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  • How to create a mysql database that can contain any character, also different languages

    - by Jakke
    I'm trying to create a database that has to contain articles in different languages. I'm using Mariadb as my server and I know bits of SQL. My knowledge doesn't really cover details like the differences between engines like MyISAM, InnoDB etc or character sets like utf8/16/32, latin 5/7/etc. I do know that the character set has importance, I guess what I'm looking for is an all-encompassing character set and an engine that best deals with this type of content. Also, is there an advantage in storing articles in multiple data rows (equivalent of different pages) to make things a little faster, or would you store a whole article in a single data row. Or does that depend on the size of the articles? Sorry for my noobish question, I know the information is all out on the internet but it would take me quite a long time to research and get a grip on everything. Would be cool if someone with experience could give me a little head start and point me in the right direction. This is for a intranet site, consider the content to be somewhat like a blog (and no, I don't want wordpress or something similar at this point). Not sure if it matters, but I tend to create and manipulate my tables with phpmyadmin, I use apache as web server and it all runs on Linux.

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  • Issues with "There is already an object named 'xxx' in the database'

    - by Hoser
    I'm fairly new to SQL so this may be an easy mistake, but I haven't been able to find a solid solution anywhere else. Problem is whenever I try to use my temp table, it tells me it cannot be used because there is already an object with that name. I frequently try switching up the names, and sometimes it'll let me work with the table for a little while, but it never lasts for long. Am I dropping the table incorrectly? Also, I've had people suggest to just use a permanent table, but this database does not allow me to do that. create table #RandomTableName(NameOfObject varchar(50), NameOfCounter varchar(50), SampledValue decimal) select vPerformanceRule.ObjectName, vPerformanceRule.CounterName, Perf.vPerfRaw.SampleValue into #RandomTableName from vPerformanceRule, vPerformanceRuleInstance, Perf.vPerfRaw where (ObjectName like 'Processor' AND CounterName like '% Processor Time') OR(ObjectName like 'System' AND CounterName like 'Processor Queue Length') OR(ObjectName like 'Memory' AND CounterName like 'Pages/Sec') OR(ObjectName like 'Physical Disk' AND CounterName like 'Avg. Disk Queue Length') OR(ObjectName like 'Physical Disk' AND CounterName like 'Avg. Disk sec/Read') OR(ObjectName like 'Physical Disk' and CounterName like '% Disk Time') OR(ObjectName like 'Logical Disk' and CounterName like '% Free Space' AND SampleValue > 70 AND SampleValue < 100) order by ObjectName, SampleValue drop table #RandomTableName

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  • Java RMI (Server: TCP Connection Idle/Client: Unmarshalexception (EOFException))

    - by Perry Dahl Christensen
    I'm trying to implement Sun Tutorials RMI application that calculates Pi. I'm having some serious problems and I cant find the solution eventhough I've been searching the entire web and several javaskilled people. I'm hoping you can put an end to my frustrations. The crazy thing is that I can run the application from the cmd on my desktop computer. Trying the exact same thing with the exact same code in the exact same directories on my laptop produces the following errors. The problem occures when I try to connect the client to the server. I don't believe that the error is due to my policyfile as I can run it on the desktop. It must be elsewhere. Have anyone tried the same and can you give me a hint as to where my problem is, please? POLICYFILE SERVER: grant { permission java.security.AllPermissions; permission java.net.SocketPermission"*", "connect, resolve"; }; POLICYFILE CLIENT: grant { permission java.security.AllPermissions; permission java.net.SocketPermission"*", "connect, resolve"; }; SERVERSIDE ERRORS: Microsoft Windows XP [Version 5.1.2600] (C) Copyright 1985-2001 Microsoft Corp. C:\Documents and Settings\STUDENTcd\ C:start rmiregistry C:java -cp c:\java;c:\java\compute.jar -Djava.rmi.server.codebase=file:/c:/jav a/compute.jar -Djava.rmi.server.hostname=localhost -Djava.security.policy=c:/jav a/servertest.policy engine.ComputeEngine ComputeEngine bound Exception in thread "RMI TCP Connection(idle)" java.security.AccessControlExcept ion: access denied (java.net.SocketPermission 127.0.0.1:1440 accept,resolve) at java.security.AccessControlContext.checkPermission(Unknown Source) at java.security.AccessController.checkPermission(Unknown Source) at java.lang.SecurityManager.checkPermission(Unknown Source) at java.lang.SecurityManager.checkAccept(Unknown Source) at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.checkAcceptPermi ssion(Unknown Source) at sun.rmi.transport.tcp.TCPTransport.checkAcceptPermission(Unknown Sour ce) at sun.rmi.transport.Transport$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at sun.rmi.transport.Transport.serviceCall(Unknown Source) at sun.rmi.transport.tcp.TCPTransport.handleMessages(Unknown Source) at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(Unknown Sou rce) at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(Unknown Sour ce) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source ) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) CLIENTSIDE ERRORS: Microsoft Windows XP [Version 5.1.2600] (C) Copyright 1985-2001 Microsoft Corp. C:\Documents and Settings\STUDENTcd\ C:java -cp c:\java;c:\java\compute.jar -Djava.rmi.server.codebase=file:\C:\jav a\files\ -Djava.security.policy=c:/java/clienttest.policy client.ComputePi local host 45 ComputePi exception: java.rmi.UnmarshalException: Error unmarshaling return header; nested exception is: java.io.EOFException at sun.rmi.transport.StreamRemoteCall.executeCall(Unknown Source) at sun.rmi.server.UnicastRef.invoke(Unknown Source) at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(Unkn own Source) at java.rmi.server.RemoteObjectInvocationHandler.invoke(Unknown Source) at $Proxy0.executeTask(Unknown Source) at client.ComputePi.main(ComputePi.java:18) Caused by: java.io.EOFException at java.io.DataInputStream.readByte(Unknown Source) ... 6 more C: Thanks in advance Perry

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  • Telnet connection using c#

    - by alejandrobog
    Our office currently uses telnet to query an external server. The procedure is something like this. Connect - telnet opent 128........ 25000 Query - we paste the query and then hit alt + 019 Response - We receive the response as text in the telnet window So I’m trying to make this queries automatic using a c# app. My code is the following First the connection. (No exceptions) SocketClient = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); String szIPSelected = txtIPAddress.Text; String szPort = txtPort.Text; int alPort = System.Convert.ToInt16(szPort, 10); System.Net.IPAddress remoteIPAddress = System.Net.IPAddress.Parse(szIPSelected); System.Net.IPEndPoint remoteEndPoint = new System.Net.IPEndPoint(remoteIPAddress, alPort); SocketClient.Connect(remoteEndPoint); Then I send the query (No exceptions) string data ="some query"; byte[] byData = System.Text.Encoding.ASCII.GetBytes(data); SocketClient.Send(byData); Then I try to receive the response byte[] buffer = new byte[10]; Receive(SocketClient, buffer, 0, buffer.Length, 10000); string str = Encoding.ASCII.GetString(buffer, 0, buffer.Length); txtDataRx.Text = str; public static void Receive(Socket socket, byte[] buffer, int offset, int size, int timeout) { int startTickCount = Environment.TickCount; int received = 0; // how many bytes is already received do { if (Environment.TickCount > startTickCount + timeout) throw new Exception("Timeout."); try { received += socket.Receive(buffer, offset + received, size - received, SocketFlags.None); } catch (SocketException ex) { if (ex.SocketErrorCode == SocketError.WouldBlock || ex.SocketErrorCode == SocketError.IOPending || ex.SocketErrorCode == SocketError.NoBufferSpaceAvailable) { // socket buffer is probably empty, wait and try again Thread.Sleep(30); } else throw ex; // any serious error occurr } } while (received < size); } Every time I try to receive the response I get "an exsiting connetion has forcibly closed by the remote host" if open telnet and send the same query I get a response right away Any ideas, or suggestions?

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  • java.net.SocketException: Software caused connection abort: socket write error

    - by npinti
    Hi guys, I am trying to send an image from a Java desktop application to a J2ME application. The problem is that I am getting this exception: java.net.SocketException: Software caused connection abort: socket write error I have looked around on the net, and although this problem is not that rare, I was unable to find a concrete solution. I am transforming the image into a byte array before transferring it. These are the methods found on the desktop application and on the J2ME respectively public void send(String ID, byte[] serverMessage) throws Exception { //Get the IP and Port of the person to which the message is to be sent. String[] connectionDetails = this.userDetails.get(ID).split(","); Socket sock = new Socket(InetAddress.getByName(connectionDetails[0]), Integer.parseInt(connectionDetails[1])); OutputStream os = sock.getOutputStream(); for (int i = 0; i < serverMessage.length; i++) { os.write((int) serverMessage[i]); } os.flush(); os.close(); sock.close(); } private void read(final StreamConnection slaveSock) { Runnable runnable = new Runnable() { public void run() { try { DataInputStream dataInputStream = slaveSock.openDataInputStream(); int inputChar; StringBuffer results = new StringBuffer(); while ( (inputChar = dataInputStream.read()) != -1) { results.append((char) inputChar); } dataInputStream.close(); slaveSock.close(); parseMessage(results.toString()); results = null; } catch(Exception e) { e.printStackTrace(); Alert alertMsg = new Alert("Error", "An error has occured while reading a message from the server:\n" + e.getMessage(), null, AlertType.ERROR); alertMsg.setTimeout(Alert.FOREVER); myDisplay.setCurrent(alertMsg, resultScreen); } } }; new Thread(runnable).start(); } I am sending the message across a LAN, and I have no problems when I send short text messages instead of images. Also, I used wireshark and it seems that the desktop application is only sending part of the message. Any help would be highly appreciated. Also, everything works on the J2ME simulator. Thanks.

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  • Interop.Outlook.UserProperties.Add causing problem during connection time

    - by Akie
    Hi All, I have created a plug-in for outlook. Plug-in has only below code. private void OnNewOutlookInspector(Outlook.Inspector OutlookInsptr) { Outlook.MailItem MlItem = (Outlook.MailItem)OutlookInsptr.CurrentItem; //if I remove below line. Everything is working fine. MlItem.UserProperties.Add("INSPINIT", Outlook.OlUserPropertyType.olText , true , true ).Value = "1"; } public void OnConnection(object application, Extensibility.ext_ConnectMode connectMode, object addInInst, ref System.Array custom) { applicationObject = application; addInInstance = addInInst; MessageBox.Show("in connection new 2"); OutlkApp = (Outlook.Application)application; OutlkInsptrs = OutlkApp.Inspectors; OutlkInsptrs.NewInspector += new Outlook.InspectorsEvents_NewInspectorEventHandler(OnNewOutlookInspector); } Problem I am facing is, When I send HTML mail while plug-in is enabled, receiving end it is being received as a plain text. Below is the mail content along with the header and body at recieving end. x-sender: [email protected] x-receiver: [email protected] Received: from blr-s-07.pointcrossblr.com ([192.168.1.107]) by blr-ws-134.pointcrossblr.com with Microsoft SMTPSVC(6.0.2600.5949); Wed, 22 Dec 2010 17:11:02 +0530 Received: from blrws134 ([192.168.1.175]) by blr-s-07.pointcrossblr.com with Microsoft SMTPSVC(6.0.3790.4675); Wed, 22 Dec 2010 17:11:02 +0530 From: "Ashif Nataliya" <[email protected]> To: <[email protected]> Cc: <[email protected]> Subject: RTF FRM blr to pc.com cc blr-ws-134 Date: Wed, 22 Dec 2010 17:11:02 +0530 Message-ID: <[email protected]> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_NextPart_000_00F7_01CBA1FB.36115580" X-Mailer: Microsoft Outlook 14.0 Content-Language: en-us X-MS-TNEF-Correlator: 00000000DCB2344DE8F50F4FBC91085BB5C06D55A4172000 thread-index: AcuhzRuTOBkvHPUnS1aLi9+cHNAWhA== Return-Path: [email protected] X-OriginalArrivalTime: 22 Dec 2010 11:41:02.0822 (UTC) FILETIME=[1C788860:01CBA1CD] This is a multipart message in MIME format. ------=_NextPart_000_00F7_01CBA1FB.36115580 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit HTML Test Test Mail ------=_NextPart_000_00F7_01CBA1FB.36115580 Content-Type: application/ms-tnef; name="winmail.dat" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="winmail.dat" // and some other code..... Any help is appreciated. Thanks.

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  • Large File Download - Connection With Server Reset

    - by daveywc
    I have an asp.net website that allows the user to download largish files - 30mb to about 60mb. Sometimes the download works fine but often it fails at some varying point before the download finishes with the message saying that the connection with the server was reset. Originally I was simply using Server.TransmitFile but after reading up a bit I am now using the code posted below. I am also setting the Server.ScriptTimeout value to 3600 in the Page_Init event. private void DownloadFile(string fname, bool forceDownload) { string path = MapPath(fname); string name = Path.GetFileName(path); string ext = Path.GetExtension(path); string type = ""; // set known types based on file extension if (ext != null) { switch (ext.ToLower()) { case ".mp3": type = "audio/mpeg"; break; case ".htm": case ".html": type = "text/HTML"; break; case ".txt": type = "text/plain"; break; case ".doc": case ".rtf": type = "Application/msword"; break; } } if (forceDownload) { Response.AppendHeader("content-disposition", "attachment; filename=" + name.Replace(" ", "_")); } if (type != "") { Response.ContentType = type; } else { Response.ContentType = "application/x-msdownload"; } System.IO.Stream iStream = null; // Buffer to read 10K bytes in chunk: byte[] buffer = new Byte[10000]; // Length of the file: int length; // Total bytes to read: long dataToRead; try { // Open the file. iStream = new System.IO.FileStream(path, System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.Read); // Total bytes to read: dataToRead = iStream.Length; //Response.ContentType = "application/octet-stream"; //Response.AddHeader("Content-Disposition", "attachment; filename=" + filename); // Read the bytes. while (dataToRead > 0) { // Verify that the client is connected. if (Response.IsClientConnected) { // Read the data in buffer. length = iStream.Read(buffer, 0, 10000); // Write the data to the current output stream. Response.OutputStream.Write(buffer, 0, length); // Flush the data to the HTML output. Response.Flush(); buffer = new Byte[10000]; dataToRead = dataToRead - length; } else { //prevent infinite loop if user disconnects dataToRead = -1; } } } catch (Exception ex) { // Trap the error, if any. Response.Write("Error : " + ex.Message); } finally { if (iStream != null) { //Close the file. iStream.Close(); } Response.Close(); } }

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  • How can i clear a SQLite database each time i start my app

    - by AndroidUser99
    Hi, i want that each time i start my app my SQLite database get's cleaned for this, i need to make a method on my class MyDBAdapter.java code examples are welcome, i have no idea how to do it this is the dbadapter/helper i'm using: public class MyDbAdapter { private static final String TAG = "NotesDbAdapter"; private DatabaseHelper mDbHelper; private SQLiteDatabase mDb; private static final String DATABASE_NAME = "gpslocdb"; private static final String PERMISSION_TABLE_CREATE = "CREATE TABLE permission ( fk_email1 varchar, fk_email2 varchar, validated tinyint, hour1 time default '08:00:00', hour2 time default '20:00:00', date1 date, date2 date, weekend tinyint default '0', fk_type varchar, PRIMARY KEY (fk_email1,fk_email2))"; private static final String USER_TABLE_CREATE = "CREATE TABLE user ( email varchar, password varchar, fullName varchar, mobilePhone varchar, mobileOperatingSystem varchar, PRIMARY KEY (email))"; private static final int DATABASE_VERSION = 2; private final Context mCtx; private static class DatabaseHelper extends SQLiteOpenHelper { DatabaseHelper(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); } @Override public void onCreate(SQLiteDatabase db) { db.execSQL(PERMISSION_TABLE_CREATE); db.execSQL(USER_TABLE_CREATE); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { db.execSQL("DROP TABLE IF EXISTS user"); db.execSQL("DROP TABLE IF EXISTS permission"); onCreate(db); } } /** * Constructor - takes the context to allow the database to be * opened/created * * @param ctx the Context within which to work */ public MyDbAdapter(Context ctx) { this.mCtx = ctx; } /** * Open the database. If it cannot be opened, try to create a new * instance of the database. If it cannot be created, throw an exception to * signal the failure * * @return this (self reference, allowing this to be chained in an * initialization call) * @throws SQLException if the database could be neither opened or created */ public MyDbAdapter open() throws SQLException { mDbHelper = new DatabaseHelper(mCtx); mDb = mDbHelper.getWritableDatabase(); return this; } public void close() { mDbHelper.close(); } public long createUser(String email, String password, String fullName, String mobilePhone, String mobileOperatingSystem) { ContentValues initialValues = new ContentValues(); initialValues.put("email",email); initialValues.put("password",password); initialValues.put("fullName",fullName); initialValues.put("mobilePhone",mobilePhone); initialValues.put("mobileOperatingSystem",mobileOperatingSystem); return mDb.insert("user", null, initialValues); } public Cursor fetchAllUsers() { return mDb.query("user", new String[] {"email", "password", "fullName", "mobilePhone", "mobileOperatingSystem"}, null, null, null, null, null); } public Cursor fetchUser(String email) throws SQLException { Cursor mCursor = mDb.query(true, "user", new String[] {"email", "password", "fullName", "mobilePhone", "mobileOperatingSystem"} , "email" + "=" + email, null, null, null, null, null); if (mCursor != null) { mCursor.moveToFirst(); } return mCursor; } public List<Friend> retrieveAllUsers() { List <Friend> friends=new ArrayList<Friend>(); Cursor result=fetchAllUsers(); if( result.moveToFirst() ){ do{ //note.getString(note.getColumnIndexOrThrow(NotesDbAdapter.KEY_TITLE))); friends.add(new Friend(result.getString(result.getColumnIndexOrThrow("email")), "","","","")); }while( result.moveToNext() ); } return friends; } }

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  • probelm with recv() on a tcp connection

    - by michael
    Hi, I am simulating TCP communication on windows in C I have sender and a receiver communicating. sender sends packets of specific size to receiver. receiver gets them and send an ACK for each packet it received back to the sender. If the sender didn't get a specific packet (they are numbered in a header inside the packet) it sends the packet again to the receiver. Here is the getPacket function on the receiver side: //get the next packet from the socket. set the packetSize to -1 //if it's the first packet. //return: total bytes read // return: 0 if socket has shutdown on sender side, -1 error, else number of bytes received int getPakcet(char *chunkBuff,int packetSize,SOCKET AcceptSocket){ int totalChunkLen = 0; int bytesRecv=-1; bool firstTime=false; if (packetSize==-1) { packetSize=MAX_PACKET_LENGTH; firstTime=true; } int needToGet=packetSize; do { char* recvBuff; recvBuff = (char*)calloc(needToGet,sizeof(char)); if(recvBuff == NULL){ fprintf(stderr,"Memory allocation problem\n"); return -1; } bytesRecv = recv(AcceptSocket, recvBuff, needToGet, 0); if (bytesRecv == SOCKET_ERROR){ fprintf(stderr,"recv() error %ld.\n", WSAGetLastError()); totalChunkLen=-1; return -1; } if (bytesRecv == 0){ fprintf(stderr,"recv(): socket has shutdown on sender side"); return 0; } else if(bytesRecv > 0) { memcpy(chunkBuff + totalChunkLen,recvBuff,bytesRecv); totalChunkLen+=bytesRecv; } needToGet-=bytesRecv; } while ((totalChunkLen < packetSize) && (!firstTime)); return totalChunkLen; } i use firstTime because for the first time the receiver doesn't know the normal package size that the sender is going to send to it, so i use a MAX_PACKET_LENGTH to get a package and then set the normal package size to the num of bytes i have received my problem is the last package. it's size is less than the package size so lets say last package size is 2 and the normal package size is 4. so recv() gets two bytes, continues to the while condition, then totalChunkLen < packetSize because 2<4 so it iterates the loop again and the gets stuck in recv() because it's blocking because the sender has nothing to send. on the sender side i can't close the connection because i didn't ACK back, so it's kind of a deadlock. receiver is stuck because it's waiting for more packages but sender has nothing to send. i don't want to use a timeout for recv() or to insert a special character to the package header to mark that it is the last one what can i do ? thanks

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  • Doesn't get the output in Java Database Connectivity

    - by Dooree
    I'm working on Java Database Connectivity through Eclipse IDE. I built a database through Ubuntu Terminal, and I need to connect and work with it. However, when I tried to run the following code, I don't get any error, but the following output is showed, anybody knows why I don't get the output from the code ? //STEP 1. Import required packages import java.sql.*; public class FirstExample { // JDBC driver name and database URL static final String JDBC_DRIVER = "com.mysql.jdbc.Driver"; static final String DB_URL = "jdbc:mysql://localhost/EMP"; // Database credentials static final String USER = "username"; static final String PASS = "password"; public static void main(String[] args) { Connection conn = null; Statement stmt = null; try{ //STEP 2: Register JDBC driver Class.forName("com.mysql.jdbc.Driver"); //STEP 3: Open a connection System.out.println("Connecting to database..."); conn = DriverManager.getConnection(DB_URL,USER,PASS); //STEP 4: Execute a query System.out.println("Creating statement..."); stmt = conn.createStatement(); String sql; sql = "SELECT id, first, last, age FROM Employees"; ResultSet rs = stmt.executeQuery(sql); //STEP 5: Extract data from result set while(rs.next()){ //Retrieve by column name int id = rs.getInt("id"); int age = rs.getInt("age"); String first = rs.getString("first"); String last = rs.getString("last"); //Display values System.out.print("ID: " + id); System.out.print(", Age: " + age); System.out.print(", First: " + first); System.out.println(", Last: " + last); } //STEP 6: Clean-up environment rs.close(); stmt.close(); conn.close(); }catch(SQLException se){ //Handle errors for JDBC se.printStackTrace(); }catch(Exception e){ //Handle errors for Class.forName e.printStackTrace(); }finally{ //finally block used to close resources try{ if(stmt!=null) stmt.close(); }catch(SQLException se2){ }// nothing we can do try{ if(conn!=null) conn.close(); }catch(SQLException se){ se.printStackTrace(); }//end finally try }//end try System.out.println("Goodbye!"); }//end main }//end FirstExample <ConnectionProperties> <PropertyCategory name="Connection/Authentication"> <Property name="user" required="No" default="" sortOrder="-2147483647" since="all"> The user to connect as </Property> <Property name="password" required="No" default="" sortOrder="-2147483646" since="all"> The password to use when connecting </Property> <Property name="socketFactory" required="No" default="com.mysql.jdbc.StandardSocketFactory" sortOrder="4" since="3.0.3"> The name of the class that the driver should use for creating socket connections to the server. This class must implement the interface 'com.mysql.jdbc.SocketFactory' and have public no-args constructor. </Property> <Property name="connectTimeout" required="No" default="0" sortOrder="9" since="3.0.1"> Timeout for socket connect (in milliseconds), with 0 being no timeout. Only works on JDK-1.4 or newer. Defaults to '0'. </Property> ...

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  • Persisting objects to a database using a loop

    - by ChaoticLoki
    I have a form that returns multiple values and each value I would like to store in a database, I created a test form for this purpose <form method="post" action="{{ path('submit_exercise', {'page': 1}) }}"> <input type="hidden" name="answers[]" value="Answer 1" "/> <input type="hidden" name="answers[]" value="Answer 2" "/> <input type="hidden" name="answers[]" value="Answer 3" "/> <input type="hidden" name="answers[]" value="Answer 4" "/> <input type="hidden" name="answers[]" value="Answer 5" "/> <input type="hidden" name="answers[]" value="Answer 6" "/> <input type="hidden" name="answers[]" value="Answer 7" "/> <input type="submit" name="submit" /> </form> </body> </html> My submit answers Action is currently written like so. public function submitAnswersAction($page) { //get submitted data $data = $this->get('request')->request->all(); $answers = $data['answers']; //get student ID $user = $this->get('security.context')->getToken()->getUser(); $studentID = $user->getId(); //Get Current time $currentTime = new \DateTime(date("Y-m-d H:m:s")); //var_dump($answers); //var_dump($studentID); //var_dump($currentTime); for($index = 0; $index < count($answers); $index++) { /*echo "Question ". ($index + 1) ."<br />"; echo "Student ID: ". $studentID."<br />"; echo "Page Number: $page <br />"; echo "Answer: $answers[$index]"."<br />"; echo "<br />";*/ $studentAnswer = new StudentAnswer(); $studentAnswer->setStudentID($studentID); $studentAnswer->setPageID($page); $studentAnswer->setQuestionID($index+1); $studentAnswer->setAnswer($answers[$index]); $studentAnswer->setDateCreated($currentTime); $studentAnswer->setReadStatus(0); $database = $this->getDoctrine()->getManager(); $database->persist($studentAnswer); $database->flush(); } return new Response('Answers saved for Student: '.$user->getFullName().' for page: '.$page); When I do a var_dump everything seems to be associated correctly, meaning that the answers array is populated with the right data and so is every other variable, my problem is actually persisting it to the database. when run it returns with this error which seems to me like it doesn't know what variables to put into the row. An exception occurred while executing 'INSERT INTO Student_Answer (student_id, page_id, question_id, answer, read, date_created) VALUES (?, ?, ?, ?, ?, ?)' with params {"1":2,"2":"1","3":1,"4":"Answer 1","5":0,"6":"2012-12-11 12:12:20"}: Any help would be greatly appreciated as this is a personal project to help me try and understand web development a bit more.

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  • TOTD #166: Using NoSQL database in your Java EE 6 Applications on GlassFish - MongoDB for now!

    - by arungupta
    The Java EE 6 platform includes Java Persistence API to work with RDBMS. The JPA specification defines a comprehensive API that includes, but not restricted to, how a database table can be mapped to a POJO and vice versa, provides mechanisms how a PersistenceContext can be injected in a @Stateless bean and then be used for performing different operations on the database table and write typesafe queries. There are several well known advantages of RDBMS but the NoSQL movement has gained traction over past couple of years. The NoSQL databases are not intended to be a replacement for the mainstream RDBMS. As Philosophy of NoSQL explains, NoSQL database was designed for casual use where all the features typically provided by an RDBMS are not required. The name "NoSQL" is more of a category of databases that is more known for what it is not rather than what it is. The basic principles of NoSQL database are: No need to have a pre-defined schema and that makes them a schema-less database. Addition of new properties to existing objects is easy and does not require ALTER TABLE. The unstructured data gives flexibility to change the format of data any time without downtime or reduced service levels. Also there are no joins happening on the server because there is no structure and thus no relation between them. Scalability and performance is more important than the entire set of functionality typically provided by an RDBMS. This set of databases provide eventual consistency and/or transactions restricted to single items but more focus on CRUD. Not be restricted to SQL to access the information stored in the backing database. Designed to scale-out (horizontal) instead of scale-up (vertical). This is important knowing that databases, and everything else as well, is moving into the cloud. RBDMS can scale-out using sharding but requires complex management and not for the faint of heart. Unlike RBDMS which require a separate caching tier, most of the NoSQL databases comes with integrated caching. Designed for less management and simpler data models lead to lower administration as well. There are primarily three types of NoSQL databases: Key-Value stores (e.g. Cassandra and Riak) Document databases (MongoDB or CouchDB) Graph databases (Neo4J) You may think NoSQL is panacea but as I mentioned above they are not meant to replace the mainstream databases and here is why: RDBMS have been around for many years, very stable, and functionally rich. This is something CIOs and CTOs can bet their money on without much worry. There is a reason 98% of Fortune 100 companies run Oracle :-) NoSQL is cutting edge, brings excitement to developers, but enterprises are cautious about them. Commercial databases like Oracle are well supported by the backing enterprises in terms of providing support resources on a global scale. There is a full ecosystem built around these commercial databases providing training, performance tuning, architecture guidance, and everything else. NoSQL is fairly new and typically backed by a single company not able to meet the scale of these big enterprises. NoSQL databases are good for CRUDing operations but business intelligence is extremely important for enterprises to stay competitive. RDBMS provide extensive tooling to generate this data but that was not the original intention of NoSQL databases and is lacking in that area. Generating any meaningful information other than CRUDing require extensive programming. Not suited for complex transactions such as banking systems or other highly transactional applications requiring 2-phase commit. SQL cannot be used with NoSQL databases and writing simple queries can be involving. Enough talking, lets take a look at some code. This blog has published multiple blogs on how to access a RDBMS using JPA in a Java EE 6 application. This Tip Of The Day (TOTD) will show you can use MongoDB (a document-oriented database) with a typical 3-tier Java EE 6 application. Lets get started! The complete source code of this project can be downloaded here. Download MongoDB for your platform from here (1.8.2 as of this writing) and start the server as: arun@ArunUbuntu:~/tools/mongodb-linux-x86_64-1.8.2/bin$./mongod./mongod --help for help and startup optionsSun Jun 26 20:41:11 [initandlisten] MongoDB starting : pid=11210port=27017 dbpath=/data/db/ 64-bit Sun Jun 26 20:41:11 [initandlisten] db version v1.8.2, pdfile version4.5Sun Jun 26 20:41:11 [initandlisten] git version:433bbaa14aaba6860da15bd4de8edf600f56501bSun Jun 26 20:41:11 [initandlisten] build sys info: Linuxbs-linux64.10gen.cc 2.6.21.7-2.ec2.v1.2.fc8xen #1 SMP Fri Nov 2017:48:28 EST 2009 x86_64 BOOST_LIB_VERSION=1_41Sun Jun 26 20:41:11 [initandlisten] waiting for connections on port 27017Sun Jun 26 20:41:11 [websvr] web admin interface listening on port 28017 The default directory for the database is /data/db and needs to be created as: sudo mkdir -p /data/db/sudo chown `id -u` /data/db You can specify a different directory using "--dbpath" option. Refer to Quickstart for your specific platform. Using NetBeans, create a Java EE 6 project and make sure to enable CDI and add JavaServer Faces framework. Download MongoDB Java Driver (2.6.3 of this writing) and add it to the project library by selecting "Properties", "LIbraries", "Add Library...", creating a new library by specifying the location of the JAR file, and adding the library to the created project. Edit the generated "index.xhtml" such that it looks like: <h1>Add a new movie</h1><h:form> Name: <h:inputText value="#{movie.name}" size="20"/><br/> Year: <h:inputText value="#{movie.year}" size="6"/><br/> Language: <h:inputText value="#{movie.language}" size="20"/><br/> <h:commandButton actionListener="#{movieSessionBean.createMovie}" action="show" title="Add" value="submit"/></h:form> This page has a simple HTML form with three text boxes and a submit button. The text boxes take name, year, and language of a movie and the submit button invokes the "createMovie" method of "movieSessionBean" and then render "show.xhtml". Create "show.xhtml" ("New" -> "Other..." -> "Other" -> "XHTML File") such that it looks like: <head> <title><h1>List of movies</h1></title> </head> <body> <h:form> <h:dataTable value="#{movieSessionBean.movies}" var="m" > <h:column><f:facet name="header">Name</f:facet>#{m.name}</h:column> <h:column><f:facet name="header">Year</f:facet>#{m.year}</h:column> <h:column><f:facet name="header">Language</f:facet>#{m.language}</h:column> </h:dataTable> </h:form> This page shows the name, year, and language of all movies stored in the database so far. The list of movies is returned by "movieSessionBean.movies" property. Now create the "Movie" class such that it looks like: import com.mongodb.BasicDBObject;import com.mongodb.BasicDBObject;import com.mongodb.DBObject;import javax.enterprise.inject.Model;import javax.validation.constraints.Size;/** * @author arun */@Modelpublic class Movie { @Size(min=1, max=20) private String name; @Size(min=1, max=20) private String language; private int year; // getters and setters for "name", "year", "language" public BasicDBObject toDBObject() { BasicDBObject doc = new BasicDBObject(); doc.put("name", name); doc.put("year", year); doc.put("language", language); return doc; } public static Movie fromDBObject(DBObject doc) { Movie m = new Movie(); m.name = (String)doc.get("name"); m.year = (int)doc.get("year"); m.language = (String)doc.get("language"); return m; } @Override public String toString() { return name + ", " + year + ", " + language; }} Other than the usual boilerplate code, the key methods here are "toDBObject" and "fromDBObject". These methods provide a conversion from "Movie" -> "DBObject" and vice versa. The "DBObject" is a MongoDB class that comes as part of the mongo-2.6.3.jar file and which we added to our project earlier.  The complete javadoc for 2.6.3 can be seen here. Notice, this class also uses Bean Validation constraints and will be honored by the JSF layer. Finally, create "MovieSessionBean" stateless EJB with all the business logic such that it looks like: package org.glassfish.samples;import com.mongodb.BasicDBObject;import com.mongodb.DB;import com.mongodb.DBCollection;import com.mongodb.DBCursor;import com.mongodb.DBObject;import com.mongodb.Mongo;import java.net.UnknownHostException;import java.util.ArrayList;import java.util.List;import javax.annotation.PostConstruct;import javax.ejb.Stateless;import javax.inject.Inject;import javax.inject.Named;/** * @author arun */@Stateless@Namedpublic class MovieSessionBean { @Inject Movie movie; DBCollection movieColl; @PostConstruct private void initDB() throws UnknownHostException { Mongo m = new Mongo(); DB db = m.getDB("movieDB"); movieColl = db.getCollection("movies"); if (movieColl == null) { movieColl = db.createCollection("movies", null); } } public void createMovie() { BasicDBObject doc = movie.toDBObject(); movieColl.insert(doc); } public List<Movie> getMovies() { List<Movie> movies = new ArrayList(); DBCursor cur = movieColl.find(); System.out.println("getMovies: Found " + cur.size() + " movie(s)"); for (DBObject dbo : cur.toArray()) { movies.add(Movie.fromDBObject(dbo)); } return movies; }} The database is initialized in @PostConstruct. Instead of a working with a database table, NoSQL databases work with a schema-less document. The "Movie" class is the document in our case and stored in the collection "movies". The collection allows us to perform query functions on all movies. The "getMovies" method invokes "find" method on the collection which is equivalent to the SQL query "select * from movies" and then returns a List<Movie>. Also notice that there is no "persistence.xml" in the project. Right-click and run the project to see the output as: Enter some values in the text box and click on enter to see the result as: If you reached here then you've successfully used MongoDB in your Java EE 6 application, congratulations! Some food for thought and further play ... SQL to MongoDB mapping shows mapping between traditional SQL -> Mongo query language. Tutorial shows fun things you can do with MongoDB. Try the interactive online shell  The cookbook provides common ways of using MongoDB In terms of this project, here are some tasks that can be tried: Encapsulate database management in a JPA persistence provider. Is it even worth it because the capabilities are going to be very different ? MongoDB uses "BSonObject" class for JSON representation, add @XmlRootElement on a POJO and how a compatible JSON representation can be generated. This will make the fromXXX and toXXX methods redundant.

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  • Bridging: Loosing WLAN network connection with 4addr on option - Why?

    - by WitchCraft
    Question: For use with my Xen VM, I need to create a virtual network interface (vif) that is bridged to wlan0. If in /etc/network/interfaces I add auto xenbr0 iface xenbr0 inet dhcp And then later do brctl addif xenbr0 wlan0 I get this error message. can't add wlan0 to bridge xenbr0: Operation not supported I found out that Linux won't let you bridge a wireless interface in managed mode at all unless you enable the 4addr option (needed to recompile iw): iw dev wlan0 set 4addr on Afterwards brctl addif xenbr0 wlan0 works, and brctl show shows xenbr0 as bridged to wlan0. Unfortunately, as soon as I execute iw dev wlan0 set 4addr on my entire network connection is gone (no connection). As soon as then I execute iw dev wlan0 set 4addr off I reconnect and it works again. If I re-execute 4addr on, it breaks again, if I execute 4addr off, it works again. Unfortunately, I can't just turn 4addr on, activate the bridge and then turn it back off (error: device not ready). Does anybody know why I loose my connection ?

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  • Why am I getting this error : "ExecuteReader: Connection property has not been initialized." [migrated]

    - by Olga
    I'm trying to read .csv file to import its contents to SQL table I'm getting error: ExecuteReader: Connection property has not been initialized. at the last line of this code: Function ImportData(ByVal FU As FileUpload, ByVal filename As String, ByVal tablename As String) As Boolean Try Dim xConnStr As String = "Driver={Microsoft Text Driver (*.txt; *.csv)};dbq=" & Path.GetDirectoryName(Server.MapPath(filename)) & ";extensions=asc,csv,tab,txt;" ' create your excel connection object using the connection string Dim objXConn As New System.Data.Odbc.OdbcConnection(xConnStr.Trim()) objXConn.Open() Dim objCommand As New OdbcCommand(String.Format("SELECT * FROM " & Path.GetFileName(Server.MapPath(filename)), objXConn)) If objXConn.State = ConnectionState.Closed Then objXConn.Open() Else objXConn.Close() objXConn.Open() End If ' create a DataReader Dim dr As OdbcDataReader dr = objCommand.ExecuteReader()

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  • how to troubleshoot using rsyslog to output to a mysql database

    - by ChrisNZ
    Using FreeBSD 8.0 32 bit. I have installed rsyslogd 5.5.5 with ommysql. (installed ports /usr/ports/sysutils/rsyslog55 and /usr/ports/sysutils/rsyslog55-mysql) My rsyslog.conf file looks like: $ModLoad imudp $ModLoad imtcp $ModLoad ommysql $ModLoad immark.so $ModLoad imuxsock.so $ModLoad imklog.so $OptimizeForUniprocessor on $AllowedSender UDP, 10.0.0.0/8 $UDPServerAddress 0.0.0.0 $UDPServerRun 514 $UDPServerTimeRequery 2 # +SG560 *.* :ommysql:127.0.0.1,Syslog,sysloguser,mypassword My command line flags for rsyslogd are: -c5 -4 Checking the code with -c5 -N1 returns no errors. I have confirmed that rsyslogd is working by changing the last line to say: *.* /var/log/snapgear.log which results in messages appearing in the snapgear.log file. So it is probably something to do with my MySQL setup If I do: mysql -u sysloguser -p Syslog Enter password: Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 56 Server version: 5.0.86 FreeBSD port: mysql-server-5.0.86 mysql> select * from SystemEvents; Empty set (0.00 sec) mysql> :-( I have confirmed that sysloguser has full privileges for the Syslog database. If I run rsyslogd on the console in debug mode: /usr/local/sbin/rsyslogd -f /usr/local/etc/rsyslog.conf -c5 -n -d I can see this sequence of events each time a message is received: 9244.376687256:28359280: main Q: entry added, size now log 1, phys 1 entries 9244.376705694:28359280: main Q: EnqueueMsg advised worker start 9244.376726647:28359280: Listening on UDP syslogd socket 4 (IPv4/port 514). 9244.376728602:28359280: --------imUDP calling select, active file descriptors (max 4): 4 9244.376890075:283593c0: wti 0x28306e80: worker awoke from idle processing 9244.376892031:283593c0: we deleted 0 objects and enqueued 0 objects 9244.376893986:283593c0: delete batch from store, new sizes: log 1, phys 1 9244.376895942:283593c0: msgConsumer processes msg 0/1 9244.376897898:283593c0: msg parser: flags 70, from '~NOTRESOLVED~', msg 'Jun 29 17:32:24 SG560 kernel: (20000629T1732244' 9244.376900132:283593c0: parse using parser list 0x283080e8 (the default list). 9244.376902088:283593c0: dropped LF at very end of message (DropTrailingLF is set) 9244.376904044:283593c0: Parser 'rsyslog.rfc5424' returned -2160 9244.376905999:283593c0: Message will now be parsed by the legacy syslog parser (one size fits all... ;)). 9244.376907955:283593c0: Parser 'rsyslog.rfc3164' returned 0 9244.376909910:283593c0: testing filter, f_pmask 255 9244.376911866:283593c0: Called action, logging to ommysql 9244.376918012:283593c0: actionTryResume: action state: susp, next retry (if applicable): 1277869250 [now 1277869244] 9244.376919967:283593c0: action call returned -2123 9244.376921923:283593c0: tryDoAction: unexpected error code -2123, finalizing 9244.376926113:283593c0: actionTryResume: action state: susp, next retry (if applicable): 1277869250 [now 1277869244] 9244.376928069:283593c0: ruleset: get iRet 0 from rule.ProcessMsg() 9244.376930024:283593c0: ruleset.ProcessMsg() returns 0 9244.376931980:283593c0: regular consumer finished, iret=0, szlog 0 sz phys 1 9244.376933936:283593c0: XXX: enqueueing data element 0 of 1 9244.376935891:283593c0: we deleted 1 objects and enqueued 0 objects 9244.376938126:283593c0: delete batch from store, new sizes: log 0, phys 0 9244.376940082:283593c0: regular consumer finished, iret=4, szlog 0 sz phys 0 9244.376942037:283593c0: main Q:Reg/w0: worker IDLE, waiting for work. .... I can see the Action Call to ommysql returns unexpected error code -2123 Now I am stuck! Any ideas on what to look for next? Perhaps I there are extra ports I need to install? I will be very grateful for any assistance here!

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  • How do I create a WiFi hotspot sharing wireless internet connection (single adapter)?

    - by Ruppesh Nalwaya
    I know how to create a hotspot when connected to a wired network, but when I am using internet from a WiFi connection, this disconnects the wireless connection the moment I activate the hotspot. In Windows I can use Connectify Hotspot, which enables me to share the internet connection from the same wireless adapter as I am creating an access point on. As you can read on the technology overview page: Access Point mode allows you to create a hotspot using the same Wi-Fi card that you are using to access the Internet. How do I do this on Ubuntu?

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  • How to fix: "The connection to the server was reset while the page was loading."?

    - by stupidity
    I have a 64-bit Ubuntu 12.04 installed. I used to login to a website (chess.com) but since a few days ago I get this message: The connection was reset The connection to the server was reset while the page was loading. The site could be temporarily unavailable or too busy. Try again in a few moments. If you are unable to load any pages, check your computer's network connection. If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the Web. This is the case in Firefox, and chrome. A friend of mine confirmed to me that the website is working fine and he could access it. And I can access many other websites and facing no issues except for this website. I tried switching the use TLS 1.0 option as suggested by someone but this didn't fix it. Can someone suggest a way to fix this issue?

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  • How do I sell Oracle? It all starts with the database

    - by swiesner
    Partner sales reps often ask me how they start a conversation with their customers around Oracle. The first question should be, "are you running an Oracle database?" Much of what we do at Oracle is intended to optimize our customers' investments in the Oracle database. Many of our acquisitions, new features in existing products, new applications, are often designed to improve the experience of the 400,000 Oracle database customers worldwide. Once you find an Oracle database customer, the next set of questions are much easier, but depend on your expertise: License Management, Upsell, and Services. Let's start with License Management: Have there been any changes to your infrastructure since you purchased the database licenses? Have you upgraded the servers on which the Oracle database is running? Have the number of users or employees increased since the last license purchase? Yes to any of these questions will lead to investigating correct licensing. The goal is to provide a "soft" license review. Oracle generally does not require any license keys to install our software, so we need to help our customers with compliance. Correct licensing is essential to managing costs, and can provide a great way to efficiently manage IT spend. You might want to contact your local Oracle Channel Manager or VAD for licensing assistance. Or, review the Software Investment Guide. Naturally, these questions can lead to upsell opportunities. If your customer has invested in Oracle technology to manage their data, that data is essential to running their business. We'll take a look at those upsell questions in a later blog post.

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  • Can I monitor traffic on my Incoming Dialup connection using Wireshark?

    - by BeeBand
    Hi, I am trying to create a RAS server in XP Pro. The idea is to log in to this server via a dialup connection. I have set up a new network connection via the New Connect Wizard in XP - according to this tutorial on techrepublic. I am sure that the modem and the connection is working, I have tested it. However, I want to monitor incoming network traffic on this connection. So I thought I would use Wireshark. The problem is that Wireshark does not list this incoming connection on the front page. It lists all my other network connections, ( e.g. my ethernet connection ) but not this one. Whats the best way to monitor traffic on this connection?

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  • How to choose light version of databse system

    - by adopilot
    I am starting one POS (Point of sale) project. Targeting system is going to be written in C# .NET 2 WinForms and as main database server We are going to use MS-SQL Server. As we have a lot of POS devices in chain for one store I will love to have backend local data base system on each POS device. Scenario are following: When main server goes down!! POS application should continue working "off-line" with local database, until connection to main server come up again. Now I am in dilemma which local database is going to be most adoptable for me. Here is some notes for helping me point me in right direction: To be Light "My POS devices art usually old and suffering with performances" To be Free "I have a lot of devices and I do not wont additional cost beside main SQL serer" One day Ill love to try all that port on Mono and Linux OS. Here is what I've researched so far: Simple XML "Light but I am afraid of performance, My main table of items is average of 10K records" SQL-Expres "I am afraid that my POS devices is poor with hardware for SQLExpres, and also hard to install on each device and configure" Less known Advantage Database Server have free distribution of offline ADT system. DBF with extended Library,"Respect for good old DBFs but that era is behind Me with clipper and DBFs" MS Access Sqlite "Mostly like for now, but I am afraid how it is going to pair with MS SQL do they have same Data taypes". I know that in this SO is a lot of subjective data, but at least can someone recommended some others lite database system, or things that I shod most take attention before I choice database.

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  • Hibernate: Check if object exists/changed

    - by swalkner
    Assuming I have an object Person with long id String firstName String lastName String address Then I'm generating a Person-object somewhere in my application. Now I'd like to check if the person exists in the database (= firstname/lastname-combination is in the database). If not = insert it. If yes, check, if the address is the same. If not = update the address. Of course, I can do some requests (first, try to load object with firstname/lastname), then (if existing), compare the address. But isn't there a simpler, cleaner approach? If got several different classes and do not like to have so many queries. I'd like to use annotations as if to say: firstname/lastname = they're the primary key. Check for them if the object exists. address is the parameter you have to compare if it stayed the same or not. Does Hibernate/JPA (or another framework) support something like that? pseude-code: if (database.containsObject(person)) { //containing according to compound keys if (database.containsChangedObject(person)) { database.updateObject(person); } } else { database.insertObject(person); }

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  • 500 internal server error at form connection

    - by klox
    hi..all..i've a problem i can't connect to database what's wrong with my code?this is my code: $("#mod").change(function() { var barcode; barCode=$("#mod").val(); var data=barCode.split(" "); $("#mod").val(data[0]); $("#seri").val(data[1]); var str=data[0]; var matches=str.match(/(EE|[EJU]).*(D)/i); $.ajax({ type:"post", url:"process1.php", data:"value="+matches+"action=tunermatches", cache:false, async:false, success: function(res){ $('#rslt').replaceWith( "<div id='value'><h6>Tuner range is" + res + " .</h6></div>" ); } }); }); and this is my process file: switch(postVar('action')) { case 'tunermatches' : tunermatches(postVar('tuner')); break; function tunermatches($tuner)){ $Tuner=mysql_real_escape_string($tuner); $sql= "SELECT remark FROM settingdata WHERE itemname="Tuner_range" AND itemdata="$Tunermatches"; $res=mysql_query($sql); $dat=mysql_fetch_array($res,MYSQL_NUM); if($dat[0]>0) { echo $dat[0]; } mysql_close($dbc); }

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  • Set service dependencies after install

    - by Dennis
    I have an application that runs as a Windows service. It stores various things settings in a database that are looked up when the service starts. I built the service to support various types of databases (SQL Server, Oracle, MySQL, etc). Often times end users choose to configure the software to use SQL Server (they can simply modify a config file with the connection string and restart the service). The problem is that when their machine boots up, often times SQL Server is started after my service so my service errors out on start up because it can't connect to the database. I know that I can specify dependencies for my service to help guide the Windows service manager to start the appropriate services before mine. However, I don't know what services to depend upon at install time (when my service is registered) since the user can change databases later on. So my question is: is there a way for the user to manually indicate the service dependencies based on the database that they are using? If not, what is the proper design approach that I should be taking? I've thought about trying to do something like wait 30 seconds after my service starts up before connecting to the database but this seems really flaky for various reasons. I've also considered trying to "lazily" connect to the database; the problem is that I need a connection immediately upon start up since the database contains various pieces of vital info that my service needs when it first starts. Any ideas?

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  • Syncing Data to Remote Services, Best Practices for Caching?

    - by viatropos
    I want to be able to publish events to Eventbrite, Eventful, and Google Calendar for my Google Apps. Each service has slightly different properties for events... I will be syncing many other things too, such as users with Google Contacts and MailChimp, Documents with Google Docs and some other services, etc... So I'm wondering, what is the recommended way of retrieving the data for the end user so that it's reasonably maintainable and optimized? Here are the things I'm thinking that I'm having trouble with: My App keeps a central database of all the models (Event, Document, User, Form, etc.), and whenever Admin creates an object (e.g. create through Eventbrite or through our Admin panel), we sync them and store a copy in our local database. When User goes to the site /events, App retrieves the events from the database. Read Events from a target feed, such as the Eventbrite or Eventful feed, and scrap the local database. Basically, I'm wondering, if we're storing all of the data on a remote service, do we really need to have a local database copy of the data? When would we need to have a local database, when wouldn't we?

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  • When does the DataContext will open a connection to the DB?

    - by Eran Betzalel
    I am using L2S to access my MSSQL 2008 Express server. I would like to know when the DataContext will open a connection to the DB? and will it close the connection right after it opened it? For example: var dc = new TestDB(); // connection opened and closed? dc.SomeTable.InsertOnSubmit(obj); // connection opened and closed? foreach(var obj in dc.SomeTable.AsEnumerable()) // connection opened and closed? { ... // connection opened and closed? } dc.SubmitChanges(); // connection opened and closed?

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