columns.Count; i++)
{
resp.Write(row[i].ToString().Replace(",", string.Empty) + ",");
}
resp.Write(Environment.NewLine);
}
}
res = "successfully downloaded";
resp.ContentType = "text/csv";
resp.AppendHeader("Content-Disposition", "attachment; filename=" + name + ".csv");
// resp.End();
}
catch(Exception ex)
{
res = ex.Message;
}
return res;
}
Start using a specialized libary like EPPlus. It will create real Excel files.
private void exportToExcel(DataTable dataTable)
{
using (ExcelPackage excelPackage = new ExcelPackage())
{
//create the worksheet
ExcelWorksheet worksheet = excelPackage.Workbook.Worksheets.Add("Sheet 1");
//load the datatable into the sheet, with headers
worksheet.Cells["A1"].LoadFromDataTable(dataTable, true);
//send the file to the browser
byte[] bin = excelPackage.GetAsByteArray();
Response.ClearHeaders();
Response.Clear();
Response.Buffer = true;
Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
Response.AddHeader("content-length", bin.Length.ToString());
Response.AddHeader("content-disposition", "attachment; filename=\"ExcelDemo.xlsx\"");
Response.OutputStream.Write(bin, 0, bin.Length);
Response.Flush();
HttpContext.Current.ApplicationInstance.CompleteRequest();
}
}
I have an application that persists big files with more 2,5 Gb. When client request to download this file, I want that the file goes to the client browser without save on application server as I do today.
I'm using SQL Server 2008 R2, Asp.Net 3.5, and the column that stores the file is of datatype Varbinary.
I went through the same situation and got the solution in this post. You will use the VarbinaryStream class as follows:
Original Post here.
VarbinaryStream filestream = new VarbinaryStream(
DbContext.Database.Connection.ConnectionString,
"FileContents",
"Content",
"ID",
(int)filepost.ID,
true);
Code:
public class VarbinaryStream : Stream
{
private SqlConnection _Connection;
private string _TableName;
private string _BinaryColumn;
private string _KeyColumn;
private int _KeyValue;
private long _Offset;
private SqlDataReader _SQLReader;
private long _SQLReadPosition;
private bool _AllowedToRead = false;
public VarbinaryStream(
string ConnectionString,
string TableName,
string BinaryColumn,
string KeyColumn,
int KeyValue,
bool AllowRead = false)
{
// create own connection with the connection string.
_Connection = new SqlConnection(ConnectionString);
_TableName = TableName;
_BinaryColumn = BinaryColumn;
_KeyColumn = KeyColumn;
_KeyValue = KeyValue;
// only query the database for a result if we are going to be reading, otherwise skip.
_AllowedToRead = AllowRead;
if (_AllowedToRead == true)
{
try
{
if (_Connection.State != ConnectionState.Open)
_Connection.Open();
SqlCommand cmd = new SqlCommand(
#"SELECT TOP 1 [" + _BinaryColumn + #"]
FROM [dbo].[" + _TableName + #"]
WHERE [" + _KeyColumn + "] = #id",
_Connection);
cmd.Parameters.Add(new SqlParameter("#id", _KeyValue));
_SQLReader = cmd.ExecuteReader(
CommandBehavior.SequentialAccess |
CommandBehavior.SingleResult |
CommandBehavior.SingleRow |
CommandBehavior.CloseConnection);
_SQLReader.Read();
}
catch (Exception e)
{
// log errors here
}
}
}
// this method will be called as part of the Stream ímplementation when we try to write to our VarbinaryStream class.
public override void Write(byte[] buffer, int index, int count)
{
try
{
if (_Connection.State != ConnectionState.Open)
_Connection.Open();
if (_Offset == 0)
{
// for the first write we just send the bytes to the Column
SqlCommand cmd = new SqlCommand(
#"UPDATE [dbo].[" + _TableName + #"]
SET [" + _BinaryColumn + #"] = #firstchunk
WHERE [" + _KeyColumn + "] = #id",
_Connection);
cmd.Parameters.Add(new SqlParameter("#firstchunk", buffer));
cmd.Parameters.Add(new SqlParameter("#id", _KeyValue));
cmd.ExecuteNonQuery();
_Offset = count;
}
else
{
// for all updates after the first one we use the TSQL command .WRITE() to append the data in the database
SqlCommand cmd = new SqlCommand(
#"UPDATE [dbo].[" + _TableName + #"]
SET [" + _BinaryColumn + #"].WRITE(#chunk, NULL, #length)
WHERE [" + _KeyColumn + "] = #id",
_Connection);
cmd.Parameters.Add(new SqlParameter("#chunk", buffer));
cmd.Parameters.Add(new SqlParameter("#length", count));
cmd.Parameters.Add(new SqlParameter("#id", _KeyValue));
cmd.ExecuteNonQuery();
_Offset += count;
}
}
catch (Exception e)
{
// log errors here
}
}
// this method will be called as part of the Stream ímplementation when we try to read from our VarbinaryStream class.
public override int Read(byte[] buffer, int offset, int count)
{
try
{
long bytesRead = _SQLReader.GetBytes(0, _SQLReadPosition, buffer, offset, count);
_SQLReadPosition += bytesRead;
return (int)bytesRead;
}
catch (Exception e)
{
// log errors here
}
return -1;
}
public override bool CanRead
{
get { return _AllowedToRead; }
}
#region unimplemented methods
public override bool CanSeek
{
get { return false; }
}
public override bool CanWrite
{
get { return true; }
}
public override void Flush()
{
throw new NotImplementedException();
}
public override long Length
{
get { throw new NotImplementedException(); }
}
public override long Position
{
get
{
throw new NotImplementedException();
}
set
{
throw new NotImplementedException();
}
}
public override long Seek(long offset, SeekOrigin origin)
{
throw new NotImplementedException();
}
public override void SetLength(long value)
{
throw new NotImplementedException();
}
#endregion unimplemented methods
}
After updating my website on ii7 on window server 2008 from framework 3.5 to work with framework 4
i got my c# base database class stop working copmlitly with this error: "Arithmetic operation resulted in an overflow".
I am working with mysql server from different server.
I did not find any solution on this so i had very sadness to role bakce to framework 3.5
here is some of my logs for this error in the event viewr on my server:
Process information:
Process ID: 3680
Process name: w3wp.exe
Account name: NT AUTHORITY\NETWORK SERVICE
Exception information:
Exception type: OverflowException
Exception message: Arithmetic operation resulted in an overflow.
at DataAccess.ExecuteStringQuery(String strSQL) in d:\webSites\s2s\App_Code\DB\DataAccess.cs:line 214
at DataSelect.generalString(String rowName, String tableName, String idName, String ID) in d:\webSites\s2s\App_Code\DB\DataSelect.cs:line 48
at camsBaseShowWeb.OnPreInit(EventArgs e) in d:\webSites\s2s\App_Code\Bases\camsBaseShowWeb.cs:line 134
at System.Web.UI.Page.PerformPreInit()
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
big thanks for any halp
i got this error - no matter wich function i try to call from this code
here is my code:
using System;
using System.Data;
//using Microsoft.Data.Odbc;
using System.Data.Odbc;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
public class DataAccess
{
#region Private Variables
private static DataAccess _DataAccess = null;
private static object _SyncLock = new object();
private string _strCon = "Driver={MySQL ODBC 5.1 Driver};Server=theIP;Database=theDatabase; UID=root;Password=thePassword;Option=3;";
private OdbcConnection myConnection = null;
#endregion
#region Instance Method
public static DataAccess Instance
{
get
{
lock (_SyncLock)
{
if (_DataAccess == null)
_DataAccess = new DataAccess();
return _DataAccess;
}
}
}
#endregion
#region Constractors
public DataAccess()
{
myConnection = new OdbcConnection(_strCon);
myConnection.Open();
}
#endregion
#region Public Functions
public OdbcDataReader ExecuteQueryReader(string strSQL)
{
try
{
OdbcCommand myCommand = new OdbcCommand(strSQL, myConnection);
return myCommand.ExecuteReader();
}
catch (Exception ex)
{
if (Dict.IsRemote == true)
{
sendMail("error ExecuteQueryReader SQL s2s", strSQL, ex);
}
throw ex;
}
}
public DataTable ExecuteQuery(string strSQL)
{
DataTable dt = new DataTable();
OdbcDataAdapter objDataAdapter = null;
try
{
objDataAdapter = new OdbcDataAdapter(strSQL, myConnection);
objDataAdapter.Fill(dt);
}
catch (Exception ex)
{
if (Dict.IsRemote == true)
{
sendMail("error ExecuteQuery SQL s2s", strSQL, ex);
}
throw ex;
}
finally
{
if (objDataAdapter != null) objDataAdapter.Dispose();
}
return dt;
}
public DataView ExecuteQueryDV(string strSQL)
{
DataTable dt = new DataTable();
OdbcDataAdapter objDataAdapter = null;
try
{
objDataAdapter = new OdbcDataAdapter(strSQL, myConnection);
objDataAdapter.Fill(dt);
}
catch (Exception ex)
{
if (Dict.IsRemote == true)
{
sendMail("error ExecuteQuery SQL s2s", strSQL, ex);
}
throw ex;
}
finally
{
if (objDataAdapter != null) objDataAdapter.Dispose();
}
return new DataView(dt);
}
public DataTable ExecuteLimitedQuery(string strSQL, int startRow, int rowNum)
{
DataTable dt;
DataSet ds = new DataSet();
OdbcDataAdapter objDataAdapter = null;
try
{
objDataAdapter = new OdbcDataAdapter(strSQL, myConnection);
objDataAdapter.Fill(ds, startRow, rowNum, "rowTable");
dt = (DataTable)ds.Tables["rowTable"];
}
catch (Exception ex)
{
if (Dict.IsRemote == true)
{
sendMail("error ExecuteLimitedQuery SQL s2s", strSQL, ex);
}
throw ex;
}
finally
{
if (objDataAdapter != null) objDataAdapter.Dispose();
}
return dt;
}
public object ExecuteScalarQuery(string strSQL)
{
OdbcCommand myCommand = null;
object obj = null;
try
{
myCommand = new OdbcCommand(strSQL, myConnection);
obj = myCommand.ExecuteScalar();
}
catch (Exception ex)
{
if (Dict.IsRemote == true)
{
sendMail("error ExecuteScalarQuery SQL s2s", strSQL, ex);
}
throw ex;
}
finally
{
if (myCommand != null) myCommand.Dispose();
}
return obj;
}
public string ExecuteStringQuery(string strSQL)
{
OdbcCommand myCommand = null;
object obj = null;
try
{
myCommand = new OdbcCommand(strSQL, myConnection);
obj = myCommand.ExecuteScalar();
}
catch (Exception ex)
{
if (myConnection.State != ConnectionState.Open)
{
myConnection.Open();
if (myCommand != null) myCommand.Dispose();
try
{
myCommand = new OdbcCommand(strSQL, myConnection);
obj = myCommand.ExecuteScalar();
}
catch (Exception ex2)
{
if (Dict.IsRemote == true)
{
sendMail("error - לאחר ניסיון שני ExecuteStringQuery SQL s2s", strSQL, ex2);
}
throw ex2;
}
}
else
{
if (Dict.IsRemote == true)
{
sendMail("error ExecuteStringQuery SQL s2s", strSQL, ex);
}
throw ex;
}
}
finally
{
if (myCommand != null) myCommand.Dispose();
}
return obj != null ? obj.ToString() : string.Empty;
}
public int ExecuteNoneQuery(string strSQL)
{
OdbcCommand myCommand = null;
int i;
try
{
myCommand = new OdbcCommand(strSQL, myConnection);
i = myCommand.ExecuteNonQuery();
}
catch (Exception ex)
{
if (Dict.IsRemote == true)
{
sendMail("error ExecuteNoneQuery SQL s2s", strSQL, ex);
}
throw ex;
}
finally
{
if (myCommand != null) myCommand.Dispose();
}
return i;
}
public int InsertGetLastID(string strSQL)
{
OdbcCommand myCommand = null;
int LastID = 0;
object objID = null;
try
{
myCommand = new OdbcCommand(strSQL, myConnection);
if (myCommand.ExecuteNonQuery() == 1)
{
myCommand = new OdbcCommand("SELECT LAST_INSERT_ID()", myConnection);
objID = myCommand.ExecuteScalar();
if (objID != null)
{
LastID = int.Parse(objID.ToString());
}
}
}
catch (Exception ex)
{
if (Dict.IsRemote == true)
{
sendMail("error InsertGetLastID SQL s2s", strSQL, ex);
}
throw ex;
}
finally
{
if (myCommand != null) myCommand.Dispose();
}
return LastID;
}
private void sendMail(string title, string sql, Exception ex)
{
string body = string.Empty +
"SQL:\n\n" + sql + "\n\n" +
"Exeption:\n\n" + ex.Message + "\n\n" +
"Stack Trace:\n\n" + ex.StackTrace + "\n\n" +
"Source:\n\n" + ex.Source + "\n\n";
mailSend mailS = new mailSend("theMail", "mailTo", title, body);
}
#endregion
}
I was getting this too since the upgrade to .Net 4.0
System.OverflowException: Arithmetic operation resulted in an overflow.
at System.Data.Odbc.OdbcDataReader.GetSqlType(Int32 i)
at System.Data.Odbc.OdbcDataReader.GetValue(Int32 i)
at System.Data.Odbc.OdbcCommand.ExecuteScalar()
at Server.Engines.MyRunUO.DatabaseCommandQueue.Thread_Start() in d:\RunUO\Sec
ondAge\Scripts\Engines\MyRunUO\DatabaseCommandQueue.cs:line 117
OdbcConnection version is System.Data.dll, v4.0.30319
Using "{MySQL ODBC 5.1 Driver}" (actually 5.01.06.00) against MySQL 5.1.40-community via TCP/IP on localhost.
The query was any variation of:
SELECT COUNT(*) FROM myrunuo_timestamps WHERE time_type='chardb'
The (apparently) offending lines:
command.CommandText = string.Format("SELECT COUNT(*) FROM myrunuo_timestamps WHERE time_type='{0}'", m_timeStampName); // Line 116
object result = command.ExecuteScalar(); // Line 117
This occurred with an x64 compile only, i.e. using the x64 mySQL driver.
This was fixed by upgrading from mySQL ODBC driver 5.01.06.00 to 5.01.08.00
conver to boolean function does not work when
1. Development is done on 32 bit OS
2. Implementation is done on 64 bit OS
When I altered the code for Convert.ToBoolean function, It worked normally.