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  • Using static mutex in a class

    - by Dmitry Yudakov
    I have a class that I can have many instances of. Inside it creates and initializes some members from a 3rd party library (that use some global variables) and is not thread-safe. I thought about using static boost::mutex, that would be locked in my class constructor and destructor. Thus creating and destroying instances among my threads would be safe for the 3rd party members. class MyClass { static boost::mutex mx; // 3rd party library members public: MyClass(); ~MyClass(); }; MyClass::MyClass() { boost::mutex::scoped_lock scoped_lock(mx); // create and init 3rd party library stuff } MyClass::~MyClass() { boost::mutex::scoped_lock scoped_lock(mx); // destroy 3rd party library stuff } I cannot link because I receive error: undefined reference to `MyClass::mx` Do I need some special initialization of such static member? Is the whole conception of static mutex wrong?

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  • Android EditText within a ListView

    - by metalideath
    I have created a custom Array Adapter to bind a custom row that contains some static text and an editable EditText. I am trying to register to be notified when the user changes the text within the edit text and when notified to determine which ArrayList row the modified EditText corresponds to. In the past with other types of views such as a Spinner I could simply put a reference to the parent view and the row number into the tag for the Spinner view. And then when I was notified that the value changed I read the tag to determine how to correlate it back to the master ArrayList. The problem with registering to be notifed with an EditText change is that you do not get back a view but instead get a TextWatcher and I have no way to correlate back to the parent view or ArrayList row. What is the technique that you need to use in this circumstance?

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  • accessing required modules from other modules

    - by john smith
    I have a bare-bone express application, exactly the one that is created with the express command. I have installed socket.io and attached it to my server, like this: var app = express(), server = http.createServer(app), io = io.listen(server); server.listen(8000); Now, I also have the routes files, which is called like this: app.get('/', routes.index); Inside this module I have the following function: exports.index = function(req, res){ socket.emit('news', { message: "foo" }); }; This obviously leads to a 500 reference error, because the routes file is an exportable module, and obviously has no idea what the socket is, as it is located in the app.js file. Is there a way I can access this socket object from this, or any other file? Please note that it is attached to the express generated app. extra: what about getting/setting session data? Thanks in advance.

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  • Do you ever feel confident in your skills?

    - by Gary Willoughby
    As a self taught developer i always find myself questioning my skill and knowledge and always feel like i am falling behind in using new technology. Over a period of nearly 9 years i've studied most mainstream languages (especially C based ones), used lots of different OSes, read and absorbed many books and even written one myself. But i still feel i'm usless! Do professional developers ever get to the stage where they feel confident that they know what they are doing and are confident when submitting solutions/code? When do you know you're good enough?

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  • Why are my ActiveRecord class instance variables disappearing after the first request in development

    - by Paul C
    I have a class instance variable on one of my AR classes. I set its value at boot with an initializer and, after that, never touch it again except to read from it. In development mode, this value disappears after the first request to the web server. However, when running tests, using the console or running the production server this does not happen. # The AR class class Group < ActiveRecord::Base class << self attr_accessor :path end end # The initializer Group.path = File.join(RAILS_ROOT, "public", "etc") # First request in a view %p= Group.path #=> "/home/rails/app/public/etc" # Second request in a view %p= Group.path #=> nil Is there something about development mode that nukes instance variables from classes with each request? If so, is there a way to disable this for specific variables or classes?

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  • Optional Fields in Infopath; Getting the xml node with VBA

    - by Sunscreen
    Hi all, I use vb to get data through my form. I have some optional fileds in my form and I have this problem with the following code: MsgBox(myXPathNavigator.SelectSingleNode("/my:Status/my:Questions/my:Questions1", _ Me.NamespaceManager).IsNode.ToString) When the optional filed 'Questions1' is inserted to the form I get the value 'true' by the IsNode function. If the field it is not inserted I have an exception, stating that the reference is not correct (and it is indeed true). Is there a way to verify about a node, whether it is present or not in my form? Thanks in advance, Sun

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  • Is a .Net membership database portable, or are accounts somehow bound to the originating Web site or

    - by Deane
    I have an ASP.Net Web site using .Net Membership with a SQL Server provider, so the users and roles are stored in the SQL tables created by Aspnet_regsql.exe. Is this architecture totally self-contained and portable, or are users in it somehow bound to the specific Web site on which they create their account? Put another way, if we create a bunch of users in dev or UAT, the back up and restore this database to another server, accessed under another domain name, should it still work just fine? We're seeing some odd behavior when we move the database, like users losing group affiliation and such, and I'm curious how portable and environment-agnostic this database really is. I have a sneaking suspicion that something is bound to the machine key or the domain.

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  • Exception Error in c#

    - by Kumu
    using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.IO; using System.Runtime.Serialization.Formatters.Binary; namespace FoolballLeague { public partial class MainMenu : Form { FootballLeagueDatabase footballLeagueDatabase; Game game; Login login; public MainMenu() { InitializeComponent(); changePanel(1); } public MainMenu(FootballLeagueDatabase footballLeagueDatabaseIn) { InitializeComponent(); footballLeagueDatabase = footballLeagueDatabaseIn; } private void Form_Loaded(object sender, EventArgs e) { } private void gameButton_Click(object sender, EventArgs e) { int option = 0; changePanel(option); } private void scoreboardButton_Click(object sender, EventArgs e) { int option = 1; changePanel(option); } private void changePanel(int optionIn) { gamePanel.Hide(); scoreboardPanel.Hide(); string title = "Football League System"; switch (optionIn) { case 0: gamePanel.Show(); this.Text = title + " - Game Menu"; break; case 1: scoreboardPanel.Show(); this.Text = title + " - Display Menu"; break; } } private void logoutButton_Click(object sender, EventArgs e) { login = new Login(); login.Show(); this.Hide(); } private void addGameButton_Click(object sender, EventArgs e) { if ((homeTeamTxt.Text.Length) == 0) MessageBox.Show("You must enter a Home Team"); else if (homeScoreUpDown.Value > 9 || homeScoreUpDown.Minimum < 0) MessageBox.Show("You must enter one digit between 0 and 9"); else if ((awayTeamTxt.Text.Length) == 0) MessageBox.Show("You must enter a Away Team"); else if (homeScoreUpDown.Value > 9 || homeScoreUpDown.Value < 0) MessageBox.Show("You must enter one digit between 0 to 9"); else { //checkGameInputFields(); game = new Game(homeTeamTxt.Text, int.Parse(homeScoreUpDown.Value.ToString()), awayTeamTxt.Text, int.Parse(awayScoreUpDown.Value.ToString())); MessageBox.Show("Home Team -" + '\t' + homeTeamTxt.Text + '\t' + "and" + '\r' + "Away Team -" + '\t' + awayTeamTxt.Text + '\t' + "created"); footballLeagueDatabase.AddGame(game); //clearCreateStudentInputFields(); } } private void timer1_Tick(object sender, EventArgs e) { displayDateAndTime(); } private void displayDateAndTime() { dateLabel.Text = DateTime.Today.ToLongDateString(); timeLabel.Text = DateTime.Now.ToShortTimeString(); } private void displayResultsButton_Click(object sender, EventArgs e) { Game game = new Game(homeTeamTxt.Text, int.Parse(homeScoreUpDown.Value.ToString()), awayTeamTxt.Text, int.Parse(awayScoreUpDown.Value.ToString())); gameResultsListView.Items.Clear(); gameResultsListView.View = View.Details; ListViewItem row = new ListViewItem(); row.SubItems.Add(game.HomeTeam.ToString()); row.SubItems.Add(game.HomeScore.ToString()); row.SubItems.Add(game.AwayTeam.ToString()); row.SubItems.Add(game.AwayScore.ToString()); gameResultsListView.Items.Add(row); } private void displayGamesButton_Click(object sender, EventArgs e) { Game game = new Game("Home", 2, "Away", 4);//homeTeamTxt.Text, int.Parse(homeScoreUpDown.Value.ToString()), awayTeamTxt.Text, int.Parse(awayScoreUpDown.Value.ToString())); modifyGamesListView.Items.Clear(); modifyGamesListView.View = View.Details; ListViewItem row = new ListViewItem(); row.SubItems.Add(game.HomeTeam.ToString()); row.SubItems.Add(game.HomeScore.ToString()); row.SubItems.Add(game.AwayTeam.ToString()); row.SubItems.Add(game.AwayScore.ToString()); modifyGamesListView.Items.Add(row); } } } This is the whole code and I got same error like previous question. Unhandled Exception has occurred in you application.If you click...............click Quit.the application will close immediately. Object reference not set to an instance of an object. And the following details are in the error message. ***** Exception Text ******* System.NullReferenceException: Object reference not set to an instance of an object. at FoolballLeague.MainMenu.addGameButton_Click(Object sender, EventArgs e) in C:\Users\achini\Desktop\FootballLeague\FootballLeague\MainMenu.cs:line 91 at System.Windows.Forms.Control.OnClick(EventArgs e) at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent) at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.ButtonBase.WndProc(Message& m) at System.Windows.Forms.Button.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) I need to add the games to using the addGameButton and the save those added games and display them in the list view (gameResultsListView). Now I can add a game and display in the list view.But when I pressed the button addGameButton I got the above error message. If you can please give me a solution to this problem.

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  • Using C# Type as generic

    - by I Clark
    I'm trying to create a generic list from a specific Type that is retrieved from elsewhere: Type listType; // Passed in to function, could be anything var list = _service.GetAll<listType>(); However I get a build error of: The type or namespace name 'listType' could not be found (are you missing a using directive or an assembly reference?) Is this even possible or am I setting foot onto C# 4 Dynamic territory? As a background: I want to automatically load all lists with data from the repository. The code below get's passed a Form Model whose properties are iterated for any IEnum (where T inherits from DomainEntity). I want to fill the list with objects of the Type the list made of from the repository. public void LoadLists(object model) { foreach (var property in model.GetType() .GetProperties(BindingFlags.Public | BindingFlags.Instance | BindingFlags.SetProperty)) { if (IsEnumerableOfNssEntities(property.PropertyType)) { var listType = property.PropertyType.GetGenericArguments()[0]; var list = _repository.Query<listType>().ToList(); property.SetValue(model, list, null); } } }

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  • Migrating a Core Data Store from iCloud to local

    - by schmok
    I'm currently struggling with Core Data iCloud migration. I want to move a store from an iCloud ubiquity container (.nosync) to a local URL. Problem is whenever I call something like this: NSPersistentStore *newStore = [self.persistentStoreCoordinator migratePersistentStore: currentiCloudStore toURL: localURL options: nil withType: NSSQLiteStoreType error: &error]; I get this error: -[NSPersistentStoreCoordinator addPersistentStoreWithType:configuration:URL:options:error:](1055): CoreData: Ubiquity: Error: A persistent store which has been previously added to a coordinator using the iCloud integration options must always be added to the coordinator with the options present in the options dictionary. If you wish to use the store without iCloud, migrate the data from the iCloud store file to a new store file in local storage. file://localhost/Users/sch/Library/Containers/bla/Data/Documents/tmp.sqlite. This will be a fatal error in a future release Anyone ever seen this error? Maybe I'm just missing the right migration options?

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  • Is it better to comment out unneeded code or delete it?

    - by Matt Connolly
    For web applications under maintenance, assuming you have source control, when you need to remove part of the UI and the associated code, do you delete the code and check in, or do you comment out the old code? Arguments in favor of deleting: cleaner code, can still see deleted code in source control history, no worrying about refactoring code that might be uncommented some day. Arguments in favor of commenting: sometimes you need to add the feature back in and the developer adding it back in may not know to check source control history, sometimes the code represents unique functionality that can be a handy reference, seeing it all in one place can help provide clues to deciphering the active code.

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  • What is the worst class/variable/function name you have ever encountered

    - by Chris Noe
    Naming things well is arguably Job 1 for professional programmers. Yet we have all suffered from some bad naming choices from time to time. So just to vent a little, what are some doozies that you may have run across? Just to get things started: One of our original developers wasn't sure what to call a secondary key - on what turned out to be a primary table for this app - so he called it: DL2WhateverTheHellThatIs. Unfortunately this system generates entity mappings from the XML, and attributes defined there result in classes, methods, and constants that are referenced through-out the app. To this day it is very hard to find a source file that does not reference this, er, thing! A few actual examples: DL2WhateverTheHellThatIsBean cos = (DL2WhateverTheHellThatIsBean)itr.next(); String code = getDL2WhateverTheHellThatIs().getCode(); From from = new From("DL2WhateverTheHellThatIs"); String filter = "_dL2WhateverTheHellThatIs._code"; (Very difficult to refactor)

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  • Using setSourceType with image picker up hides status bar

    - by Aaron
    I am pretty sure this is a bug but I thought I would check. I used the camera overlay to add a button so that on the iphone a user can switch from the camera view to the photo library. When button is taped the source type switches fine but the status bar is missing from the photo library. Throughout the rest of that session the status bar remains missing from all views evet thougth isStatusBarHidden reports NO. This is how the camera overlay view is created if (cameraOverlayView == nil) { [[NSBundle mainBundle] loadNibNamed:@"CameraOverlayView" owner:self options:nil]; } If camera is available this is when I set source type and add overlay if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) { [imagePicker setSourceType:UIImagePickerControllerSourceTypeCamera]; [imagePicker setCameraOverlayView:cameraOverlayView]; } Here is the action statement to change source type. (IBAction)selectImage; { [imagePicker setSourceType:UIImagePickerControllerSourceTypePhotoLibrary]; } If I don't tap the button on the overlay there is no problem with the status bar. PS. I did submit a bug report on this.

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  • UIScrollView: Is 806k Image too much too handle? (Crash, out of memory)?

    - by Jordan
    I'm loading a 2400x1845 png image into a scroll view. The program crashes out of memory, is there a better way to handle this? mapScrollView is an UIScrollView in IB, along with a couple of UIButtons. -(void)loadMapWithName:(NSString *)mapName { NSString* bundlePath = [[NSBundle mainBundle] bundlePath]; UIImage *image = [UIImage imageWithContentsOfFile:[NSString stringWithFormat:@"%@/path/%@", bundlePath, [maps objectForKey:mapName]]]; UIImageView *imageView = [[UIImageView alloc] initWithImage:image]; CGSize imgSize = image.size; mapScrollView.contentSize = imgSize; [mapScrollView addSubview:imageView]; [imageView release]; [self.view addSubview:mapScrollView]; }

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  • Is this a valid jquery getJSON call?

    - by Pandiya Chendur
    I am using jquery getJSON with asp.net mvc controller... I cant able to get it work.... public JsonResult GetMaterials(int currentPage,int pageSize) { var materials = consRepository.FindAllMaterials().AsQueryable(); var results = new PagedList<MaterialsObj>(materials, currentPage-1, pageSize); return Json(results); } and i am calling this with, $.getJSON('Materials/GetMaterials', "{'currentPage':1,'pageSize':5}", function(data) { }); This call doesn't seem to work.... when inspected through firebug i found this, The parameters dictionary contains a null entry for parameter 'currentPage' of non-nullable type 'System.Int32' for method 'System.Web.Mvc.JsonResult GetMaterials(Int32, Int32)' in 'CrMVC.Controllers.MaterialsController'. To make a parameter optional its type should be either a reference type or a Nullable type.<br> Parameter name: parameters

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  • datatable works in C# winform but not ASP.NET

    - by Charles Gargent
    Hi I have created a class that returns a datatable, when I use the class in a c# winform the dataGridView is populted corectly using the following code dataGridView1.DataSource = dbLib.GetData(); However when I try the same thing with ASP.NET I get a Object reference not set to an instance of an object. using the following code GridView1.DataSource = dbLib.GetData(); GridView1.DataBind(); What am I doing wrong / missing Thanks EDIT for the curios here is the dbLib class public static DataTable GetData() { SQLiteConnection cnn = new SQLiteConnection("Data Source=c:\\test.db"); SQLiteCommand cmd = new SQLiteCommand("SELECT count(Message) AS Occurances, Message FROM evtlog GROUP BY Message ORDER BY Occurances DESC LIMIT 25", cnn); cnn.Open(); SQLiteDataReader dr = cmd.ExecuteReader(CommandBehavior.CloseConnection); DataTable dt = new DataTable(); dt.Load(dr); return dt; }

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  • How to index a string like "aaa.bbb.ddd-fff" in Lucene?

    - by user46703
    Hi, I have to index a lot documents that contain reference numbers like "aaa.bbb.ddd-fff". The structure can change but it's always some arbitrary numbers or characters combined with "/","-","_" or some other delimiter. The users want to be able to search for any of the substrings like "aaa" or "ddd" and also for combinations like "aaa.bbb" or "ddd-fff". The best I have been able to come up with is to create my own token filter modeled after the synonym filter in "Lucene in action" which spits out multiple terms for each input. In my case I return "aaa.bbb", "bbb.ddd","bbb.ddd-fff" and all other combinations of the substrings. This works pretty well but when I index large documents (100MB) that contain lots of such strings I tend to get out of memory exceptions because my filter returns multiple terms for each input string. Is there a better way to index these strings?

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  • Filter zipcodes by proximity in Django with the Spherical Law of Cosines

    - by spiffytech
    I'm trying to handle proximity search for a basic store locater in Django. Rather than haul PostGIS around with my app just so I can use GeoDjango's distance filter, I'd like to use the Spherical Law of Cosines distance formula in a model query. I'd like all of the calculations to be done in the database in one query, for efficiency. An example MySQL query from The Internet implementing the Spherical Law of Cosines like this: SELECT id, ( 3959 * acos( cos( radians(37) ) * cos( radians( lat ) ) * cos( radians( lng ) - radians(-122) ) + sin( radians(37) ) * sin( radians( lat ) ) ) ) AS distance FROM stores HAVING distance < 25 ORDER BY distance LIMIT 0 , 20; The query needs to reference the Zipcode ForeignKey for each store's lat/lng values. How can I make all of this work in a Django model query?

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  • Using nodereference + views to create combined view

    - by Ian Silber
    I'm trying to set up a relational View but not sure how to do it. Here's an example of what I'm going for using the node types Artist and Song. Artist Song Length Bob Dylan Like a Rolling Stone 2:00 Bruce Springsteen Atlantic City 4:00 Burce Springsteen Born to Run 5:24 Van Morrison Domino 3:22 Van Morrison Brown Eyed Girl 4:30 Assuming I have an Artist node type that has a node reference to Song (set to unlimited) and a Song data type with an additional field for length, how would I go about configuring the view to output this view? Thanks! Ian

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  • How can I isolate the form controls in a ASP Web User Control from the rest of the page's form contr

    - by Justin808
    I have a Web User Control I created for authentication. The web user control is inside the box below. Clicking any button (1 or 2) below works correct as it goes to the correct c# button click event in the code behind file. If I press enter on fields a or b it goes to the correct callback (button1's) if I press enter on field c it still goes to button1's callback, not button2's How can I give my web user control a nice self contained for and view state etc, so it wont mess with the remainder of the page's form? +--------------+ | User: __a___ | | Pass: __b___ | | [button1]| +--------------+ Prompt:______c______ [button2]

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  • Why is floating point byte swapping different from integer byte swapping?

    - by CJ
    I have a binary file of doubles that I need to load using C++. However, my problem is that it was written in big-endian format but the fstream operator will then read the number wrong because my machine is little-endian. It seems like a simple problem to resolve for integers, but for doubles and floats the solutions I have found won't work. How can I (or should I) fix this? I read this as a reference for integer byte swapping: http://stackoverflow.com/questions/105252/how-do-i-convert-between-big-endian-and-little-endian-values-in-c

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  • Change cell color in Excel according to adjacent dropdown value

    - by Andrew Heath
    I understand how to make a dropdown list. I understand how to make conditional formatting change the color of a cell. What I do not understand is how to make conditional formatting change the color of a cell based solely on the state of another cell (not a comparison). A1 is a No / Yes dropdown list B1 is a criteria statement If the user satisfies the criteria statement in B1, they select Yes on the dropdown list in A1. For quick reference, if possible, I'd like B1 to change to a green background color on this event... and of course change back to no-fill if the dropdown is reset to No. Is this possible in Excel 2003 and/or 2007?

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  • Using TTSearchBar with TTThumbsViewController

    - by scompt.com
    I would like to layout a TTSearchBar above above a TTThumbsViewController. My current (failing) attempt involves my own SearchViewController that inherits from TTViewController and contains a reference to a TTThumbsViewController and TTSearchBar. In the loadView method, I instantiate both TTThumbsViewController and TTSearchBar and add them (actually, ..the view property of the TTTVC) as subviews. When the SearchViewController is pushed, neither the TTThumbsViewController nor the TTSearchBar are displayed. Am I going about this wrong? Is there a better way to add search to the TTThumbsViewController?

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  • How can I catch runtime error in C++

    - by Yan Cheng CHEOK
    By referring to http://stackoverflow.com/questions/315948/c-catching-all-exceptions try { int i = 0; int j = 0/i; /* Division by 0 */ int *k = 0; std::cout << *k << std::endl; /* De-reference invalid memory location. */ } catch (...) { std::cout << "Opps!" << std::endl; } The above run-time error are unable to be detected. Or, am I having wrong expectation on C++ exception handling feature?

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  • Creating an Extremely Large Index in Oracle

    - by Rudiger
    Can someone look at the linked reference and explain to me the precise statements to run? Oracle DBA's Guide: Creating a Large Index Here's what I came up with... CREATE TEMPORARY TABLESPACE ts_tmp TEMPFILE 'E:\temp01.dbf' SIZE 10000M REUSE AUTOEXTEND ON EXTENT MANAGEMENT LOCAL; ALTER USER me TEMPORARY TABLESPACE ts_tmp; CREATE UNIQUE INDEX big_table_idx ON big_table ( record_id ); DROP TABLESPACE ts_tmp; Edit 1 After this index was created, I ran an explain plan for a simple query and get this error: ORA-00959: tablespace 'TS_TMP' does not exist It seems like it's not temporary at all... :(

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