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• How can I make Access think there is a primary key

  - by user3692757

  I have a table and I'm trying to join it with another table, but it doesn't have a distinctive primary key. The two tables do share similarities, “Acct” and “Location”. If I could concatenate “Acct&Location” it would become a primary key, but Access won’t let me make a primary key from a calculation. I provided a small sample below. Each hospital has an “Acct”, but the “Acct” will show up once for each “Location”. How can I make join these in a relationship? I connected the two in a relationships and tried to “Enforce Referential Integrity”, but it indicated “No unique index found for the referenced field of the primary key”. Also, if I run a “Find UnMatched Query” it doesn’t find anything. I think its because I can’t make it realize that in combination “Acct” and “Location” can be perceived as primary keys when used in conjunction of each other. Acct 1 2 3 1 2 3 1 2 3| Location ABI ABI ABI NHO NHO NHO NTX NTX NTX I tried to load an image to illustrate it better, but I haven't made enough post.

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• How to execute stored procedure from Access using linked tables

  - by webworm

  I have an Access 2003 database that connects to a SQL Server 2008 box via ODBC. The tables from SQL Server are connected as linked tables in Access. I have a stored procedure on the SQL Server that I am trying to execute via ADO code. The problem I have is that Access cannot seem to find the procedure. What do I have to do within Access to be able to execute this stored procedure? Some facts ... The stored procedure in question accepts one parameter which is an integer. The stored procedure returns a recordset which I am hoping to use as the datasource for a ListBox. Here is my ADO code in Access ... Private Sub LoadUserCaseList(userID As Integer) Dim cmd As ADODB.Command Set cmd = New ADODB.Command cmd.ActiveConnection = CurrentProject.Connection cmd.CommandType = adCmdStoredProc cmd.CommandText = "uspGetUserCaseSummaryList" Dim par As New ADODB.Parameter Set par = cmd.CreateParameter("userID", adInteger) cmd.Parameters.Append par cmd.Parameters("userID") = userID Dim rs As ADODB.Recordset Set rs = cmd.Execute() lstUserCases.Recordset = rs End Sub The error I get is "the microsoft jet database engine cannot find the input table or query "uspGetUserCaseSummaryList".

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• Is there a better way to write named-pipes in F#?

  - by Niran

  Hi I am new to F#. I am trying to communicate with java from F# using named pipe. The code below works but I am not sure if there is a better way to do this (I know the infinite loop is a bad idea but this is just a proof of concept) if anyone have any idea to improve this code please post your comments. Thanks in advance Niran open System.IO open System.IO.Pipes exception OuterError of string let continueLooping = true while continueLooping do let pipeServer = new NamedPipeServerStream("testpipe", PipeDirection.InOut, 4) printfn "[F#] NamedPipeServerStream thread created." //wait for connection printfn "[F#] Wait for a client to connect" pipeServer.WaitForConnection() printfn "[F#] Client connected." try // Stream for the request. let sr = new StreamReader(pipeServer) // Stream for the response. let sw = new StreamWriter(pipeServer) sw.AutoFlush <- true; // Read request from the stream. let echo = sr.ReadLine(); printfn "[F#] Request message: %s" echo // Write response to the stream. sw.WriteLine("[F#]: " + echo) pipeServer.Disconnect() with | OuterError(str) -> printfn "[F#]ERROR: %s" str printfn "[F#] Client Closing." pipeServer.Close()

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• Plotting a graph with GD

  - by Nayena

  Here it goes. I have been thinking about this for a long time, and havent really been able to put up a proper way to do it yet. I havent implemented anything yet, as im still designing the thing. The idea is that i crawl a website for internal links, i got this settled, its easy, but after the crawling, i end up with an array with lots of links, and how many times those particular link appears on the site that i crawled (and how they're connected). With this huge array, i want to draw a graph somehow. Assuming i can handle the data correctly, the real question here is how i can draw this in a image by the use of the GD library. I figured if theres less than 12 elements, i can align them up on a unit circle spacing them up as a circle and then connecting them accordingly, so anything up to 12 elements shouldn't be a problem, but if theres more than 12, it could be awesome getting them lined up like this Or well, thats just a rough drawing, but i guess its just to prove a point. So i'm here looking for guidance or tips towards getting the math down to getting the stuff lined up in a good way. I have previously made bar-graphs, so i have little experience doing math with GD. If possible, id prefer not using some plotter-library - in the end, it gives me a better understanding on how things are supposed to be.

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• Getting list of Facebook friends with latest API

  - by Eric

  I'm using the most recent version of the Facebook SDK (which lets to connect to something called the 'graph API' though I'm not sure). I've adapted Facebook's example code to let me connect to Facebook and that works... but I can't get a list of my friends. $friends = $facebook->api('friends.get'); This produces the error message: "Fatal error: Uncaught OAuthException: (#803) Some of the aliases you requested do not exist: friends.get thrown in /mycode/facebook.php on line 543" No clue why that is or what that means. Can someone tell me the right syntax (for the latest Facebook API) to get a list of friends? (I tried "$friends = $facebook-api-friends_get();" and get a different error, "Fatal error: Call to a member function friends_get() on a non-object in /mycode/example.php on line 129".) I can confirm that BEFORE this point in my code, things are fine: I'm connected to Facebook with a valid session and I can get my info and dump it to the screen just... i.e. this code executes perfectly before the failed friends.get call: $session = $facebook->getSession(); if ($session) { $uid = $facebook->getUser(); $me = $facebook->api('/me'); } print_r($me);

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• Any suggestions to improve my PDO connection class?

  - by Scarface

  Hey guys I am pretty new to pdo so I basically just put together a simple connection class using information out of the introductory book I was reading but is this connection efficient? If anyone has any informative suggestions, I would really appreciate it. class PDOConnectionFactory{ public $con = null; // swich database? public $dbType = "mysql"; // connection parameters public $host = "localhost"; public $user = "user"; public $senha = "password"; public $db = "database"; public $persistent = false; // new PDOConnectionFactory( true ) <--- persistent connection // new PDOConnectionFactory() <--- no persistent connection public function PDOConnectionFactory( $persistent=false ){ // it verifies the persistence of the connection if( $persistent != false){ $this->persistent = true; } } public function getConnection(){ try{ $this->con = new PDO($this->dbType.":host=".$this->host.";dbname=".$this->db, $this->user, $this->senha, array( PDO::ATTR_PERSISTENT => $this->persistent ) ); // carried through successfully, it returns connected return $this->con; // in case that an error occurs, it returns the error; }catch ( PDOException $ex ){ echo "We are currently experiencing technical difficulties. We have a bunch of monkies working really hard to fix the problem. Check back soon: ".$ex->getMessage(); } } // close connection public function Close(){ if( $this->con != null ) $this->con = null; } }

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• Avoid slowdowns while using off-site database

  - by Anders Holmström

  The basic layout of my problem is this: Website (ASP.NET/C#) hosted at a dedicated hosting company (location 1) Company database (SQL Server) with records of relevant data (location 2). Location 1 & 2 connected through VPN. Customer visiting the website and wanting to pull data from the company database. No possibility of changing the server locations or layout (i.e. moving the website to an in-office server isn't possible). What I want to do is figure out the best way to handle the data acces in this case, minimizing the need for time-expensive database calls over the VPN. The first idea I'm getting is this: When a user enters the section of the website needing the DB data, you pull all the needed tables from the database into a in-memory dataset. All subsequent views/updates to the data is done on this dataset. When the user leaves (logout, session timeout, browser closed etc) the dataset gets sent to the SQL server. I'm not sure if this is a realistic solution, and it obviously has some problems. If two web visitors are performing updates on the same data, the one finishing up last will have their changes overwriting the first ones. There's also no way of knowing you have the latest data (i.e. if a customer pulls som info on their projects and we update this info while they are viewing them, they won't see these changes PLUS the above overwriting issue will arise). The other solution would be to somehow aggregate database calls and make sure they only happen when you need them, e.g. during data updates but not during data views. But then again the longer a pause between these refreshing DB calls, the bigger a chance that the data view is out of date as per the problem described above. Any input on the above or some fresh ideas would be most welcome.

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• SharePoint Web Part on Masterpage not displaying on SubSite

  - by madatanic

  Hi all, Scenario: - A out-of-the-box DataFormWebPart on masterpage connected to a top-level site List. - A subsite using that same masterpage from top-level site. - Error happens when accessing the sub site as below Stack Trace [InvalidOperationException: Operation is not valid due to the current state of the object.] Microsoft.SharePoint.SPFolder.get_ContentTypeOrder() +488 Microsoft.SharePoint.SPContext.get_ContentTypes() +898 Microsoft.SharePoint.SPContext.get_ContentType() +472 Microsoft.SharePoint.SPContext.get_Fields() +271 Microsoft.SharePoint.WebControls.FormComponent.get_Fields() +44 Microsoft.SharePoint.WebControls.FieldMetadata.get_Field() +419 Microsoft.SharePoint.WebControls.FormField.CreateChildControls() +596 System.Web.UI.Control.EnsureChildControls() +87 Microsoft.SharePoint.WebControls.BaseFieldControl.OnLoad(EventArgs e) +176 System.Web.UI.Control.LoadRecursive() +50 System.Web.UI.Control.LoadRecursive() +141 System.Web.UI.Control.AddedControl(Control control, Int32 index) +265 System.Web.UI.ControlCollection.Add(Control child) +80 System.Web.UI.Control.AddParsedSubObject(Object obj) +41 Microsoft.SharePoint.WebPartPages.WebPart.AddParsedSubObject(Object obj) +1149 Microsoft.SharePoint.WebPartPages.DataFormWebPart.CreateChildControls() +1267 System.Web.UI.Control.EnsureChildControls() +87 System.Web.UI.Control.PreRenderRecursiveInternal() +44 System.Web.UI.WebControls.WebParts.WebPart.PreRenderRecursiveInternal() +42 System.Web.UI.Control.PreRenderRecursiveInternal() +171 System.Web.UI.Control.PreRenderRecursiveInternal() +171 System.Web.UI.Control.PreRenderRecursiveInternal() +171 System.Web.UI.Control.PreRenderRecursiveInternal() +171 System.Web.UI.Control.PreRenderRecursiveInternal() +171 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +842 I have tried the solution from this site to enable the subsite to access top level site list. Is this a bug? Any help would be appreciated.

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• Organising UI code in .NET forms

  - by sb3700

  Hi I'm someone who has taught myself programming, and haven't had any formal training in .NET programming. A while back, I started C# in order to develop a GUI program to control sensors, and the project has blossomed. I was just wondering how best to organise the code, particularly UI code, in my forms. My forms currently are a mess, or at least seem a mess to me. I have a constructor which initialises all the parameters and creates events. I have a giant State property, which updates the Enabled state of all my form control as users progress through the application (ie: disconnected, connected, setup, scanning) controlled by a States enum. I have 3-10 private variables accessed through properties, some of which have side-effects in changing the values of form elements. I have a lot of "UpdateXXX" functions to handle UI elements that depend on other UI elements - ie: if a sensor is changed, then change the baud rate drop down list. They are separated into regions I have a lot of events calling these Update functions I have a background worker which does all the scanning and analysis. My problem is this seems like a mess, particularly the State property, and is getting unmaintainable. Also, my application logic code and UI code are in the same file and to some degree, intermingled which seems wrong and means I need to do a lot of scrolling to find what I need. How do you structure your .net forms? Thanks

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• Problems applying texture to a triangle strip using glTexCoordPointer

  - by Alexey

  Hi, I'm writing a pretty simple piece of code which should draw a plane. The plane must have two different textures on its sides, like if it was a book page. I'm trying to achieve this by doing this: glFrontFace(GL_CCW); glBindTexture(GL_TEXTURE_2D, textures[kActiveSideLeft]); glVertexPointer(3, GL_FLOAT, 0, vertexCoordinates); glTexCoordPointer(2, GL_FLOAT, 0, textureCoordinates); glDrawArrays(GL_TRIANGLE_STRIP, 0, (2 * kHorizontalSegmentsCount + 4) * kVerticalSegmentsCount); glFrontFace(GL_CW); glBindTexture(GL_TEXTURE_2D, textures[kActiveSideRight]); glVertexPointer(3, GL_FLOAT, 0, vertexCoordinates); glTexCoordPointer(2, GL_FLOAT, 0, textureCoordinates); glDrawArrays(GL_TRIANGLE_STRIP, 0, (2 * kHorizontalSegmentsCount + 4) * kVerticalSegmentsCount); textures[] array contains 2 GLuint textures which specify appropriate textures. vertexCoordinates and textureCoordinates contain vertexes and texture coordinates respectively ((2 * kHorizontalSegmentsCount + 4) * kVerticalSegmentsCount) equals 15 and that's exactly how many elements I have in the arrays I set up opengl like this: glEnable(GL_DEPTH_TEST); glClearDepthf(1.0f); glDepthFunc(GL_LEQUAL); glClearColor(0.0, 1.0, 1.0, 1.0); glEnable(GL_TEXTURE_2D); glEnable(GL_CULL_FACE); glCullFace(GL_BACK); glEnableClientState(GL_VERTEX_ARRAY); glEnableClientState(GL_TEXTURE_COORD_ARRAY); glDisableClientState(GL_NORMAL_ARRAY); glDisableClientState(GL_COLOR_ARRAY); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); What happens is when I run it front side of the plane looks Ok, but it appears like if texture coordinates weren't applied to the back side. It appears like texture on the back side is just tiled and not connected to vertexes by any means. Any idea what am I doing wrong? Or any idea about what can I do to debug this problem? Thanks.

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• pyOpenSSL and the WantReadError

  - by directedition

  I have a socket server that I am trying to move over to SSL on python 2.5, but I've run into a snag with pyOpenSSL. I can't find any good tutorials on using it, so I'm operating largely on guesses. Here is how my server sets up the socket: ctx = SSL.Context(SSL.SSLv23_METHOD) ctx.use_privatekey_file ("mykey.pem") ctx.use_certificate_file("mycert.pem") sock = SSL.Connection(ctx, socket.socket(socket.AF_INET, socket.SOCK_STREAM)) sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) addr = ('', int(8081)) sock.bind(addr) sock.listen(5) Here is how it accepts clients: sock.setblocking(0) while True: if len(select([sock], [], [], 0.25)[0]): client_sock, client_addr = sock.accept() client = ClientGen(client_sock) And here is how it sends/receives from the connected sockets: while True: (r, w, e) = select.select([sock], [sock], [], 0.25) if len(r): bytes = sock.recv(1024) if len(w): n_bytes = sock.send(self.message) It's compacted, but you get the general idea. The problem is, once the send/receive loop starts, it dies right away, before anything has been sent or received (that I can see anyway): Traceback (most recent call last): File "ClientGen.py", line 50, in networkLoop n_bytes = sock.send(self.message WantReadError The manual's description of the 'WantReadError' is very vague, saying it can come from just about anywhere. What am I doing wrong?

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• TCP Socket.Connect is generating false positives

  - by Mark

  I'm experiencing really weird behavior with the Socket.Connect method in C#. I am attempting a TCP Socket.Connect to a valid IP but closed port and the method is continuing as if I have successfully connected. When I packet sniffed what was going on I saw that the app was receiving RST packets from the remote machine. Yet from the tracing that is in place it is clear that the connect method is not throwing an exception. Any ideas what might be causing this? The code that is running is basically this IPEndPoint iep = new IPEndPoint(System.Net.IPAddress.Parse(m_ipAddress), m_port); Socket tcpSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); tcpSocket.Connect(iep); To add to the mystery... when running this code in a stand alone console application, the result is as expected – the connect method throws an exception. However, when running it in the Windows Service deployment we have the connect method does not throw an exception. Edit in response to Mystere Man's answer How would the exception be swallowed? I have a Trace.WriteLine right above the .Connect method and a Trace.WriteLine right under it (not shown in the code sample for readability). I know that both traces are running. I also have a try catch around the whole thing which also does a Trace.Writeline and I don't see that in the log files anywhere. I have also enabled the internal socket tracing as you suggested. I don't see any exceptions. I see what appears to be successful connections. I am trying to identify differences between the windows service app and the diagnostic console app I made. I am running out of ideas though End edit Thanks

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• How to programmatically set the text of a cell of database in VB.Net?

  - by manuel

  I have a Microsoft Access database file connected to VB.NET. In the database table, I have a 'No.' and a 'Status' column. Then I have a textbox where I can input an integer. I also have a button, which will change the data cell in 'Status' where 'No.' = txtTitleNo.Text(), when I click it. Let's say I want the 'Status' cell to be changed to "Reserved". What codes should I put in the BtnReserve_Click? Here is the code: Public Class theForm Dim con As New OleDb.OleDbConnection Dim ds As New DataSet Dim daTitles As OleDb.OleDbDataAdapter Private Sub theForm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load con.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=|DataDirectory|\db1.mdb" con.Open() daTitles = New OleDb.OleDbDataAdapter("SELECT * FROM Titles", con) daTitles.Fill(ds, "Titles") DataGridView1.DataSource = ds.Tables("Titles") DataGridView1.AutoResizeColumns() End Sub Private Sub BtnReserve_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnReserve.Click Dim daReserve As OleDb.OleDbCommand For i As Integer = 1 TReservedo DataGridView1.RowCount() If i = Val(txtTitleNo.Text()) Then daReserve = New OleDb.OleDbCommand("UPDATE Titles SET Status = 'Reserved' WHERE No = '" & i & "'", con) daReserve.ExecuteNonQuery() End If Next Dim cb As New OleDb.OleDbCommandBuilder(daTitles) daTitles.Update(ds, "Titles") End Sub This code still does not change the 'Status'. What should I do?

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• How do I make software that preserves database integrity and correctness? Please help, confused.

  - by user287745

  i have made an application project in vs 08 c#, sql server from vs 08. the database has like 20 tables and many fields in each have made an interface for adding deleting editting and retrieving data according to predefined needs of the users. now i have to 1) make to project in to a software which i can deliver to professor. that is he can just double click the icon and the software simply starts. no vs 08 needed to start the debugging 2) the database will be on one powerful computer (dual core latest everything win xp) and the user will access it from another computer connected using LAN i am able to change the connection string to the shared database using vs 08/ debugger whenever the server changes but how am i supposed to do that when its a software? 3)there will by many clients am i supposed to give the same software to every one, so they all can connect to the database, how will the integrity and correctness of the database be maintained? i mean the db.mdf file will be in a folder which will be shared with read and write access. so its not necessary that only one user will write at a time. so is there any coding for this or? please help me out here i am stuck do not know what to do i have no practical experience, would appreciate all the help thank you

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• Javascript function with PHP throwing a "Illegally Formed XML Syntax" error

  - by Joe

  I'm trying to learn some javascript and i'm having trouble figuring out why my code is incorrect (i'm sure i'm doing something wrong lol), but anyways I am trying to create a login page so that when the form is submitted javascript will call a function that checks if the login is in a mysql database and then checks the validity of the password for the user if they exist. however I am getting an error (Illegally Formed XML Syntax) i cannot resolve. I'm really confused, mostly because netbeans is saying it is a xml syntax error and i'm not using xml. here is the code in question: function validateLogin(login){ login.addEventListener("input", function() { $value = login.value; if (<?php //connect to mysql mysql_connect(host, user, pass) or die(mysql_error()); echo("<script type='text/javascript'>"); echo("alert('MYSQL Connected.');"); echo("</script>"); //select db mysql_select_db() or die(mysql_error()); echo("<script type='text/javascript'>"); echo("alert('MYSQL Database Selected.');"); echo("</script>"); //query $result = mysql_query("SELECT * FROM logins") or die(mysql_error()); //check results against given login while($row = mysql_fetch_array($result)){ if($row[login] == $value){ echo("true"); exit(0); } } echo("false"); exit(0); ?>) { login.setCustomValidity("Invalid Login. Please Click 'Register' Below.") } else { login.setCustomValidity("") } }); } the code is in an external js file and the error throws on the last line. Also from reading i understand best practices is to not mix js and php so how would i got about separating them but maintaining the functionality i need? thanks!

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• How to delete a row from a typed dataset and save it to a database?

  - by Zingam

  I am doing this as a small project to learn about disconnected and connected models in .NET 4.0 and SQL Server 2008 R2. I have three tables: Companies (PK CompanyID) Addresses (PK AddressID, FK CompanyID) ContactPersons (PK ContactPersonID, FK CompanyID) CompanyID is assigned manually by the users. The other IDs are auto-generated. Companies has a one-to-many relationship with ContactPerson. I have set any changes to cascade. I display all records in Companies in a DataGridView and when a row is clicked, the corresponding records in ContactPersons are displayed in a second DataGridView. I have successfully implemented updating and inserting new records but I completely fail in my attempts to delete rows and save the changes to the database. I us a typed dataset. If I use this: DataRow[] contactPersonRows = m_SoldaCompaniesFileDataSet.ContactPersons.Select("ContactPersonID = " + this.m_CurrentContactPerson.ContactPersonID); m_SoldaCompaniesFileDataSet.ContactPersons.Rows.Remove(contactPersonRows[0]); The records are displayed properly in the DataGridView but are not saved in the database later. If I use this: DataRow row = m_SoldaCompaniesFileDataSet.ContactPersons.Rows.Find(this.m_CurrentContactPerson.ContactPersonID); row.Delete(); The records are set but I get an exeception: DeletedRowInaccessibleException, when I try to refresh the DataGridView. The exception pop-s up in the auto-generated dataset.design file. I am pretty much stuck at this point since yesterday. I cannot find anything anywhere that remotely resembles my problem. And I cannot understand actually what is going on.

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• MySQL to SQL Server ODBC Connector?

  - by Scott C.

  My boss wants to have data in MySQL DBs used for our website to be "linked and synced" with a Financial Server that has its DB in SQL Server. Sooooo...even though I have no idea how to accomplish this, this just sounds like an absolute nightmare especially since the MySQL DB is most likely going to be hosted in the cloud and not on a machine next to the Financial Server. Any ideas how to accomplish this? (within reason?) Also, his big thing is he wants to basically pull up the data from any record a user enters and using data pulled from that do all sorts of calculations using ANOTHER program that stores its data (apparently) in SQL Server. Thinking of all the data I might have to convert makes me very uneasy. Please tell a ODBC eliminates complicated junk like this. :/ I'm trying to talk him into just having MySQL do a nightly dump into a CSV file or something and using that (rather than connector) to update the SQL Server DBs. I guess I'm just not that comfortable with a server and/or programming I have no say over being connected DIRECTLY to my MySQL DB for the website. If there's no good answer for this, can anyone offer a suggestion as to what I can say to talk him out of this? (I'm a low-level IT guy w/ a decent grasp on programming...but I'm no expert - should I try to push this off to a seasoned IT pro?) Thanks in advance.

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• php script randomly hangs up

  - by sergdev

  I install php 5 (more precisely 5.3.1) as apache module. After this one of my application becomes randomly hang up on mysql_connect - sometimes works, sometimes no, sometimes reload of page helps. How can this be fixed? I use Windows Vista, Apache/2.2.14 (Win32) PHP/5.3.1 with php module, MySql 5.0.67-community-nt. After a minute I obtain the error message: Fatal error: Maximum execution time of 60 seconds exceeded in path\to\mysqlcon.php on line 9 I run MySql locally and heavy load could not be a reason: SHOW PROCESSLIST shows about 3 process SHOW VARIABLES LIKE 'MAX_CONNECTIONS' is 100. UPDATE: At first I thought that this is connected with mysql_connect. But now I can't say for certain. More difficult thing is when I insert the line to debug: $fh = fopen("E://_debugLog", 'a'); fwrite($fh, __FILE__ . " : " . __LINE__ . "\n"); fclose($fh); script start working near that location as a rule.

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• What are the general strategies for the server of an FPS multiplayer game to update its clients?

  - by Hooray Im Helping

  A friend and I were having a discussion about how a FPS server updates the clients connected to it. We watched a video of a guy cheating in Battlefield: Bad Company 2 and saw how it highlighted the position of enemies on the screen and it got us thinking. His contention was that the server only updates the client with information that is immediately relevant to the client. I.e. the server won't send information about enemy players if they are too far away from the client or out of the client's line of sight for reasons of efficiency. He was unsure though - he brought up the example of someone hiding behind a rock, not able to see anyone. If the player were suddenly to pop up where he had three players in his line of sight, there would be a 50ms delay before they were rendered on his screen while the server transmitted the necessary information. My contention was the opposite: that the server sends the client all the information about every player and lets the client sort out what is allowed and what isn't. I figured it would actually be less expensive computationally for the server to just send everything to the client and let the client do the heavy lifting, so to speak. I also figured this is how cheat programs work - they intercept the server packets, get the location of enemies, then show them on the client's view. So the question: What are some general policies or strategies a modern first person shooter server employs to keep its clients updated?

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• How to detect a Socket disconnection?

  - by AngryHacker

  I've implemented a task using the async Sockets pattern in Silverlight 3. I started with Michael Schwarz's implementation and built on top of that. So basically, my Silverlight app establishes a persistent socket connection to a device and then data flows both ways as necessary between the device and the Silverlight app. One thing I am struggling with is how to detect disconnection. I could think of 2 approaches: Keep-Alive. I know this can be done at the Sockets level, but I am not sure how to do this in an async model. How would the Socket class let me know there has been a disconnection. Manual keep alive. Basically, I am having the Silverlight app send a dummy packet every 20 seconds or so. If it fails, I'd assume disconnection. However, incredibly, SocketAsyncEventArgs.SocketError always reports success, even if I simply unplug the device that the Silverlight app is connected to. I am not sure whether this is a bug or what or perhaps I need to upgrade to SL4. Any ideas, direction or implementation would be appreciated.

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• LINQ to SQL - Insert yielding strange behavior.

  - by Isaac

  Hi, I'm trying to insert several newly created items to the database. I have a LINQ2SQL generated class called "Order". Inside order, there's a property called "OrderItems" which is also generated by LINQ2SQL and represents the Items of that Order. So far so good. The problem I'm having right now, is when I try to add more than one newly created OrderItem inside Order. I.E: Order o = orderWorker.GetById( 10 ); for( int i=0; i < 5; ++i ) { OrderItem oi =new OrderItem { Order = order, Price = 100, ShippingPrice = 100, ShippingMethod = ... }; o.OrderItems.Add( oi ); } context.SubmitChanges(); Unfortunately, only a single entity is being added. Yes, I checked the generated SQL by adding Context.Log = Console.Out, and yes, only one statement was created. Any clues? By the way I know I'm not using InsertOnSubmit, by the documentation says: You can explicitly request Inserts by using InsertOnSubmit. Alternatively, LINQ to SQL can infer Inserts by finding objects connected to one of the known objects that must be updated. For example, if you add an Untracked object to an EntitySet(TEntity) or set an EntityRef(TEntity) to an Untracked object, you make the Untracked object reachable by way of tracked objects in the graph. While processing SubmitChanges, LINQ to SQL traverses the tracked objects and discovers any reachable persistent objects that are not tracked. Such objects are candidates for insertion into the database. Thank you very much for your time.

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• Where to store: User connection information?

  - by TomTom

  ;) I am writing a .NET application wher ethe user connects to a given server. ALl information within the application is stored in the server. But I want / need to store the following information for the user: The server he connected to last The username he used to connect last (and no, no password, never ever). Any idea where to store this best? the application config file is not sensible (user != admin, application.config is write protected for him). So, my options are: In the registry. 2 keys under my own subkey. In a sort of ini file, stored in the user's data directory (AppData). This would possibly also allow later expansion (into like saving more information, some of which may not fit into the registry). Anyone a tip? Other alternatives? I tend so far to go for the AppData directory with my own subfolder - simply because it is a nice preparation for later to keep like a local copy of configuration etc.

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• C# Linq to SQL connection string (newbie)

  - by Chris'o

  i am a new linq to sql learner and this is my very first attempt to create a data viewer program. The idea is simple, i'd like to create a software that is able to view content of a table in a database. That's it. I got an early problem here already and i have seen many tutes and articles online but I still cant fix the bug. Here is my code: static void Main(string[] args) { string cs = "Data Source=localhost;Initial Catalog=somedb;Integrated Security=SSPI;"; var db = new DataClasses1DataContext(cs); db.Connection.Open(); foreach (var b in db.Mapping.GetTables()) Console.WriteLine(b.TableName); Console.ReadKey(true); } When I tried to check db.connection.equals(null); it returns false, so i thought i have connected successfully to the database since there is no error at all. But the code above doesn't print anything out to the screen. I kind of lost and don't know what's going on here. Does anyone know what is going wrong here?

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• Using proxy models

  - by smallB

  I've created Proxy model by subclassing QAbstractProxyModel and connected it as a model to my view. I also set up source model for this proxy model. Unfortunately something is wrong because I'm not getting anything displayed on my listView (it works perfectly when I have my model supplied as a model to view but when I supply this proxy model it just doesn't work). Here are some snippets from my code: #ifndef FILES_PROXY_MODEL_H #define FILES_PROXY_MODEL_H #include <QAbstractProxyModel> #include "File_List_Model.h" class File_Proxy_Model: public QAbstractProxyModel { public: explicit File_Proxy_Model(File_List_Model* source_model) { setSourceModel(source_model); } virtual QModelIndex mapFromSource(const QModelIndex & sourceIndex) const { return index(sourceIndex.row(),sourceIndex.column()); } virtual QModelIndex mapToSource(const QModelIndex & proxyIndex) const { return index(proxyIndex.row(),proxyIndex.column()); } virtual int columnCount(const QModelIndex & parent = QModelIndex()) const { return sourceModel()->columnCount(); } virtual int rowCount(const QModelIndex & parent = QModelIndex()) const { return sourceModel()->rowCount(); } virtual QModelIndex index(int row, int column, const QModelIndex & parent = QModelIndex()) const { return createIndex(row,column); } virtual QModelIndex parent(const QModelIndex & index) const { return QModelIndex(); } }; #endif // FILES_PROXY_MODEL_H //and this is a dialog class: Line_Counter::Line_Counter(QWidget *parent) : QDialog(parent), model_(new File_List_Model(this)), proxy_model_(new File_Proxy_Model(model_)), sel_model_(new QItemSelectionModel(proxy_model_,this)) { setupUi(this); setup_mvc_(); } void Line_Counter::setup_mvc_() { listView->setModel(proxy_model_); listView->setSelectionModel(sel_model_); }

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• Getting the full-name of the current user, returns an empty string (C#/C++)

  - by Nir

  I try to get the full-name of the current log-in user (Fullname, not username). The following code C#, C++ works fine but on XP computers not connected to the Net, I get empty string as result if I run it ~20 minutes after login (It runs OK whithin the first ~20 minutes after login) A Win32 API (GetUserNameEx) is used rather that PrincipalContext since it PrincipalContext may takes up to 15 seconds when working offline. Any Help why am I getting an empty string as result though a user full name is specified??? - C# Code public static string CurrentUserFullName { get { const int EXTENDED_NAME_FORMAT_NAME_DISPLAY = 3; StringBuilder userName = new StringBuilder(256); uint length = (uint) userName.Capacity; string ret; if (GetUserNameEx(EXTENDED_NAME_FORMAT_NAME_DISPLAY, userName, ref length)) { ret = userName.ToString(); } else { int errorCode = Marshal.GetLastWin32Error(); throw new Win32Exception("GetUserNameEx Failed. Error code - " + errorCode); } return ret; } } [DllImport("Secur32.dll", CharSet = CharSet.Auto, SetLastError = true)] private static extern bool GetUserNameEx(int nameFormat, StringBuilder lpNameBuffer, ref uint lpnSize); - Code in C++ #include "stdafx.h" #include <windows.h> #define SECURITY_WIN32 #include <Security.h> #pragma comment( lib, "Secur32.lib" ) int _tmain(int argc, _TCHAR* argv[]) { char szName[100]; ULONG nChars = sizeof( szName ); if ( GetUserNameEx( NameDisplay, szName, &nChars ) ) { printf( "Name: %s\n", szName); } else { printf( "Failed to GetUserNameEx\n" ); printf( "%d\n", GetLastError() ); } return 0; }

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