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  • Ado.net Fill method not throwing error on running a Stored Procedure that does not exist.

    - by Mike
    I am using a combination of the Enterprise library and the original Fill method of ADO. This is because I need to open and close the command connection myself as I am capture the event Info Message Here is my code so far // Set Up Command SqlDatabase db = new SqlDatabase(ConfigurationManager.ConnectionStrings[ConnectionName].ConnectionString); SqlCommand command = db.GetStoredProcCommand(StoredProcName) as SqlCommand; command.Connection = db.CreateConnection() as SqlConnection; // Set Up Events for Logging command.StatementCompleted += new StatementCompletedEventHandler(command_StatementCompleted); command.Connection.FireInfoMessageEventOnUserErrors = true; command.Connection.InfoMessage += new SqlInfoMessageEventHandler(Connection_InfoMessage); // Add Parameters foreach (Parameter parameter in Parameters) { db.AddInParameter(command, parameter.Name, (System.Data.DbType)Enum.Parse(typeof(System.Data.DbType), parameter.Type), parameter.Value); } // Use the Old Style fill to keep the connection Open througout the population // and manage the Statement Complete and InfoMessage events SqlDataAdapter da = new SqlDataAdapter(command); DataSet ds = new DataSet(); // Open Connection command.Connection.Open(); // Populate da.Fill(ds); // Dispose of the adapter if (da != null) { da.Dispose(); } // If you do not explicitly close the connection here, it will leak! if (command.Connection.State == ConnectionState.Open) { command.Connection.Close(); } ... Now if I pass into the variable StoredProcName = "ThisProcDoesNotExists" And run this peice of code. The CreateCommand nor da.Fill through an error message. Why is this. The only way I can tell it did not run was that it returns a dataset with 0 tables in it. But when investigating the error it is not appearant that the procedure does not exist. EDIT Upon further investigation command.Connection.FireInfoMessageEventOnUserErrors = true; is causeing the error to be surpressed into the InfoMessage Event From BOL When you set FireInfoMessageEventOnUserErrors to true, errors that were previously treated as exceptions are now handled as InfoMessage events. All events fire immediately and are handled by the event handler. If is FireInfoMessageEventOnUserErrors is set to false, then InfoMessage events are handled at the end of the procedure. What I want is each print statement from Sql to create a new log record. Setting this property to false combines it as one big string. So if I leave the property set to true, now the question is can I discern a print message from an Error ANOTHER EDIT So now I have the code so that the flag is set to true and checking the error number in the method void Connection_InfoMessage(object sender, SqlInfoMessageEventArgs e) { // These are not really errors unless the Number >0 // if Number = 0 that is a print message foreach (SqlError sql in e.Errors) { if (sql.Number == 0) { Logger.WriteInfo("Sql Message",sql.Message); } else { // Whatever this was it was an error throw new DataException(String.Format("Message={0},Line={1},Number={2},State{3}", sql.Message, sql.LineNumber, sql.Number, sql.State)); } } } The issue now that when I throw the error it does not bubble up to the statement that made the call or even the error handler that is above that. It just bombs out on that line The populate looks like // Populate try { da.Fill(ds); } catch (Exception e) { throw new Exception(e.Message, e); } Now even though I see the calling codes and methods still in the Call Stack, this exception does not seem to bubble up?

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  • How can I get SQL Server transactions to use record-level locks?

    - by Joe White
    We have an application that was originally written as a desktop app, lo these many years ago. It starts a transaction whenever you open an edit screen, and commits if you click OK, or rolls back if you click Cancel. This worked okay for a desktop app, but now we're trying to move to ADO.NET and SQL Server, and the long-running transactions are problematic. I found that we'll have a problem when multiple users are all trying to edit (different subsets of) the same table at the same time. In our old database, each user's transaction would acquire record-level locks to every record they modified during their transaction; since different users were editing different records, everyone gets their own locks and everything works. But in SQL Server, as soon as one user edits a record inside a transaction, SQL Server appears to get a lock on the entire table. When a second user tries to edit a different record in the same table, the second user's app simply locks up, because the SqlConnection blocks until the first user either commits or rolls back. I'm aware that long-running transactions are bad, and I know that the best solution would be to change these screens so that they no longer keep transactions open for a long time. But since that would mean some invasive and risky changes, I also want to research whether there's a way to get this code up and running as-is, just so I know what my options are. How can I get two different users' transactions in SQL Server to lock individual records instead of the entire table? Here's a quick-and-dirty console app that illustrates the issue. I've created a database called "test1", with one table called "Values" that just has ID (int) and Value (nvarchar) columns. If you run the app, it asks for an ID to modify, starts a transaction, modifies that record, and then leaves the transaction open until you press ENTER. I want to be able to start the program and tell it to update ID 1; let it get its transaction and modify the record; start a second copy of the program and tell it to update ID 2; have it able to update (and commit) while the first app's transaction is still open. Currently it freezes at step 4, until I go back to the first copy of the app and close it or press ENTER so it commits. The call to command.ExecuteNonQuery blocks until the first connection is closed. public static void Main() { Console.Write("ID to update: "); var id = int.Parse(Console.ReadLine()); Console.WriteLine("Starting transaction"); using (var scope = new TransactionScope()) using (var connection = new SqlConnection(@"Data Source=localhost\sqlexpress;Initial Catalog=test1;Integrated Security=True")) { connection.Open(); var command = connection.CreateCommand(); command.CommandText = "UPDATE [Values] SET Value = 'Value' WHERE ID = " + id; Console.WriteLine("Updating record"); command.ExecuteNonQuery(); Console.Write("Press ENTER to end transaction: "); Console.ReadLine(); scope.Complete(); } } Here are some things I've already tried, with no change in behavior: Changing the transaction isolation level to "read uncommitted" Specifying a "WITH (ROWLOCK)" on the UPDATE statement

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  • QuickBox2D poly behaviour vs box or circle

    - by Ben Kanizay
    Hi I've played a little with Box2D before and have just started using QuickBox2D which makes things heaps easier. I am however getting different behaviour with a specific poly shape than I am with a box. All other properties are the same. I've included 3 simple examples and their source below. What I really want to work is Example 1 with both objects as poly. As you can see, it seems like the 'paddle' poly is the one that's failing - the 'ball' (whether it's a poly or circle) just falls straight through it instead of bouncing off as it does with a box 'paddle' object. Would appreciate some help or insight. As I can only post one line at this stage, the swf previews of the 3 examples can be seen here Example 1 source: package { import com.actionsnippet.qbox.QuickBox2D; import com.actionsnippet.qbox.QuickObject; import flash.display.MovieClip; public class Eg1 extends MovieClip { private var sim:QuickBox2D; private var paddle:QuickObject; private var ball:QuickObject; public function Eg1() { this.sim = new QuickBox2D(this); this.paddle = this.sim.addPoly({ x:13, y:19, angle:0, density:0, draggable:false, isBullet:true, verts:[[-3.84,-0.67,-2.84,-1,-2.17,-0.33,2.17,-0.33,2.84,-1,3.84,-0.67,2.84,1,-2.51,1]] }); this.ball = this.sim.addPoly({ x:13, y:1, restitution:1, friction:1, draggable:false, isBullet:true, verts:[[-0.34,-1,0.34,-1,0.67,-0.33,0.67,0.33,0.34,1,-0.34,1,-0.67,0.33,-0.67,-0.33]] }); this.sim.start(); } }} Example 2 source: package { import com.actionsnippet.qbox.QuickBox2D; import com.actionsnippet.qbox.QuickObject; import flash.display.MovieClip; public class Eg2 extends MovieClip { private var sim:QuickBox2D; private var paddle:QuickObject; private var ball:QuickObject; public function Eg2() { this.sim = new QuickBox2D(this); this.paddle = this.sim.addBox({ x:13, y:19, angle:0, density:0, draggable:false, isBullet:true, width:8 }); this.ball = this.sim.addPoly({ x:13, y:1, restitution:1, friction:1, draggable:false, isBullet:true, verts:[[-0.34,-1,0.34,-1,0.67,-0.33,0.67,0.33,0.34,1,-0.34,1,-0.67,0.33,-0.67,-0.33]] }); this.sim.start(); } }} Example 3 source: package { import com.actionsnippet.qbox.QuickBox2D; import com.actionsnippet.qbox.QuickObject; import flash.display.MovieClip; public class Eg3 extends MovieClip { private var sim:QuickBox2D; private var paddle:QuickObject; private var ball:QuickObject; public function Eg3() { this.sim = new QuickBox2D(this); this.paddle = this.sim.addPoly({ x:13, y:19, angle:0, density:0, draggable:false, isBullet:true, verts:[[-3.84,-0.67,-2.84,-1,-2.17,-0.33,2.17,-0.33,2.84,-1,3.84,-0.67,2.84,1,-2.51,1]] }); this.ball = this.sim.addCircle({ x:13, y:1, restitution:1, friction:1, draggable:false, isBullet:true, radius:1 }); this.sim.start(); } }}

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  • How to extract comment out of header file using python, perl, or sed?

    - by WilliamKF
    I have a header file like this: /* * APP 180-2 ALG-254/258/772 implementation * Last update: 03/01/2006 * Issue date: 08/22/2004 * * Copyright (C) 2006 Somebody's Name here * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the project nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef HEADER_H #define HEADER_H /* More comments and C++ code here. */ #endif /* End of file. */ And I wish to extract out the contents of the first C style comment only and drop the " *" at the start of each line to get a file with the following contents: APP 180-2 ALG-254/258/772 implementation Last update: 03/01/2006 Issue date: 08/22/2004 Copyright (C) 2006 Somebody's Name here All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. Neither the name of the project nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. Please suggest an easy way to do this with Python, Perl, sed, or some other way on Unix. Preferably as a one-liner.

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  • Listening for TCP and UDP requests on the same port

    - by user339328
    I am writing a Client/Server set of programs Depending on the operation requested by the client, I use make TCP or UDP request. Implementing the client side is straight-forward, since I can easily open connection with any protocol and send the request to the server-side. On the servers-side, on the other hand, I would like to listen both for UDP and TCP connections on the same port. Moreover, I like the the server to open new thread for each connection request. I have adopted the approach explained in: link text I have extended this code sample by creating new threads for each TCP/UDP request. This works correctly if I use TCP only, but it fails when I attempt to make UDP bindings. Please give me any suggestion how can I correct this. tnx Here is the Server Code: public class Server { public static void main(String args[]) { try { int port = 4444; if (args.length > 0) port = Integer.parseInt(args[0]); SocketAddress localport = new InetSocketAddress(port); // Create and bind a tcp channel to listen for connections on. ServerSocketChannel tcpserver = ServerSocketChannel.open(); tcpserver.socket().bind(localport); // Also create and bind a DatagramChannel to listen on. DatagramChannel udpserver = DatagramChannel.open(); udpserver.socket().bind(localport); // Specify non-blocking mode for both channels, since our // Selector object will be doing the blocking for us. tcpserver.configureBlocking(false); udpserver.configureBlocking(false); // The Selector object is what allows us to block while waiting // for activity on either of the two channels. Selector selector = Selector.open(); tcpserver.register(selector, SelectionKey.OP_ACCEPT); udpserver.register(selector, SelectionKey.OP_READ); System.out.println("Server Sterted on port: " + port + "!"); //Load Map Utils.LoadMap("mapa"); System.out.println("Server map ... LOADED!"); // Now loop forever, processing client connections while(true) { try { selector.select(); Set<SelectionKey> keys = selector.selectedKeys(); // Iterate through the Set of keys. for (Iterator<SelectionKey> i = keys.iterator(); i.hasNext();) { SelectionKey key = i.next(); i.remove(); Channel c = key.channel(); if (key.isAcceptable() && c == tcpserver) { new TCPThread(tcpserver.accept().socket()).start(); } else if (key.isReadable() && c == udpserver) { new UDPThread(udpserver.socket()).start(); } } } catch (Exception e) { e.printStackTrace(); } } } catch (Exception e) { e.printStackTrace(); System.err.println(e); System.exit(1); } } } The UDPThread code: public class UDPThread extends Thread { private DatagramSocket socket = null; public UDPThread(DatagramSocket socket) { super("UDPThread"); this.socket = socket; } @Override public void run() { byte[] buffer = new byte[2048]; try { DatagramPacket packet = new DatagramPacket(buffer, buffer.length); socket.receive(packet); String inputLine = new String(buffer); String outputLine = Utils.processCommand(inputLine.trim()); DatagramPacket reply = new DatagramPacket(outputLine.getBytes(), outputLine.getBytes().length, packet.getAddress(), packet.getPort()); socket.send(reply); } catch (IOException e) { e.printStackTrace(); } socket.close(); } } I receive: Exception in thread "UDPThread" java.nio.channels.IllegalBlockingModeException at sun.nio.ch.DatagramSocketAdaptor.receive(Unknown Source) at server.UDPThread.run(UDPThread.java:25) 10x

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  • Fastest way to read data from a lot of ASCII files

    - by Alsenes
    Hi guys, for a college exercise that I've already submitted I needed to read a .txt file wich contained a lot of names of images(1 in each line). Then I needed to open each image as an ascii file, and read their data(images where in ppm format), and do a series of things with them. The things is, I noticed my program was taking 70% of the time in the reading the data from the file part, instead of in the other calculations that I was doing (finding number of repetitions of each pixel with a hash table, finding diferents pixels beetween 2 images etc..), which I found quite odd to say the least. This is how the ppm format looks like: P3 //This value can be ignored when reading the file, because all image will be correctly formatted 4 4 255 //This value can be also ignored, will be always 255. 0 0 0 0 0 0 0 0 0 15 0 15 0 0 0 0 15 7 0 0 0 0 0 0 0 0 0 0 0 0 0 15 7 0 0 0 15 0 15 0 0 0 0 0 0 0 0 0 This is how I was reading the data from the files: ifstream fdatos; fdatos.open(argv[1]); //Open file with the name of all the images const int size = 128; char file[size]; //Where I'll get the image name Image *img; while (fdatos >> file) { //While there's still images anmes left, continue ifstream fimagen; fimagen.open(file); //Open image file img = new Image(fimagen); //Create new image object with it's data file ……… //Rest of the calculations whith that image ……… delete img; //Delete image object after done fimagen.close(); //Close image file after done } fdatos.close(); And inside the image object read the data like this: const int tallafirma = 100; char firma[tallafirma]; fich_in >> std::setw(100) >> firma; // Read the P3 part, can be ignored int maxvalue, numpixels; fich_in >> height >> width >> maxvalue; // Read the next three values numpixels = height*width; datos = new Pixel[numpixels]; int r,g,b; //Don't need to be ints, max value is 256, so an unsigned char would be ok. for (int i=0; i<numpixels; i++) { fich_in >> r >> g >> b; datos[i] = Pixel( r, g ,b); } //This last part is the slow one, //I thing I should be able to read all this data in one single read //to buffer or something which would be stored in an array of unsigned chars, //and then I'd only need to to do: //buffer[0] -> //Pixel 1 - Red data //buffer[1] -> //Pixel 1 - Green data //buffer[2] -> //Pixel 1 - Blue data So, any Ideas? I think I can improve it quite a bit reading all to an array in one single call, I just don't know how that is done. Also, is it posible to know how many images will be in the "index file"? Is it posiible to know the number of lines a file has?(because there's one file name per line..) Thanks!!

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  • Windows App. Thread Aborting Issue

    - by Patrick
    I'm working on an application that has to make specific decisions based on files that are placed into a folder being watched by a file watcher. Part of this decision making process involves renaming files before moving them off to another folder to be processed. Since I'm working with files of all different sizes I created an object that checks the file in a seperate thread to verify that it is "available" and when it is it fires an event. When I run the rename code from inside this available event it works. public void RenameFile_Test() { string psFilePath = @"C:\File1.xlsx"; tgt_File target = new FileObject(psFilePath); target.FileAvailable += new FileEventHandler(OnFileAvailable); target.FileUnAvailable += new FileEventHandler(OnFileUnavailable); } private void OnFileAvailable(object source, FileEventArgs e) { ((FileObject)source).RenameFile(@"C:\File2.xlsx"); } The problem I'm running into is that when the extensions are different from the source file and the rename to file I am making a call to a conversion factory that returns a factory object based on the type of conversion and then converts the file accordingly before doing the rename. When I run that particular piece of code in unit test it works, the factory object is returned, and the conversion happens correctly. But when I run it within the process I get up to the... moExcelApp = new Application(); part of converting an .xls or .xlsx to a .csv and i get a "Thread was being Aborted" error. Any thoughts? Update: There is a bit more information and a bit of map of how the application works currently. Client Application running FSW On File Created event Creates a FileObject passing in the path of the file. On construction the file is validated: if file exists is true then, Thread toAvailableCheck = new Thread(new ThreadStart(AvailableCheck)); toAvailableCheck.Start(); The AvailableCheck Method repeatedly tries to open a streamreader to the file until the reader is either created or the number of attempts times out. If the reader is opened, it fires the FileAvailable event, if not it fires the FileUnAvailable event, passing back itself in the event. The client application is wired to catch those events from inside the Oncreated event of the FSW. the OnFileAvailable method then calls the rename functionality which contains the excel interop call. If the file is being renamed (not converted, extensions stay the same) it does a move to change the name from the old file name to the new, and if its a conversion it runs a conversion factory object which returns the correct type of conversion based on the extensions of the source file and the destination file name. If it is a simple rename it works w/o a problem. If its a conversion (which is the XLS to CSV object that is returned as a part of the factory) the very first thing it does is create a new application object. That is where the application bombs. When i test the factory and conversion/rename process outside of the thread and in its own unit test the process works w/o a problem. Update: I tested the Excel Interop inside a thread by doing this: [TestMethod()] public void ExcelInteropTest() { Thread toExcelInteropThreadTest = new Thread(new ThreadStart(Instantiate_App)); toExcelInteropThreadTest.Start(); } private void Instantiate_App() { Application moExcelApp = new Application(); moExcelApp.Quit(); } And on the line where the application is instatntiated I got the 'A first chance exception of type 'System.Threading.ThreadAbortException' error. So I added; toExcelInteropThreadTest.SetApartmentState(ApartmentState.MTA); after the thread instantiation and before the thread start call and still got the same error. I'm getting the notion that I'm going to have to reconsider the design.

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  • Opening a file with a variable as name and checking for undefined values

    - by Harm De Weirdt
    I'm having some problems writing data into a file using Perl. sub startNewOrder{ my $name = makeUniqueFileName(); open (ORDER, ">$name.txt") or die "can't open file: $!\n"; format ORDER_TOP = PRODUCT<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<CODE<<<<<<<<AANTAL<<<<EENHEIDSPRIJS<<<<<<TOTAAL<<<<<<< . format ORDER = @<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< @<<<<<<<< @<<<< @<<<<<< @<<<<< $title, $code, $amount, $price, $total . close (ORDER); } This is the sub I use to make the file. (I translated most of it.) The makeUniqueFileName method makes a fileName based upon current time("minuteshoursdayOrder"). The problem now is that I have to write to this file in another sub. sub addToOrder{ print "give productcode:"; $code = <STDIN>; chop $code; print "Give amount:"; $amount = <STDIN>; chop $amount; if($inventory{$code} eq undef){ #Does the product exist? print "This product does not exist"; }elsif($inventory{$code}[2] < $amount && !defined($inventaris{$code}[2]) ){ #Is there enough in the inventory? print "There is not enough in stock" }else{ $inventory{$code}[2] -= $amount; #write in order file open (ORDER ">>$naam.txt") or die "can't open file: $!\n"; $title = $inventory{$code}[0]; $code = $code; $amount = $inventory{$code}[2]; $price = $inventory{$code}[1]; $total = $inventory{$code}[1]; write; close(ORDER); } %inventory is a hashtable that has the productcode as key and an array with the title, price and amount as value. There are two problems here: when I enter an invalid product number, I still have to enter an amount even while my code says it should print the error directly after checking if there is a product with the given code. The second problem is that the writing doesn't seem to work. It always give's a "No such file or directory" error. Is there a way to open the ORDER file I made in the first sub without having to make $name not local? Or just a way to write in this file? I really don't know how to start here. I can't really find much info on writing a file that has been closed before, and in a different sub. Any help is appreciated, Harm

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  • Override `drop` for a custom sequence

    - by Bruno Reis
    In short: in Clojure, is there a way to redefine a function from the standard sequence API (which is not defined on any interface like ISeq, IndexedSeq, etc) on a custom sequence type I wrote? 1. Huge data files I have big files in the following format: A long (8 bytes) containing the number n of entries n entries, each one being composed of 3 longs (ie, 24 bytes) 2. Custom sequence I want to have a sequence on these entries. Since I cannot usually hold all the data in memory at once, and I want fast sequential access on it, I wrote a class similar to the following: (deftype DataSeq [id ^long cnt ^long i cached-seq] clojure.lang.IndexedSeq (index [_] i) (count [_] (- cnt i)) (seq [this] this) (first [_] (first cached-seq)) (more [this] (if-let [s (next this)] s '())) (next [_] (if (not= (inc i) cnt) (if (next cached-seq) (DataSeq. id cnt (inc i) (next cached-seq)) (DataSeq. id cnt (inc i) (with-open [f (open-data-file id)] ; open a memory mapped byte array on the file ; seek to the exact position to begin reading ; decide on an optimal amount of data to read ; eagerly read and return that amount of data )))))) The main idea is to read ahead a bunch of entries in a list and then consume from that list. Whenever the cache is completely consumed, if there are remaining entries, they are read from the file in a new cache list. Simple as that. To create an instance of such a sequence, I use a very simple function like: (defn ^DataSeq load-data [id] (next (DataSeq. id (count-entries id) -1 []))) ; count-entries is a trivial "open file and read a long" memoized As you can see, the format of the data allowed me to implement count in very simply and efficiently. 3. drop could be O(1) In the same spirit, I'd like to reimplement drop. The format of these data files allows me to reimplement drop in O(1) (instead of the standard O(n)), as follows: if dropping less then the remaining cached items, just drop the same amount from the cache and done; if dropping more than cnt, then just return the empty list. otherwise, just figure out the position in the data file, jump right into that position, and read data from there. My difficulty is that drop is not implemented in the same way as count, first, seq, etc. The latter functions call a similarly named static method in RT which, in turn, calls my implementation above, while the former, drop, does not check if the instance of the sequence it is being called on provides a custom implementation. Obviously, I could provide a function named anything but drop that does exactly what I want, but that would force other people (including my future self) to remember to use it instead of drop every single time, which sucks. So, the question is: is it possible to override the default behaviour of drop? 4. A workaround (I dislike) While writing this question, I've just figured out a possible workaround: make the reading even lazier. The custom sequence would just keep an index and postpone the reading operation, that would happen only when first was called. The problem is that I'd need some mutable state: the first call to first would cause some data to be read into a cache, all the subsequent calls would return data from this cache. There would be a similar logic on next: if there's a cache, just next it; otherwise, don't bother populating it -- it will be done when first is called again. This would avoid unnecessary disk reads. However, this is still less than optimal -- it is still O(n), and it could easily be O(1). Anyways, I don't like this workaround, and my question is still open. Any thoughts? Thanks.

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  • Opening a file with a variable as name & checking for undefined values

    - by Harm De Weirdt
    Hello everyone. I'm having some problems writing data into a file using perl. sub startNewOrder{ my $name = makeUniqueFileName(); open (ORDER, ">$name.txt") or die "can't open file: $!\n"; format ORDER_TOP = PRODUCT<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<CODE<<<<<<<<AANTAL<<<<EENHEIDSPRIJS<<<<<<TOTAAL<<<<<<< . format ORDER = @<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< @<<<<<<<< @<<<< @<<<<<< @<<<<< $title, $code, $amount, $price, $total . close (ORDER); } This is the sub I use to make the file. (I translated most of it) The makeUniqueFileName method makes a fileName based upon current time("minuteshoursdayOrder"). The problem now is that I have to write in this file in another sub. sub addToOrder{ print "give productcode:"; $code = <STDIN>; chop $code; print "Give amount:"; $amount = <STDIN>; chop $amount; if($inventory{$code} eq undef){ #Does the product exist? print "This product does not exist"; }elsif($inventory{$code}[2] < $amount && !defined($inventaris{$code}[2]) ){ #Is there enough in the inventory? print "There is not enough in stock" }else{ $inventory{$code}[2] -= $amount; #write in order file open (ORDER ">>$naam.txt") or die "can't open file: $!\n"; $title = $inventory{$code}[0]; $code = $code; $amount = $inventory{$code}[2]; $price = $inventory{$code}[1]; $total = $inventory{$code}[1]; write; close(ORDER); } %inventory is a hashtable that has the productcode as key and an array with the title, price and amount as value. There are two problems here: when I enter an invalid product number, I still have to enter an amount even while my code says it should print the error directly after checking if there is a product with the given code. The second problem is that the writing doesn't seem to work. It always give's a "No such file or directory" error. Is there a way to open the ORDER file i made in the first sub without having to make $name not local? Or just a way to write in this file? I really don't know how to start here. I can't really find much info on writing a file that has been closed before, and in a different sub.. Any help is appreciated, Harm

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  • Setting a Visual State from a data bound enum in WPF

    - by firoso
    Hey all, I've got a scenario where I want to switch the visiblity of 4 different content controls. The visual states I have set opacity, and collapsed based on each given state (See code.) What I'd like to do is have the visual state bound to a property of my View Model of type Enum. I tried using DataStateBehavior, but it requires true/false, which doesn't work for me. So I tried DataStateSwitchBehavior, which seems to be totally broken for WPF4 from what I could tell. Is there a better way to be doing this? I'm really open to different approaches if need be, but I'd really like to keep this enum in the equation. Edit: The code shouldn't be too important, I just need to know if there's a well known solution to this problem. <UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:Custom="http://schemas.microsoft.com/expression/2010/interactivity" xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions" xmlns:ee="http://schemas.microsoft.com/expression/2010/effects" xmlns:customBehaviors="clr-namespace:SEL.MfgTestDev.ESS.Behaviors" x:Class="SEL.MfgTestDev.ESS.View.PresenterControl" mc:Ignorable="d" d:DesignHeight="624" d:DesignWidth="1104" d:DataContext="{Binding ApplicationViewModel, Mode=OneWay, Source={StaticResource Locator}}"> <Grid> <Grid.Resources> <ResourceDictionary> <ResourceDictionary.MergedDictionaries> <ResourceDictionary Source="Layout/TerminalViewTemplate.xaml"/> <ResourceDictionary Source="Layout/DebugViewTemplate.xaml"/> <ResourceDictionary Source="Layout/ProgressViewTemplate.xaml"/> <ResourceDictionary Source="Layout/LoadoutViewTemplate.xaml"/> </ResourceDictionary.MergedDictionaries> </ResourceDictionary> </Grid.Resources> <Custom:Interaction.Behaviors> <customBehaviors:DataStateSwitchBehavior Binding="{Binding ApplicationViewState}"> <customBehaviors:DataStateSwitchCase State="LoadoutState" Value="Loadout"/> </customBehaviors:DataStateSwitchBehavior> </Custom:Interaction.Behaviors> <VisualStateManager.VisualStateGroups> <VisualStateGroup x:Name="ApplicationStates" ei:ExtendedVisualStateManager.UseFluidLayout="True"> <VisualStateGroup.Transitions> <VisualTransition GeneratedDuration="0:0:1"> <VisualTransition.GeneratedEasingFunction> <SineEase EasingMode="EaseInOut"/> </VisualTransition.GeneratedEasingFunction> <ei:ExtendedVisualStateManager.TransitionEffect> <ee:SmoothSwirlGridTransitionEffect/> </ei:ExtendedVisualStateManager.TransitionEffect> </VisualTransition> </VisualStateGroup.Transitions> <VisualState x:Name="LoadoutState"> <Storyboard> <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="LoadoutPage"> <EasingDoubleKeyFrame KeyTime="0" Value="1"/> </DoubleAnimationUsingKeyFrames> <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="LoadoutPage"> <DiscreteObjectKeyFrame KeyTime="0" Value="{x:Static Visibility.Visible}"/> </ObjectAnimationUsingKeyFrames> </Storyboard> </VisualState> <VisualState x:Name="ProgressState"> <Storyboard> <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="ProgressPage"> <EasingDoubleKeyFrame KeyTime="0" Value="1"/> </DoubleAnimationUsingKeyFrames> <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="ProgressPage"> <DiscreteObjectKeyFrame KeyTime="0" Value="{x:Static Visibility.Visible}"/> </ObjectAnimationUsingKeyFrames> </Storyboard> </VisualState> <VisualState x:Name="DebugState"> <Storyboard> <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="DebugPage"> <DiscreteObjectKeyFrame KeyTime="0" Value="{x:Static Visibility.Visible}"/> </ObjectAnimationUsingKeyFrames> <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="DebugPage"> <EasingDoubleKeyFrame KeyTime="0" Value="1"/> </DoubleAnimationUsingKeyFrames> </Storyboard> </VisualState> <VisualState x:Name="TerminalState"> <Storyboard> <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="TerminalPage"> <DiscreteObjectKeyFrame KeyTime="0" Value="{x:Static Visibility.Visible}"/> </ObjectAnimationUsingKeyFrames> <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="TerminalPage"> <EasingDoubleKeyFrame KeyTime="0" Value="1"/> </DoubleAnimationUsingKeyFrames> </Storyboard> </VisualState> </VisualStateGroup> </VisualStateManager.VisualStateGroups> <ContentControl x:Name="LoadoutPage" ContentTemplate="{StaticResource LoadoutViewTemplate}" Opacity="0" Content="{Binding}" Visibility="Collapsed"/> <ContentControl x:Name="ProgressPage" ContentTemplate="{StaticResource ProgressViewTemplate}" Opacity="0" Content="{Binding}" Visibility="Collapsed"/> <ContentControl x:Name="DebugPage" ContentTemplate="{StaticResource DebugViewTemplate}" Opacity="0" Content="{Binding}" Visibility="Collapsed"/> <ContentControl x:Name="TerminalPage" ContentTemplate="{StaticResource TerminalViewTemplate}" Opacity="0" Content="{Binding}" Visibility="Collapsed"/> <TextBlock HorizontalAlignment="Left" TextWrapping="Wrap" VerticalAlignment="Top" Text="{Binding ApplicationViewState}"> <TextBlock.Background> <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0"> <GradientStop Color="Black" Offset="0"/> <GradientStop Color="White" Offset="1"/> </LinearGradientBrush> </TextBlock.Background> </TextBlock> </Grid>

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  • Recommendations on developing a WPF application without using MVVM or similar

    - by Metro Smurf
    We were building out the next version of an in-house thick-client application using WPF/Prism (Composite Application Library). As we were nearly done with the client our team was put under new management and shortly thereafter: We were then directed to drop the Prism framework to keep things simple. This includes not using any type of Inversion of Control. We were directed to build out the WPF application without using MVVM or similar; and more along the lines of a traditional WinForm application. The idea is that if a developer sees a control in Visual Studio’s designer view, then (s)he should be able to click on the control and see exactly what it's doing without having to traverse through a view-model (or similar). We have now been tasked with building out the WPF application using one primary Window, use a Frame Control to contain the content, and use a Ribbon outside of the frame for the menu items. Reason we were provided to use Frame Control: a. We will show a view in the Frame with a Page (not a user control) and then load the page in the Frame. b. When a new view is to be shown in the Frame, the current view (Page) will be closed/disposed and the new view (Page) will take its place in the Frame. c. When a developer looks at the Page in design view, (s)he will be able to click on any control and see exactly what is being done. Given the restrictions of 1 and 2 above, we’d like to present another method of building out the application that: Can be presented as an alternative to using the “Frame Methodology” (item 3 above) but still provides the same type of functionality. Does not use MVVM (see #1 and #2 above). Provided the direction we’ve been given, any suggestions as to an alternative we can present? I’d request that the responses be kept on the professional level and thank you in advance.

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  • validation in datagrid while insert update in asp.net

    - by abhi
    <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default7.aspx.cs" Inherits="Default7" % <%@ Register Assembly="Telerik.Web.UI" Namespace="Telerik.Web.UI" TagPrefix="telerik" % Untitled Page   <telerik:GridTemplateColumn Visible="false"> <ItemTemplate> <asp:Label ID="lblEmpID" runat="server" Text='<%# bind("pid") %>'> </asp:Label> </ItemTemplate> </telerik:GridTemplateColumn> <telerik:GridBoundColumn UniqueName="Fname" HeaderText="Fname" DataField="Fname" CurrentFilterFunction="NotIsNull" SortExpression="Fname"> </telerik:GridBoundColumn> <telerik:GridBoundColumn UniqueName="Lname" HeaderText="Lname" DataField="Lname" CurrentFilterFunction="NotIsNull" SortExpression="Lname"> </telerik:GridBoundColumn> <telerik:GridBoundColumn UniqueName="Designation" HeaderText="Designation" DataField="Designation" CurrentFilterFunction="NotIsNull" SortExpression="Designation"> </telerik:GridBoundColumn> <telerik:GridEditCommandColumn> </telerik:GridEditCommandColumn> <telerik:GridButtonColumn CommandName="Delete" Text="Delete" UniqueName="column"> </telerik:GridButtonColumn> </Columns> <EditFormSettings> <FormTemplate> <table> <tr> <td>Fname*</td> <td> <asp:HiddenField ID="Fname" runat="server" Visible="false" /> <asp:TextBox ID="txtFname" runat="server" Text='<%#("Fname")%>'> </asp:TextBox> <asp:RequiredFieldValidator ID="EvalFname" ControlToValidate="txtFname" ErrorMessage="Enter Name" runat="server" ValidationGroup="Update"> *</asp:RequiredFieldValidator> </td> </tr> <tr> <td>Lname*</td> <td> <asp:HiddenField ID="HiddenField1" runat="server" Visible="false" /> <asp:TextBox ID="txtLname" runat="server" Text='<%#("Lname")%>'> </asp:TextBox> <asp:RequiredFieldValidator ID="RequiredFieldValidator1" ControlToValidate="txtLname" ErrorMessage="Enter Name" runat="server" ValidationGroup="Update"> *</asp:RequiredFieldValidator> </td> </tr> <tr> <td>Designation* </td> <td> <asp:HiddenField ID="HiddenField2" runat="server" Visible="false" /> <asp:TextBox ID="txtDesignation" runat="server" Text='<%#("Designation")%>'> </asp:TextBox> <asp:RequiredFieldValidator ID="RequiredFieldValidator2" ControlToValidate="txtDesignation" ErrorMessage="Enter Designation" runat="server" ValidationGroup="Update"> *</asp:RequiredFieldValidator> </td> </tr> </table> </FormTemplate> <EditColumn UpdateText="Update record" UniqueName="EditCommandColumn1" CancelText="Cancel edit"> </EditColumn> </EditFormSettings> </MasterTableView> </telerik:RadGrid> </form> this is my code i want to perform validation using the required validators but i think m missing smthin so pls help, here's my code behind using System; using System.Data; using System.Configuration; using System.Collections; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; using System.Data.SqlClient; using Telerik.Web.UI; public partial class Default7 : System.Web.UI.Page { string strQry; public SqlDataAdapter da; public DataSet ds; public SqlCommand cmd; public DataTable dt; string strCon = "Data Source=MINETDEVDATA; Initial Catalog=ML_SuppliersProd; User Id=sa; Password=@MinetApps7;"; public SqlConnection con; protected void Page_Load(object sender, EventArgs e) { } protected void RadGrid1_NeedDataSource(object source, Telerik.Web.UI.GridNeedDataSourceEventArgs e) { dt = new DataTable(); con = new SqlConnection(strCon); da = new SqlDataAdapter(); try { strQry = "SELECT * FROM table2"; con.Open(); da.SelectCommand = new SqlCommand(strQry,con); da.Fill(dt); RadGrid1.DataSource = dt; } finally { con.Close(); } } protected void RadGrid1_DeleteCommand(object source, Telerik.Web.UI.GridCommandEventArgs e) { con = new SqlConnection(strCon); cmd = new SqlCommand(); GridDataItem item = (GridDataItem)e.Item; string pid = item.OwnerTableView.DataKeyValues[item.ItemIndex]["pid"].ToString(); con.Open(); string delete = "DELETE from table2 where pid='"+pid+"'"; cmd.CommandText = delete; cmd.Connection = con; cmd.ExecuteNonQuery(); con.Close(); } protected void RadGrid1_UpdateCommand(object source, GridCommandEventArgs e) { GridEditableItem radgriditem = e.Item as GridEditableItem; string pid = radgriditem.OwnerTableView.DataKeyValues[radgriditem.ItemIndex]["pid"].ToString(); string firstname = (radgriditem["Fname"].Controls[0] as TextBox).Text; string lastname = (radgriditem["Lname"].Controls[0] as TextBox).Text; string designation = (radgriditem["Designation"].Controls[0] as TextBox).Text; con = new SqlConnection(strCon); cmd = new SqlCommand(); try { con.Open(); string update = "UPDATE table2 set Fname='" + firstname + "',Lname='" + lastname + "',Designation='" + designation + "' WHERE pid='" + pid + "'"; cmd.CommandText = update; cmd.Connection = con; cmd.ExecuteNonQuery(); con.Close(); } catch (Exception ex) { RadGrid1.Controls.Add(new LiteralControl("Unable to update Reason: " + ex.Message)); e.Canceled = true; } } protected void RadGrid1_InsertCommand(object source, GridCommandEventArgs e) { GridEditFormInsertItem insertitem = (GridEditFormInsertItem)e.Item; string firstname = (insertitem["Fname"].Controls[0] as TextBox).Text; string lastname = (insertitem["Lname"].Controls[0] as TextBox).Text; string designation = (insertitem["Designation"].Controls[0] as TextBox).Text; con = new SqlConnection(strCon); cmd = new SqlCommand(); try { con.Open(); String insertQuery = "INSERT into table1(Fname,Lname,Designation) Values ('" + firstname + "','" + lastname + "','" + designation + "')"; cmd.CommandText = insertQuery; cmd.Connection = con; cmd.ExecuteNonQuery(); con.Close(); } catch(Exception ex) { RadGrid1.Controls.Add(new LiteralControl("Unable to insert Reason:" + ex.Message)); e.Canceled = true; } } }

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  • gunit syntax for tree walker with a flat list of nodes

    - by Kaleb Pederson
    Here's a simple gunit test for a portion of my tree grammar which generates a flat list of nodes: objectOption walks objectOption: <<one:"value">> -> (one "value") Although you define a tree in ANTLR's rewrite syntax using a caret (i.e. ^(ROOT child...)), gunit matches trees without the caret, so the above represents a tree and it's not surprising that it fails: it's a flat list of nodes and not a tree. This results in a test failure: 1 failures found: test2 (objectOption walks objectOption, line17) - expected: (one \"value\") actual: one \"value\" Another option which seems intuitive is to leave off the parenthesis, like this: objectOption walks objectOption: <<one:"value">> -> one "value" But gunit doesn't like this syntax. It seems to result in a parse failure in the gunit grammar: line 17:20 no viable alternative at input 'one' line 17:24 missing ':' at 'value' line 0:-1 no viable alternative at input '<EOF>' java.lang.NullPointerException at org.antlr.gunit.OutputTest.getExpected(OutputTest.java:65) at org.antlr.gunit.gUnitExecutor.executeTests(gUnitExecutor.java:245) ... What is the correct way to match a flat tree?

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  • SCM for Xcode?

    - by Gregor
    I am developing an application for the Mac as a small team (me + another person) effort. We are located in different cities, and have started to see the need for solid source control management. None of us have any experience with this, and both of us are relatively new to Cocoa/Obj-C/Xcode (but do have C knowledge). Does anyone have any recommendations as to which SCM system to choose? I understand that a lot of people are using Subversion, which is also supported in Xcode 3.1. Does anyone have experience with using Subversion through Xcode? Or is it a better option to chose a stand alone GUI alternative, such as Versions? Grateful for any input on this. Gregor Tomasevic, Sweden Update/personal experiences: Since this post, we have tried Versions and Cornerstone (both of which are SVN GUI-clients), as well as Xcodes built-in support for SVN. We were not particularly pleased with Versions, which seemed to have some problems with committing unversioned files/build files. The built-in SVN support in Xcode works quite well, although it probably has limitations that we have still not run into. Cornerstone is both simple to use and powerful, and does not seem to suffer from the problems we encountered with Versions. So far, we have just tried committing, updating repo, checking out latest/previous versions of our files and worked some with file comparison. It might be a whole different ball game once you start working extensively with branching, an area which we have been told both these GUI clients might have some weaknesses in. For what it's worth (and with only days of evaluation) Cornerstone seems to be a somewhat better alternative, although for simpler SCM, Xcode works well too. Thanks for all the comments.

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  • Could not synchronize database state with session

    - by user359427
    Hello all, I'm having trouble trying to persist an entity which ID is a generated value. This entity (A), at persistence time, has to persist in cascade another entity(B). The relationship within A and B is OneToMany, and the property related in B is part of a composite key. I'm using Eclipse, JBOSS Runtime, JPA/Hibernate Here is my code: Entity A: @Entity public class Cambios implements Serializable { private static final long serialVersionUID = 1L; @SequenceGenerator(name="CAMBIOS_GEN",sequenceName="CAMBIOS_SEQ",allocationSize=1) @Id @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="CAMBIOS_GEN") @Column(name="ID_CAMBIO") private Long idCambio; //bi-directional many-to-one association to ObjetosCambio @OneToMany(cascade={CascadeType.PERSIST},mappedBy="cambios") private List<ObjetosCambio> objetosCambioList; public Cambios() { } ... } Entity B: @Entity @Table(name="OBJETOS_CAMBIO") public class ObjetosCambio implements Serializable { private static final long serialVersionUID = 1L; @EmbeddedId private ObjetosCambioPK id; //bi-directional many-to-one association to Cambios @ManyToOne @JoinColumn(name="ID_CAMBIO", insertable=false, updatable=false) private Cambios cambios; //bi-directional many-to-one association to Objetos @ManyToOne @JoinColumn(name="ID_OBJETO", insertable=false, updatable=false) private Objetos objetos; public ObjetosCambio() { } ... Entity B PK: @Embeddable public class ObjetosCambioPK implements Serializable { //default serial version id, required for serializable classes. private static final long serialVersionUID = 1L; @Column(name="ID_OBJETO") private Long idObjeto; @Column(name="ID_CAMBIO") private Long idCambio; public ObjetosCambioPK() { } Client: public String generarCambio(){ ServiceLocator serviceLocator = null; try { serviceLocator = serviceLocator.getInstance(); FachadaLocal tcLocal; tcLocal = (FachadaLocal)serviceLocator.getFacadeService("java:comp/env/negocio/Fachada"); Cambios cambio = new Cambios(); Iterator it = objetosLocal.iterator(); //OBJETOSLOCAL IS ALREADY POPULATED OUTSIDE OF THIS METHOD List<ObjetosCambio> ocList = new ArrayList(); while (it.hasNext()){ Objetos objeto = (Objetos)it.next(); ObjetosCambio objetosCambio = new ObjetosCambio(); objetosCambio.setCambios(cambio); //AT THIS TIME THIS "CAMBIO" DOES NOT HAVE ITS ID, ITS SUPPOSED TO BE GENERATED AT PERSISTENCE TIME ObjetosCambioPK ocPK = new ObjetosCambioPK(); ocPK.setIdObjeto(objeto.getIdObjeto()); objetosCambio.setId(ocPK); ocList.add(objetosCambio); } cambio.setObjetosCambioList(ocList); tcLocal.persistEntity(cambio); return "exito"; } catch (NamingException e) { // TODO e.printStackTrace(); } return null; } ERROR: 15:23:25,717 WARN [JDBCExceptionReporter] SQL Error: 1400, SQLState: 23000 15:23:25,717 ERROR [JDBCExceptionReporter] ORA-01400: no se puede realizar una inserción NULL en ("CDC"."OBJETOS_CAMBIO"."ID_CAMBIO") 15:23:25,717 WARN [JDBCExceptionReporter] SQL Error: 1400, SQLState: 23000 15:23:25,717 ERROR [JDBCExceptionReporter] ORA-01400: no se puede realizar una inserción NULL en ("CDC"."OBJETOS_CAMBIO"."ID_CAMBIO") 15:23:25,717 ERROR [AbstractFlushingEventListener] Could not synchronize database state with session org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:94) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:275) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:266) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:167) at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321) at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50) at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1027) at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:365) at org.hibernate.ejb.AbstractEntityManagerImpl$1.beforeCompletion(AbstractEntityManagerImpl.java:504) at com.arjuna.ats.internal.jta.resources.arjunacore.SynchronizationImple.beforeCompletion(SynchronizationImple.java:101) at com.arjuna.ats.arjuna.coordinator.TwoPhaseCoordinator.beforeCompletion(TwoPhaseCoordinator.java:269) at com.arjuna.ats.arjuna.coordinator.TwoPhaseCoordinator.end(TwoPhaseCoordinator.java:89) at com.arjuna.ats.arjuna.AtomicAction.commit(AtomicAction.java:177) at com.arjuna.ats.internal.jta.transaction.arjunacore.TransactionImple.commitAndDisassociate(TransactionImple.java:1423) at com.arjuna.ats.internal.jta.transaction.arjunacore.BaseTransaction.commit(BaseTransaction.java:137) at com.arjuna.ats.jbossatx.BaseTransactionManagerDelegate.commit(BaseTransactionManagerDelegate.java:75) at org.jboss.aspects.tx.TxPolicy.endTransaction(TxPolicy.java:170) at org.jboss.aspects.tx.TxPolicy.invokeInOurTx(TxPolicy.java:87) at org.jboss.aspects.tx.TxInterceptor$Required.invoke(TxInterceptor.java:190) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) at org.jboss.aspects.tx.TxPropagationInterceptor.invoke(TxPropagationInterceptor.java:76) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) at org.jboss.ejb3.tx.NullInterceptor.invoke(NullInterceptor.java:42) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) at org.jboss.ejb3.security.Ejb3AuthenticationInterceptorv2.invoke(Ejb3AuthenticationInterceptorv2.java:186) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) at org.jboss.ejb3.ENCPropagationInterceptor.invoke(ENCPropagationInterceptor.java:41) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) at org.jboss.ejb3.BlockContainerShutdownInterceptor.invoke(BlockContainerShutdownInterceptor.java:67) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) at org.jboss.aspects.currentinvocation.CurrentInvocationInterceptor.invoke(CurrentInvocationInterceptor.java:67) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) at org.jboss.ejb3.session.SessionSpecContainer.invoke(SessionSpecContainer.java:176) at org.jboss.ejb3.session.SessionSpecContainer.invoke(SessionSpecContainer.java:216) at org.jboss.ejb3.proxy.impl.handler.session.SessionProxyInvocationHandlerBase.invoke(SessionProxyInvocationHandlerBase.java:207) at org.jboss.ejb3.proxy.impl.handler.session.SessionProxyInvocationHandlerBase.invoke(SessionProxyInvocationHandlerBase.java:164) at $Proxy298.persistEntity(Unknown Source) at backing.SolicitudCambio.generarCambio(SolicitudCambio.java:521) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at com.sun.faces.el.MethodBindingImpl.invoke(MethodBindingImpl.java:146) at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:92) at javax.faces.component.UICommand.broadcast(UICommand.java:332) at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:287) at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:401) at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:95) at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:245) at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:110) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:213) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:301) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:235) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:190) at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:92) at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126) at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:598) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447) at java.lang.Thread.run(Unknown Source) Caused by: java.sql.BatchUpdateException: ORA-01400: no se puede realizar una inserción NULL en ("CDC"."OBJETOS_CAMBIO"."ID_CAMBIO") Thanks in advance! JM.-

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  • ASP.NET MVC 1 and 2 on Mono 2.4 with Fluent NHibernate

    - by SztupY
    Hi! I'd like to create an application using ASP.NET MVC, that should run under mono 2.4 (compiling will be done on a Windows box). Has anyone getting luck with this? Here is what I've already tried: ASP.NET MVC on mono without any persistence model support, and using nhaml as the view engine S#aml architecture, which is a quite good framework imho, but it depends too much on stuff, that are not working good under mono (like windsor) The first part worked fine, I didn't encounter any major problems. But I couldn't get the second part working. It seems it's dependency on Castle.Windsor breaks the whole mono support (but there might be other parts too). Therefore I decided to create an alternative framework, that borrows some of the ideas of s#arp-architecture, but designed to be working under mono (and if I'm able to do this I'll release it for the community of course). The controller and view part is working fine (not much magic here though, they have been always working), but I have some questions before I start job on the persistence part: What NHibernate versions are working under mono? I've heard 1.2 is working fine. Does 2.0.1/2.1 beta work under mono? Does Fluent.NHibernate and NHibernate.Linq work under mono? (for the latter it seems it needs some dependcies that aren't avaialable in mono) Are there any good alternatives for persistence support to NHibernate under mono? Alternative questions: Are there any frameworks that have mono+persistence+asp.net mvc support already or am I the first one to think about this? If you have already done this: what are your opinions on stability/usability? Thanks for the answers EDIT: Updated the framework to support ASP.NET MVC 2: http://shaml.sztupy.hu/

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  • WCF: WTF! Does WCF raise the bar or just the complexity level?

    - by rp
    I understand the value of the three-part service/host/client model offered by WCF. But is it just me or does it seem like WCF took something pretty direct and straightforward (the ASMX model) and made a mess out of it? Is there an alternative to using SvcUtil's command line step back in time to generate the proxy? With ASMX services a test harness was automatically provided; is there a good alternative today with WCF? I appreciate that the WS* stuff is more tightly integrated with WCF and hope to find some payoff for WCF there, but geeze, otherwise I'm perplexed. Also, the state of books available for WCF is abysmal at best. Juval Lowy, a superb author, has written a good O'Reilly reference book "Programming WCF Services" but it doesn't do that much (for me anyway) for learning now to use WCF. That book's precursor (and a little better organized, but not much, as a tutorial) is Michele Leroux Bustamante's Learning WCF. It has good spots but is outdated in place and its corresponding Web site is gone. Do you have good WCF learning references besides just continuing to Google the bejebus out of things? Thanks, rp

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  • Char error C langauge

    - by Nadeem tabbaa
    i have a project for a course, i did almost everything but i have this error i dont know who to solve it... the project about doing our own shell some of them we have to write our code, others we will use the fork method.. this is the code, #include <sys/wait.h> #include <dirent.h> #include <limits.h> #include <errno.h> #include <stdlib.h> #include <string.h> #include<stdio.h> #include<fcntl.h> #include<unistd.h> #include<sys/stat.h> #include<sys/types.h> int main(int argc, char **argv) { pid_t pid; char str[21], *arg[10]; int x,status,number; system("clear"); while(1) { printf("Rshell>" ); fgets(str,21,stdin); x = 0; arg[x] = strtok(str, " \n\t"); while(arg[x]) arg[++x] = strtok(NULL, " \n\t"); if(NULL!=arg[0]) { if(strcasecmp(arg[0],"cat")==0) //done { int f=0,n; char l[1]; struct stat s; if(x!=2) { printf("Mismatch argument\n"); } /*if(access(arg[1],F_OK)) { printf("File Exist"); exit(1); } if(stat(arg[1],&s)<0) { printf("Stat ERROR"); exit(1); } if(S_ISREG(s.st_mode)<0) { printf("Not a Regular FILE"); exit(1); } if(geteuid()==s.st_uid) if(s.st_mode & S_IRUSR) f=1; else if(getegid()==s.st_gid) if(s.st_mode & S_IRGRP) f=1; else if(s.st_mode & S_IROTH) f=1; if(!f) { printf("Permission denied"); exit(1); }*/ f=open(arg[1],O_RDONLY); while((n=read(f,l,1))>0) write(1,l,n); } else if(strcasecmp(arg[0],"rm")==0) //done { if( unlink( arg[1] ) != 0 ) perror( "Error deleting file" ); else puts( "File successfully deleted" ); } else if(strcasecmp(arg[0],"rmdir")==0) //done { if( remove( arg[1] ) != 0 ) perror( "Error deleting Directory" ); else puts( "Directory successfully deleted" ); } else if(strcasecmp(arg[0],"ls")==0) //done { DIR *dir; struct dirent *dirent; char *where = NULL; //printf("x== %i\n",x); //printf("x== %s\n",arg[1]); //printf("x== %i\n",get_current_dir_name()); if (x == 1) where = get_current_dir_name(); else where = arg[1]; if (NULL == (dir = opendir(where))) { fprintf(stderr,"%d (%s) opendir %s failed\n", errno, strerror(errno), where); return 2; } while (NULL != (dirent = readdir(dir))) { printf("%s\n", dirent->d_name); } closedir(dir); } else if(strcasecmp(arg[0],"cp")==0) //not yet for Raed { FILE *from, *to; char ch; if(argc!=3) { printf("Usage: copy <source> <destination>\n"); exit(1); } /* open source file */ if((from = fopen(argv[1], "rb"))==NULL) { printf("Cannot open source file.\n"); exit(1); } /* open destination file */ if((to = fopen(argv[2], "wb"))==NULL) { printf("Cannot open destination file.\n"); exit(1); } /* copy the file */ while(!feof(from)) { ch = fgetc(from); if(ferror(from)) { printf("Error reading source file.\n"); exit(1); } if(!feof(from)) fputc(ch, to); if(ferror(to)) { printf("Error writing destination file.\n"); exit(1); } } if(fclose(from)==EOF) { printf("Error closing source file.\n"); exit(1); } if(fclose(to)==EOF) { printf("Error closing destination file.\n"); exit(1); } } else if(strcasecmp(arg[0],"mv")==0)//done { if( rename(arg[1],arg[2]) != 0 ) perror( "Error moving file" ); else puts( "File successfully moved" ); } else if(strcasecmp(arg[0],"hi")==0)//done { printf("hello\n"); } else if(strcasecmp(arg[0],"exit")==0) // done { return 0; } else if(strcasecmp(arg[0],"sleep")==0) // done { if(x==1) printf("plz enter the # seconds to sleep\n"); else sleep(atoi(arg[1])); } else if(strcmp(arg[0],"history")==0) // not done { FILE *infile; //char fname[40]; char line[100]; int lcount; ///* Read in the filename */ //printf("Enter the name of a ascii file: "); //fgets(History.txt, sizeof(fname), stdin); /* Open the file. If NULL is returned there was an error */ if((infile = fopen("History.txt", "r")) == NULL) { printf("Error Opening File.\n"); exit(1); } while( fgets(line, sizeof(line), infile) != NULL ) { /* Get each line from the infile */ lcount++; /* print the line number and data */ printf("Line %d: %s", lcount, line); } fclose(infile); /* Close the file */ writeHistory(arg); //write to txt file every new executed command //read from the file once the history command been called //if a command called not for the first time then just replace it to the end of the file } else if(strncmp(arg[0],"@",1)==0) // not done { //scripting files // read from the file command by command and executing them } else if(strcmp(arg[0],"type")==0) //not done { //if(x==1) //printf("plz enter the argument\n"); //else //type((arg[1])); } else { pid = fork( ); if (pid == 0) { execlp(arg[0], arg[0], arg[1], arg[2], NULL); printf ("EXEC Failed\n"); } else { wait(&status); if(strcmp(arg[0],"clear")!=0) { printf("status %04X\n",status); if(WIFEXITED(status)) printf("Normal termination, exit code %d\n", WEXITSTATUS(status)); else printf("Abnormal termination\n"); } } } } } } void writeHistory(char *arg[]) { FILE *file; file = fopen("History.txt","a+"); /* apend file (add text to a file or create a file if it does not exist.*/ int i =0; while(strcasecmp(arg[0],NULL)==0) { fprintf(file,"%s ",arg[i]); /*writes*/ } fprintf(file,"\n"); /*new line*/ fclose(file); /*done!*/ getchar(); /* pause and wait for key */ //return 0; } the thing is when i compile the code, this what it gives me /home/ugics/st255375/ICS431Labs/Project/Rshell.c: At top level: /home/ugics/st255375/ICS431Labs/Project/Rshell.c:264: warning: conflicting types for ‘writeHistory’ /home/ugics/st255375/ICS431Labs/Project/Rshell.c:217: note: previous implicit declaration of ‘writeHistory’ was here can any one help me??? thanks

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  • Having trouble coming up with a good architecture for a client/server application

    - by rmw1985
    I am writing a remote backup service meant to support 1000+ users. It is going to use librsync to store reverse diffs (like rdiff-backup) and make data transfer efficient. My trouble is that I do not know the "best" way to implement the client/server model. I have thought of doing it like rsync/rdiff-backup do it by having the client open an SSH connection and running a server executable and communicating across pipes. Another alternative would be to write a server which would handle authentication and communicate with the client via SSL. The reason I have thought of this is that there is "state" information like how many backup jobs are setup, etc. that must be maintained. Another alternative that I have thought about is running a "web service" using Pylons or Django to handle the authentication, but I do not know how to bridge that the the "storage" side. Since I am using librsync, I cannot use "dumb" storage. Is there a way to pipe data through Pylons or Django to a server side handler that would do the rsync calculation? This seems to me like maybe a dumb question but I am sort of lost. Any tips or suggestions from more experienced developers would be extremely helpful.

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  • How to avoid loading a LINQ to SQL object twice when editting it on a website.

    - by emzero
    Hi guys I know you are all tired of this Linq-to-Sql questions, but I'm barely starting to use it (never used an ORM before) and I've already find some "ugly" things. I'm pretty used to ASP.NET Webforms old school developing, but I want to leave that behind and learn the new stuff (I've just started to read a ASP.NET MVC book and a .NET 3.5/4.0 one). So here's is one thing I didn't like and I couldn't find a good alternative to it. In most examples of editing a LINQ object I've seen the object is loaded (hitting the db) at first to fill the current values on the form page. Then, the user modify some fields and when the "Save" button is clicked, the object is loaded for second time and then updated. Here's a simplified example of ScottGu NerdDinner site. // // GET: /Dinners/Edit/5 [Authorize] public ActionResult Edit(int id) { Dinner dinner = dinnerRepository.GetDinner(id); return View(new DinnerFormViewModel(dinner)); } // // POST: /Dinners/Edit/5 [AcceptVerbs(HttpVerbs.Post), Authorize] public ActionResult Edit(int id, FormCollection collection) { Dinner dinner = dinnerRepository.GetDinner(id); UpdateModel(dinner); dinnerRepository.Save(); return RedirectToAction("Details", new { id=dinner.DinnerID }); } As you can see the dinner object is loaded two times for every modification. Unless I'm missing something about LINQ to SQL caching the last queried objects or something like that I don't like getting it twice when it should be retrieved only one time, modified and then comitted back to the database. So again, am I really missing something? Or is it really hitting the database twice (in the example above it won't harm, but there could be cases that getting an object or set of objects could be heavy stuff). If so, what alternative do you think is the best to avoid double-loading the object? Thank you so much, Greetings!

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  • C++ Serialization Clean XML Similar to XSTREAM

    - by disown
    I need to write a linux c++ app which saves it settings in XML format (for easy hand editing) and also communicates with existing apps through XML messages over sockets and HTTP. Problem is that I haven't been able to find any intelligent libs to help me, I don't particular feel like writing DOM or SAX code just to write and read some very simple messages. Boost Serialization was almost a match, but it adds a lot of boost-specific data to the xml it generates. This obviously doesn't work well for interchange formats. I'm wondering if it is possible to make Boost Serialization or some other c++ serialization library generate clean xml. I don't mind if there are some required extra attributes - like a version attribute, but I'd really like to be able to control their naming and also get rid of 'features' that I don't use - tracking_level and class_id for instance. Ideally I would just like to have something similar to xstream in Java. I am aware of the fact that c++ lacks introspection and that it is therefore necessary to do some manual coding - but it would be nice if there was a clean solution to just read and write simple XML without kludges! If this cannot be done I am also interested in tools where the XML schema is the canonical resource (contract first) - a good JAXB alternative to C++. So far I have only found commercial solutions like CodeSynthesis XSD. I would prefer open source solutions. I have tried gSoap - but it generates really ugly code and it is also SOAP-specific. In desperation I also started looking at alternative serialization formats for protobuffers. This exists - but only for Java! It really surprises me that protocol buffers seems to be a better supported data interchange format than XML. I'm going mad just finding libs for this app and I really need some new ideas. Anyone?

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  • Authoritative sources about Database vs. Flatfile decision

    - by FastAl
    <tldr>looking for a reference to a book or other undeniably authoritative source that gives reasons when you should choose a database vs. when you should choose other storage methods. I have provided an un-authoritative list of reasons about 2/3 of the way down this post.</tldr> I have a situation at my company where a database is being used where it would be better to use another solution (in this case, an auto-generated piece of source code that contains a static lookup table, searched by binary sort). Normally, a database would be an OK solution even though the problem does not require a database, e.g, none of the elements of ACID are needed, as it is read-only data, updated about every 3-5 years (also requiring other sourcecode changes), and fits in memory, and can be keyed into via binary search (a tad faster than db, but speed is not an issue). The problem is that this code runs on our enterprise server, but is shared with several PC platforms (some disconnected, some use a central DB, etc.), and parts of it are managed by multiple programming units, parts by the DBAs, parts even by mathematicians in another department, etc. These hit their own platform’s version of their databases (containing their own copy of the static data). What happens is that every implementation, every little change, something different goes wrong. There are many other issues as well. I can’t even use a flatfile, because one mode of running on our enterprise server does not have permission to read files (only databases, and of course, its own literal storage, e.g., in-source table). Of course, other parts of the system use databases in proper, less obscure manners; there is no problem with those parts. So why don’t we just change it? I don’t have administrative ability to force a change. But I’m affected because sometimes I have to help fix the problems, but mostly because it causes outages and tons of extra IT time by other programmers and d*mmit that makes me mad! The reason neither management, nor the designers of the system, can see the problem is that they propose a solution that won’t work: increase communication; implement more safeguards and standards; etc. But every time, in a different part of the already-pared-down but still multi-step processes, a few different diligent, hard-working, top performing IT personnel make a unique subtle error that causes it to fail, sometimes after the last round of testing! And in general these are not single-person failures, but understandable miscommunications. And communication at our company is actually better than most. People just don't think that's the case because they haven't dug into the matter. However, I have it on very good word from somebody with extensive formal study of sociology and psychology that the relatively small amount of less-than-proper database usage in this gigantic cross-platform multi-source, multi-language project is bureaucratically un-maintainable. Impossible. No chance. At least with Human Beings in the loop, and it can’t be automated. In addition, the management and developers who could change this, though intelligent and capable, don’t understand the rigidity of this ‘how humans are’ issue, and are not convincible on the matter. The reason putting the static data in sourcecode will solve the problem is, although the solution is less sexy than a database, it would function with no technical drawbacks; and since the sharing of sourcecode already works very well, you basically erase any database-related effort from this section of the project, along with all the drawbacks of it that are causing problems. OK, that’s the background, for the curious. I won’t be able to convince management that this is an unfixable sociological problem, and that the real solution is coding around these limits of human nature, just as you would code around a bug in a 3rd party component that you can’t change. So what I have to do is exploit the unsuitableness of the database solution, and not do it using logic, but rather authority. I am aware of many reasons, and posts on this site giving reasons for one over the other; I’m not looking for lists of reasons like these (although you can add a comment if I've miss a doozy): WHY USE A DATABASE? instead of flatfile/other DB vs. file: if you need... Random Read / Transparent search optimization Advanced / varied / customizable Searching and sorting capabilities Transaction/rollback Locks, semaphores Concurrency control / Shared users Security 1-many/m-m is easier Easy modification Scalability Load Balancing Random updates / inserts / deletes Advanced query Administrative control of design, etc. SQL / learning curve Debugging / Logging Centralized / Live Backup capabilities Cached queries / dvlp & cache execution plans Interleaved update/read Referential integrity, avoid redundant/missing/corrupt/out-of-sync data Reporting (from on olap or oltp db) / turnkey generation tools [Disadvantages:] Important to get right the first time - professional design - but only b/c it's meant to last s/w & h/w cost Usu. over a network, speed issue (best vs. best design vs. local=even then a separate process req's marshalling/netwk layers/inter-p comm) indicies and query processing can stand in the way of simple processing (vs. flatfile) WHY USE FLATFILE: If you only need... Sequential Row processing only Limited usage append only (no reading, no master key/update) Only Update the record you're reading (fixed length recs only) Too big to fit into memory If Local disk / read-ahead network connection Portability / small system Email / cut & Paste / store as document by novice - simple format Low design learning curve but high cost later WHY USE IN-MEMORY/TABLE (tables, arrays, etc.): if you need... Processing a single db/ff record that was imported Known size of data Static data if hardcoding the table Narrow, unchanging use (e.g., one program or proc) -includes a class that will be shared, but encapsulates its data manipulation Extreme speed needed / high transaction frequency Random access - but search is dependent on implementation Following are some other posts about the topic: http://stackoverflow.com/questions/1499239/database-vs-flat-text-file-what-are-some-technical-reasons-for-choosing-one-over http://stackoverflow.com/questions/332825/are-flat-file-databases-any-good http://stackoverflow.com/questions/2356851/database-vs-flat-files http://stackoverflow.com/questions/514455/databases-vs-plain-text/514530 What I’d like to know is if anybody could recommend a hard, authoritative source containing these reasons. I’m looking for a paper book I can buy, or a reputable website with whitepapers about the issue (e.g., Microsoft, IBM), not counting the user-generated content on those sites. This will have a greater change to elicit a change that I’m looking for: less wasted programmer time, and more reliable programs. Thanks very much for your help. You win a prize for reading such a large post!

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  • Replacement for deprecated SQL Server User Defined Type with a bound Rule and Default

    - by Adam Jones
    We have a User Defined Data Type of YesNo which has an which is an alias for char(1). The type has a bound Rule (must be Y or N) and a Default (N). The aim of this is that when any of the development team create a new field of type YesNo the rule and default are automatically bound to the new column. Rules and Defaults have been deprecated and won't be available in the next a future version of SQL Server, is there another way to achieve the same functionality? I should add that I'm aware that I could use CHECK and DEFAULT constraints to replicate the functionality of the bound Rule and Defalut objects, however these would have to be applied at each usage of the type, rather than getting the functionality 'for free' by using a UDT which has a bound Rule and Default. The post relates to a database that backs an existing application, rather than a new development, so I'm aware that our use of UDT's is less than optimal. I suspect the answer to the question is 'No', however normally when features are deprecated there's usually an alternative syntax that can be used as a drop in replacement so I wanted to pose the question in-case someone knew of an alternative.

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  • Is it possible to write map/reduce jobs for Amazon Elastic MapReduce using .NET?

    - by Chris
    Is it possible to write map/reduce jobs for Amazon Elastic MapReduce (http://aws.amazon.com/elasticmapreduce/) using .NET languages? In particular I would like to use C#. Preliminary research suggests not. The above URL's marketing text suggests you have a "choice of Java, Ruby, Perl, Python, PHP, R, or C++", without mentioning .NET languages. This Amazon thread (http://developer.amazonwebservices.com/connect/thread.jspa?messageID=136051 -- "Support for C# / F# map/reducers") explicitly says that "currently Amazon Elastic MapReduce does not support Mono platform or languages such as C# or F#." The above suggests that it can't be done. I'm wondering if there are any workarounds, though. For example, can I modify the Elastic MapReduce machine image for my account, and install Mono on there? An alternative, suggested by Amazon FAQs "Using Other Software Required by Your Jar" (http://docs.amazonwebservices.com/ElasticMapReduce/latest/DeveloperGuide/index.html?CHAP_AdvancedTopics.html) and "How to Use Additional Files and Libraries With the Mapper or Reducer" (http://docs.amazonwebservices.com/ElasticMapReduce/latest/DeveloperGuide/index.html?addl_files.html), is to make the first step of the Map/Reduce job be to install Mono on the local instance. That sounds kind of inefficient, but maybe it could work? Maybe a saner alternative would be to try to forgo the convenience of Elastic MapReduce, and manually set up my own Hadoop cluster on EC2. Then I assume I could install Mono without difficulty.

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