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  • What is the fastest way to insert 100 000 records from one database to another?

    - by Pentium10
    I have a mobile application. My client has a large data set ~100.000 records. It's updated frequently. When we sync we need to copy from one database to another. I have attached the second database to the main, and run an insert into table select * from sync.table. This is extremely slow, it takes about 10 minutes I think. I noticed that the journal file gets increased step by step. How can I speed this up? EDITED 1 I have indexes off, and I have journal off. Using insert into table select * from sync.table it still takes 10 minutes. EDITED 2 If I run a query like select id,invitem,invid,cost from inventory where itemtype = 1 order by invitem limit 50 it takes 15-20 seconds. The table schema is: CREATE TABLE inventory ('id' INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, 'serverid' INTEGER NOT NULL DEFAULT 0, 'itemtype' INTEGER NOT NULL DEFAULT 0, 'invitem' VARCHAR, 'instock' FLOAT NOT NULL DEFAULT 0, 'cost' FLOAT NOT NULL DEFAULT 0, 'invid' VARCHAR, 'categoryid' INTEGER DEFAULT 0, 'pdacategoryid' INTEGER DEFAULT 0, 'notes' VARCHAR, 'threshold' INTEGER NOT NULL DEFAULT 0, 'ordered' INTEGER NOT NULL DEFAULT 0, 'supplier' VARCHAR, 'markup' FLOAT NOT NULL DEFAULT 0, 'taxfree' INTEGER NOT NULL DEFAULT 0, 'dirty' INTEGER NOT NULL DEFAULT 1, 'username' VARCHAR, 'version' INTEGER NOT NULL DEFAULT 15 ) Indexes are created like CREATE INDEX idx_inventory_categoryid ON inventory (pdacategoryid); CREATE INDEX idx_inventory_invitem ON inventory (invitem); CREATE INDEX idx_inventory_itemtype ON inventory (itemtype); I am wondering, the insert into ... select * from isn't the fastest built-in way to do massive data copy? EDITED 3 SQLite is serverless, so please stop voting a particular answer, because that is not the answer I'm sure.

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  • lambda expressions in VB.NET... what am I doing wrong???

    - by Bob
    when I run this C# code, no problems... but when I translate it into VB.NET it compiles but blows due to 'CompareString' member not being allowed in the expression... I feel like I'm missing something key here... private void PrintButton_Click(object sender, EventArgs e) { if (ListsListBox.SelectedIndex > -1) { //Context using (ClientOM.ClientContext ctx = new ClientOM.ClientContext(UrlTextBox.Text)) { //Get selected list string listTitle = ListsListBox.SelectedItem.ToString(); ClientOM.Web site = ctx.Web; ctx.Load(site, s => s.Lists.Where(l => l.Title == listTitle)); ctx.ExecuteQuery(); ClientOM.List list = site.Lists[0]; //Get fields for this list ctx.Load(list, l => l.Fields.Where(f => f.Hidden == false && (f.CanBeDeleted == true || f.InternalName == "Title"))); ctx.ExecuteQuery(); //Get items for the list ClientOM.ListItemCollection listItems = list.GetItems( ClientOM.CamlQuery.CreateAllItemsQuery()); ctx.Load(listItems); ctx.ExecuteQuery(); // DOCUMENT CREATION CODE GOES HERE } MessageBox.Show("Document Created!"); } } but in VB.NET code this errors due to not being allowed 'CompareString' members in the ctx.Load() methods... Private Sub PrintButton_Click(sender As Object, e As EventArgs) If ListsListBox.SelectedIndex > -1 Then 'Context Using ctx As New ClientOM.ClientContext(UrlTextBox.Text) 'Get selected list Dim listTitle As String = ListsListBox.SelectedItem.ToString() Dim site As ClientOM.Web = ctx.Web ctx.Load(site, Function(s) s.Lists.Where(Function(l) l.Title = listTitle)) ctx.ExecuteQuery() Dim list As ClientOM.List = site.Lists(0) 'Get fields for this list ctx.Load(list, Function(l) l.Fields.Where(Function(f) f.Hidden = False AndAlso (f.CanBeDeleted = True OrElse f.InternalName = "Title"))) ctx.ExecuteQuery() 'Get items for the list Dim listItems As ClientOM.ListItemCollection = list.GetItems(ClientOM.CamlQuery.CreateAllItemsQuery()) ctx.Load(listItems) ' DOCUMENT CREATION CODE GOES HERE ctx.ExecuteQuery() End Using MessageBox.Show("Document Created!") End If End Sub

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  • WPF binding comboboxes to parent- child model

    - by PaulB
    I've got a model with a few tiers in it - something along the lines of ... Company Employees Phone numbers So I've got a ListBox showing all the companys in the model. Each ListBoxItem then contains two comboboxes ... one for employees, one for phone numbers. I can successfully get the employee combo to bind correctly and show the right people, but I'd like the phone combo to show the numbers for the selected employee. I'm just setting the DataContext of the ListBox to the model above and using the following data template for each item <DataTemplate x:Key="CompanyBody"> <StackPanel Orientation="Horizontal"> <Label Content="{Binding Path=CompanyName}"></Label> <ComboBox Name="EmployeesCombo" ItemsSource="{Binding Path=Company.Employees}"></ComboBox> <!-- What goes here --> <ComboBox DataContext="???" ItemsSource="??" ></ComboBox> </StackPanel> </DataTemplate> I've tried (naively) <ComboBox ItemsSource="{Binding Path=Company.Employees.PhoneNumbers}" ></ComboBox> and <ComboBox DataContext="EmployeesCombo.SelectedValue" ItemsSource="{Binding Path=PhoneNumbers}" ></ComboBox> and all other manner of combinations ...

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  • explain notifier.c from the Linux kernel

    - by apollon
    I'm seeking to fully understand the following code snippet from kernel/notifier.c. I have read and built simple link lists and think I get the construct from K&R's C programming. The second line below which begins with the 'int' appears to be two items together which is unclear. The first is the (*notifier_call) which I believe has independent but related significance with the second containing a 'notifier block' term. Can you explain how it works in detail? I understand that there is a function pointer and multiple subscribers possible. But I lack the way to tie these facts together, and could use a primer or key so I exactly understand how the code works. The third line looks to contain the linking structure, or recursive nature. Forgive my terms, and correct them as fit as I am a new student of computer science terminology. struct notifier_block { int (*notifier_call)(struct notifier_block *, unsigned long, void *); struct notifier_block *next; int priority; };

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  • mysql query not running correctly from inside the application

    - by Mala
    I am completely stumped. Here is my php (CodeIgniter) code: function mod() { $uid = $this->session->userdata('uid'); $pid = $this->input->post('pid'); if ($this->_verify($uid,$pid)) { $name = $this->input->post('name'); $price = $this->input->post('price'); $curr = $this->input->post('curr'); $url = $this->input->post('url'); $query = $this->db->query("UPDATE items SET name=".$this->db->escape($name).", price=".$this->db->escape($price).", currency=".$this->db->escape($curr),", url=".$this->db->escape($url)." WHERE pid=".$this->db->escape($pid)." LIMIT 1"); } header('location: '.$this->session->userdata('current')); } The purpose of this code is to modify the properties (name, price, currency, url) of a row in the 'items' table (priary key is pid). However, for some reason, allowing this function to run once modifies the name, price, currency and url of ALL entries in the table, regardless of their pid and of the LIMIT 1 thing I tacked on the end of the query. It's as if the last line of the query is being completely ignored. As if this wasn't strance enough, I replaced "$query = $this->db->query(" with an "echo" to see the SQL query being run, and it outputs a query much like I would expect: UPDATE items SET name='newname', price='newprice', currency='newcurrency', url='newurl' WHERE pid='10' LIMIT 1 Copy-pasting this into a MySQL window acts exactly as I want: it modifies the row with the selected pid. What is going on here???

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  • Syntax for finding structs in multisets - C++

    - by Sarah
    I can't seem to figure out the syntax for finding structs in containers. I have a multiset of Event structs. I'm trying to find one of these structs by searching on its key. I get the compiler error commented below. struct Event { public: bool operator < ( const Event & rhs ) const { return ( time < rhs.time ); } bool operator > ( const Event & rhs ) const { return ( time > rhs.time ); } bool operator == ( const Event & rhs ) const { return ( time == rhs.time ); } double time; int eventID; int hostID; int s; }; typedef std::multiset< Event, std::less< Event > > EventPQ; EventPQ currentEvents; double oldRecTime = 20.0; EventPQ::iterator ceItr = currentEvents.find( EventPQ::key_type( oldRecTime ) ); // no matching function call I've tried a few permutations to no avail. I thought defining the conditional equality operator was going to be enough.

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  • Should core application configuration be stored in the database, and if so what should be done to se

    - by Rl
    I'm writing an application around a lot of hierarchical data. Currently the hierarchy is fixed, but it's likely that new items will be added to the hierarchy in the future. (please let them be leaves) My current application and database design is fairly generic and nothing dealing with specific nodes in the hierarchy is hardcoded, with the exception of validation and lookup functions written to retrieve external data from each node's particular database. This pleases me from a design point of view, but I'm nervous at the realization that the entire application rests on a handful of records in the database. I'm also frustrated that I have to enforce certain aspects of data integrity with database triggers rather than by foreign key constraints (an example is where several different nodes in the hierarchy have their own proprietary IDs and I store them in a single column which, when coupled with the node ID can be used to locate the foreign data). I'm starting to wonder whether it may have been appropriate to simply hardcoded these known nodes into the system so that it would be more "type safe" and less generic. How does one know when something should be hardcoded, and when it should be a configuration item? Is it just a cost-benefit analysis of clarity/safety now vs less work later, or am I missing some metric I should be using to determine whether or not this is appropriate. The steps I'm taking to protect these valuable configurations are to add triggers that prevent updates/deletes. The database user that this application uses will only have the ability to manipulate data through stored procedures. What else can I do?

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  • Spreadsheet_Excel_Writer large data output is damaged

    - by dr3w
    I use Spreadsheet_Excel_Writer to generate .xls file and it works fine until I have to deal with a large amount of data. On certain stage it just writes some nonsense chars and quits filling certain columns. However some columns are field up to the end (generally numeric data) I'm not quite sure how the xls document is formed: row by row, or col by col... Also it is obviously not an error in a string, because when i cut out some data, the error appears a little bit further. I think there is no need in all of my code here are some essentials $filename = 'file.xls'; $workbook = & new Spreadsheet_Excel_Writer(); $workbook->setVersion(8); $contents =& $workbook->addWorksheet('Logistics'); $contents->setInputEncoding('UTF-8'); $workbook->send($filename); //here is the part where I write data down $contents->write(0, 0, 'Field A'); $contents->write(0, 1, 'Field B'); $contents->write(0, 2, 'Field C'); $ROW=1; foreach($ordersArr as $key=>$val){ $contents->write($ROW, 0, $val['a']); $contents->write($ROW, 1, $val['b']); $contents->write($ROW, 2, $val['c']); $ROW++; } $workbook->close();

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  • Hibernate saveOrUpdate problem on char data type

    - by Yashwant Chavan
    Hi I am using Hibernate 3.0 , facing issue related to the char datatype field. I am trying to save Client pojo in the database, using following method. Problem is my client_id field is char(10) in the database. when client_id is 10 characters it works fine. but when client_id is less than ten characters it gives problem at the time of update. Rather than updating data it try to insert cleint record again and gives the unquie key exeception. i drill down the problem because of char(10) client_id field. it keeps space after client_id value upto 10 characters. Is there is any confuguration to overcome this problem. rather than modifying client_id to varchar2. public boolean saveClient(Clnt client) { boolean lReturnValue = false; SessionFactory sessionFactory = null; Session session = null; Transaction transaction = null; try { HibernateTemplate hibernateTemplate = getHibernateTemplate(); sessionFactory = hibernateTemplate.getSessionFactory(); session = sessionFactory.getCurrentSession(); transaction = session.beginTransaction(); session.saveOrUpdate(client); transaction.commit(); lReturnValue = true; } catch (HibernateException e) { lReturnValue = false; // TODO Auto-generated catch block if (transaction != null) { transaction.rollback(); } e.printStackTrace(); } return lReturnValue; }

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  • Dom Traversal to Automate Keyboard Focus - Spatial Navigation

    - by Steve
    I'm going to start with a little background that will hopefully help my question make more sense. I am developing an application for a television. The concept is simple and basically works by overlaying a browser over the video plane of the TV. Now being a TV, there is no mouse or additional pointing device. All interaction is done through a remote control. Therefore, the user needs to be able to visually tell which element they are currently focused upon. To indicate that an element is focused, I currently append a colored transparent image over the element to indicate focus. Now, when a user hits the arrow keys, I need to respond by focusing on the correct elements according to the key pressed. So, if the down arrow is pressed I need to focus on the next focusable element in the DOM tree (which may be a child or sibling), and if they hit the up arrow, I need to respond to the previous element. This would essentially simulate spatial navigation within a browser. I am currently setting an attribute (focusable=true) on any DOM elements that should be able to receive focus. What I would like to do is determine the previous or next focusable element (i.e. attribute focusable=true) and apply focus to the element. I was hoping to traverse the DOM tree to determine the next and previously focusable elements, but I am not sure how to perform this in JQuery, or in general. I was leaning towards trying to use the JQuery tree travesal methods like next(), prev(), etc. What approach would you take to solve this type of issue? Thanks

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  • How to reset keyboard for an entry field?

    - by David.Chu.ca
    I am using tag field as a flag for text fields text view fields for auto-jumping to the next field: - (BOOL)findNextEntryFieldAsResponder:(UIControl *)field { BOOL retVal = NO; for (UIView* aView in mEntryFields) { if (aView.tag == (field.tag + 1)) { [aView becomeFirstResponder]; retVal = YES; break; } } return retVal; } It works fine in terms of auto-jumping to the next field when Next key is pressed. However, my case is that the keyboards are different some fields. For example, one fields is numeric & punctuation, and the next one is default (alphabetic keys). For the numeric & punctuation keyboard is OK, but the next field will stay as the same layout. It requires user to press 123 to go back ABC keyboard. I am not sure if there is any way to reset the keyboard for a field as its keyboard defined in xib? Not sure if there is any APIs available? I guess I have to do something is the following delegate? -(void)textFieldDidBegingEditing:(UITextField*) textField { // reset to the keyboard to request specific keyboard view? .... } OK. I found a solution close to my case by slatvik: -(void) textFieldDidBeginEditing:(UITextField*) textField { textField.keyboardType = UIKeybardTypeAlphabet; } However, in the case of the previous text fields is numeric, the keyboard stays numeric when auto-jumped to the next field. Is there any way to set keyboard to alphabet mode?

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  • PHP 5.3 and interface \ArrayAccess

    - by Jakub Lédl
    I'm now working on a project and I have one class that implements the ArrayAccess interface. Howewer, I'm getting an error that says that my implementation: must be compatible with that of ArrayAccess::offsetSet(). My implementation looks like this: public function offsetSet($offset, $value) { if (!is_string($offset)) { throw new \LogicException("..."); } $this->params[$offset] = $value; } So, to me it looks like my implementation is correct. Any idea what is wrong? Thanks very much! The class look like this: class HttpRequest implements \ArrayAccess { // tons of private variables, methods for working // with current http request etc. Really nothing that // could interfere with that interface. // ArrayAccess implementation public function offsetExists($offset) { return isset ($this->params[$offset]); } public function offsetGet($offset) { return isset ($this->params[$offset]) ? $this->params[$offset] : NULL; } public function offsetSet($offset, $value) { if (!is_string($offset)) { throw new \LogicException("You can only assing to params using specified key."); } $this->params[$offset] = $value; } public function offsetUnset($offset) { unset ($this->params[$offset]); } }

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  • DataTrigger not reevaluating after property changes

    - by frozen
    I have a listbox which has its itemssource (this is done in the code behind on as the window is created) databound to an observable collection. The List box then has the following data template assigned against the items: usercontrol.xaml ... <ListBox x:Name="communicatorListPhoneControls" ItemContainerStyle="{StaticResource templateForCalls}"/> ... app.xaml ... <Style x:Key="templateForCalls" TargetType="{x:Type ListBoxItem}"> <Setter Property="ContentTemplate" Value="{StaticResource templateRinging}"/> <Style.Triggers> <DataTrigger Binding="{Binding Path=hasBeenAnswered}" Value="True"> <Setter Property="ContentTemplate" Value="{StaticResource templateAnswered}"/> </DataTrigger> </Style.Triggers> </Style> ... When the observable collection is updated with an object, this appears in the listbox with the correct initial datatemplate, however when the "hasBeenAnswered" property is set to true (when debugging i can see the collection is correct) the datatrigger does not re-evaluate and then update the listbox to use the correct data template. I have implemented the INotifyPropertyChanged Event in my object, and if in the template i bind to a value, i can see the value update. Its just that the datatrigger will not re-evaluate and change to the correct template. I know the datatrigger binding is correct because if i close the window and open it again, it will correctly apply the second datatemplate, because the "hasBeenAnswered" is set to True.

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  • I've registered my oath about 5 times now, but... (twitteR package R)

    - by user2985989
    I'm attempting to mine twitter data in R, and am having trouble getting started. I created a twitter account, an app in twitter developers, changed the settings to read, write, and access, created my access token, and followed instructions to the letter in registering it: My code: > library(twitteR) > download.file(url="http://curl.haxx.se/ca/cacert.pem", + destfile="cacert.pem") > requestURL <- "https://api.twitter.com/oauth/request_token" > accessURL <- "https://api.twitter.com/oauth/access_token" > authURL <- "https://api.twitter.com/oauth/authorize" > consumerKey <-"my key" #took this part out for privacy's sake > consumerSecret <- "my secret" #this too > twitCred <- OAuthFactory$new(consumerKey=consumerKey, consumerSecret = consumerSecret, requestURL = requestURL, accessURL = accessURL, authURL = authURL) > twitCred$handshake(cainfo="cacert.pem") To enable the connection, please direct your web browser to: https://api.twitter.com/oauth/authorize?oauth_token=zxgHXJkYAB3wQ2IVAeyJjeyid7WK6EGPfouGmlx1c When complete, record the PIN given to you and provide it here: 0010819 > registerTwitterOAuth(twitCred) [1] TRUE > save(list="twitCred", file="twitteR_credentials") And yet, this: > s <- searchTwitter('#United', cainfo="cacert.pem") [1] "Unauthorized" Error in twInterfaceObj$doAPICall(cmd, params, "GET", ...) : Error: Unauthorized I'm about to have a temper tantrum. I'd be extremely grateful if someone could explain to me what is going wrong, or, better yet, how to fix it. Thank you.

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  • Looping Through Database Query

    - by DrakeNET
    I am creating a very simple script. The purpose of the script is to pull a question from the database and display all answers associated with that particular question. We are dealing with two tables here and there is a foreign key from the question database to the answer database so answers are associated with questions. Hope that is enough explanation. Here is my code. I was wondering if this is the most efficient way to complete this or is there an easier way? <html> <head> <title>Advise Me</title> <head> <body> <h1>Today's Question</h1> <?php //Establish connection to database require_once('config.php'); require_once('open_connection.php'); //Pull the "active" question from the database $todays_question = mysql_query("SELECT name, question FROM approvedQuestions WHERE status = active") or die(mysql_error()); //Variable to hold $todays_question aQID $questionID = mysql_query("SELECT commentID FROM approvedQuestions WHERE status = active") or die(mysql_error()); //Print today's question echo $todays_question; //Print comments associated with today's question $sql = "SELECT commentID FROM approvedQuestions WHERE status = active"; $result_set = mysql_query($sql); $result_num = mysql_numrows($result_set); for ($a = 0; $a < $result_num; $a++) { echo $sql; } ?> </body> </html>

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  • compile c problem in emacs (ubuntu)

    - by user565739
    I wrote a very simple program like: ( sorry, I typed the code in the right way, but the display is wired. How could I fix it?) #include <stdio.h> int main( void ) { int i; for ( i = 0; i <= 10; i++ ) { printf( "%d hello!\n", i); } return 0; } Usually, I compile c program in terminal with the command cc -o xxx xxx.c So in Emacs, when I type M-x compile, I change make -k to cc -o. But I got error like cc: argument to '-o' is missing What's the problem? If I use make, then I still got error No targets specified and no makefiles found. Finally, if the above problem is fixed, how could I define a custom hotkey for compile? I have already know how to do something like global-set-key [f8] 'goto-line But I don't know to set a hotkey for an action only for c-mode.

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  • Iterate over defined elements of a JS array

    - by sibidiba
    I'm using a JS array to Map IDs to actual elements, i.e. a key-value store. I would like to iterate over all elements. I tried several methods, but all have its caveats: for (var item in map) {...} Does iterates over all properties of the array, therefore it will include also functions and extensions to Array.prototype. For example someone dropping in the Prototype library in the future will brake existing code. var length = map.lenth; for (var i = 0; i < length; i++) { var item = map[i]; ... } does work but just like $.each(map, function(index, item) {...}); They iterate over the whole range of indexes 0..max(id) which has horrible drawbacks: var x = []; x[1]=1; x[10]=10; $.each(x, function(i,v) {console.log(i+": "+v);}); 0: undefined 1: 1 2: undefined 3: undefined 4: undefined 5: undefined 6: undefined 7: undefined 8: undefined 9: undefined 10: 10 Of course my IDs wont resemble a continuous sequence either. Moreover there can be huge gaps between them so skipping undefined in the latter case is unacceptable for performance reasons. How is it possible to safely iterate over only the defined elements of an array (in a way that works in all browsers and IE)?

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  • Lack of understanding crash report

    - by Alan Lai
    I have this crash report. Incident Identifier: CA9E350A-C842-4349-AAD8-E9E62E93BDD1 CrashReporter Key: 360bc129d2f79a48e291eb5ca38b24e822ed5b6b Hardware Model: xxx Process: OrientalDailyiOS [1502] Path: /var/mobile/Applications/39480A57-68FF-4C46-8445-340EFE204119/OrientalDailyiOS.app/OrientalDailyiOS Identifier: OrientalDailyiOS Version: ??? (???) Code Type: ARM (Native) Parent Process: launchd [1] Date/Time: 2012-10-14 15:49:10.884 -0700 OS Version: iOS 6.0 (10A403) Report Version: 104 Exception Type: EXC_CRASH (SIGABRT) Exception Codes: 0x0000000000000000, 0x0000000000000000 Crashed Thread: 0 Last Exception Backtrace: 0 CoreFoundation 0x37a0a29e __exceptionPreprocess + 158 1 libobjc.A.dylib 0x34e3197a objc_exception_throw + 26 2 CoreFoundation 0x37955b70 -[__NSArrayM objectAtIndex:] + 160 3 OrientalDailyiOS 0x00064fdc -[Main_NewsDetail viewDidLoad] (Main_NewsDetail.m:43) 4 UIKit 0x386cb590 -[UIViewController loadViewIfRequired] + 360 5 UIKit 0x38757336 -[UIViewController shouldAutorotate] + 22 6 UIKit 0x38798cd4 -[UIWindowController transition:fromViewController:toViewController:target:didEndSelector:] + 1540 7 UIKit 0x38797fca -[UIViewController presentViewController:withTransition:completion:] + 3390 8 UIKit 0x388ba252 -[UIViewController presentModalViewController:animated:] + 26 9 Foundation 0x34364a6a __NSFireDelayedPerform + 446 10 CoreFoundation 0x379df5da __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 10 11 CoreFoundation 0x379df28c __CFRunLoopDoTimer + 268 12 CoreFoundation 0x379ddefc __CFRunLoopRun + 1228 13 CoreFoundation 0x37950eb8 0x37948000 + 36536 14 CoreFoundation 0x37950d44 CFRunLoopRunInMode + 100 15 GraphicsServices 0x373e32e6 GSEventRunModal + 70 16 UIKit 0x387002fc 0x386a9000 + 357116 17 OrientalDailyiOS 0x0005fac2 main (main.m:16) 18 OrientalDailyiOS 0x0005fa84 0x5e000 + 6788 However, I couldn't know where is error, I play around with my apps but show no error. I also tried iOS 6 with iPad, no problem. what apple feedback was We found that your app crashed on iPad running iOS 6, which is not in compliance with the App Store Review Guidelines. Your app crashed on both Wi-Fi and cellular networks when we: 1. Launch the app. 2. Tap any item on main page. 3. App crashes.

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  • C++ STL question related to insert iterators and overloaded operators

    - by rshepherd
    #include <list> #include <set> #include <iterator> #include <algorithm> using namespace std; class MyContainer { public: string value; MyContainer& operator=(const string& s) { this->value = s; return *this; } }; int main() { list<string> strings; strings.push_back("0"); strings.push_back("1"); strings.push_back("2"); set<MyContainer> containers; copy(strings.begin(), strings.end(), inserter(containers, containers.end())); } The preceeding code does not compile. In standard C++ fashion the error output is verbose and difficult to understand. The key part seems to be this... /usr/include/c++/4.4/bits/stl_algobase.h:313: error: no match for ‘operator=’ in ‘__result.std::insert_iterator::operator* [with _Container = std::set, std::allocator ]() = __first.std::_List_iterator::operator* [with _Tp = std::basic_string, std::allocator ]()’ ...which I interpet to mean that the assignment operator needed is not defined. I took a look at the source code for insert_iterator and noted that it has overloaded the assignment operator. The copy algorithm must uses the insert iterators overloaded assignment operator to do its work(?). I guess that because my input iterator is on a container of strings and my output iterator is on a container of MyContainers that the overloaded insert_iterator assignment operator can no longer work. This is my best guess, but I am probably wrong. So, why exactly does this not work and how can I accomplish what I am trying to do?

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  • Rails how to return a list of answers with a specific question_id

    - by mytwocentsisworthtwocents
    Let's say I have two Models, Answers and Questions (there are others, but irrelevant to the question). The models are as follows: Answer.rb class Answer < ActiveRecord::Base attr_accessible :description, :question_id has_one :question, :through => :user, :dependent => :destroy validates :description, :presence => true end Question.rb class Question < ActiveRecord::Base attr_accessible :budget, :description, :headline, :user_id, :updated_at, :created_at belongs_to :user has_many :answers validates :headline, :description, :user_id, :presence => true end I'd like to display on a page a list of all answers associated with a question, and only those questions. I got this far. I believe this variable finds all the questions in the database by the question_id (foreign key): @findanswers = Answer.all(params[:question_id]) And this one grabs the the id of the current question (this code will reside as an ERB on the page where the current question is located): @questionshow = Question.find(params[:id]) And now I'm stuck. How do I put the two together so that I list all the answers with the current question id?

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  • Help on MySQL table indexing when GROUP BY is used in a query

    - by Silver Light
    Thank you for your attention. There are two INNODB tables: Table authors id INT nickname VARCHAR(50) status ENUM('active', 'blocked') about TEXT Table books author_id INT title VARCHAR(150) I'm running a query against these tables, to get each author and a count of books he has: SELECT a. * , COUNT( b.id ) AS book_count FROM authors AS a, books AS b WHERE a.status != 'blocked' AND b.author_id = a.id GROUP BY a.id ORDER BY a.nickname This query is very slow (takes about 6 seconds to execute). I have an index on books.author_id and it works perfectly, but I do not know how to create an index on authors table, so that this query could use it. Here is how current EXPLAIN looks: id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE a ALL PRIMARY,id_status_nickname NULL NULL NULL 3305 Using where; Using temporary; Using filesort 1 SIMPLE b ref key_author_id key_author_id 5 a.id 2 Using where; Using index I've looked at MySQL manual on optimizing queries with group by, but could not figure out how I can apply it on my query. I'll appreciate any help and hints on this - what must be the index structure, so that MySQL could use it?

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  • Will C++0x support __stdcall or extern "C" capture-nothing lambdas?

    - by Daniel Trebbien
    Yesterday I was thinking about whether it would be possible to use the convenience of C++0x lambda functions to write callbacks for Windows API functions. For example, what if I wanted to use a lambda as an EnumChildProc with EnumChildWindows? Something like: EnumChildWindows(hTrayWnd, CALLBACK [](HWND hWnd, LPARAM lParam) { // ... return static_cast<BOOL>(TRUE); // continue enumerating }, reinterpret_cast<LPARAM>(&myData)); Another use would be to write extern "C" callbacks for C routines. E.g.: my_class *pRes = static_cast<my_class*>(bsearch(&key, myClassObjectsArr, myClassObjectsArr_size, sizeof(my_class), extern "C" [](const void *pV1, const void *pV2) { const my_class& o1 = *static_cast<const my_class*>(pV1); const my_class& o2 = *static_cast<const my_class*>(pV2); int res; // ... return res; })); Is this possible? I can understand that lambdas that capture variables will never be compatible with C, but it at least seems possible to me that capture-nothing lambdas can be compatible.

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  • Create 2nd tables and add data

    - by Tyler Matema
    I have this task from school, and I am confuse and lost on how I got to do this. So basically I have to create 2 tables to the database but I have to created from php. I have created the first table, but not the second one for some reason. And then, I have to populate first and second tables with 10 and 20 sample records respectively, populate, does it mean like adding more fake users? if so is it like the code shown below? *I got error on the populating second part as well Thank you so much for the help. <?php $host = "host"; $user = "me"; $pswd = "password"; $dbnm = "db"; $conn = @mysqli_connect($host, $user, $pswd, $dbnm); if (!$conn) die ("<p>Couldn't connect to the server!<p>"); $selectData = @mysqli_select_db ($conn, $dbnm); if(!$selectData) { die ("<p>Database Not Selected</p>"); } //1st table $sql = "CREATE TABLE IF NOT EXISTS `friends` ( `friend_id` INT NOT NULL auto_increment, `friend_email` VARCHAR(20) NOT NULL, `password` VARCHAR(20) NOT NULL, `profile_name` VARCHAR(30) NOT NULL, `date_started` DATE NOT NULL, `num_of_friends` INT unsigned, PRIMARY KEY (`friend_id`) )"; //2nd table $sqlMyfriends = "CREATE TABLE `myfriends` ( `friend_id1` INT NOT NULL, `friend_id2` INT NOT NULL, )"; $query_result1 = @mysqli_query($conn, $sql); $query_result2 = @mysqli_query($conn, $sqlMyfriends); //populating 1st table $sqlSt3="INSERT INTO friends (friend_id, friend_email, password, profile_name, date_started, num_of_friends) VALUES('NULL','[email protected]','123','abc','2012-10-25', 5)"; $queryResult3 = @mysqli_query($dbConnect,$sqlSt3) //populating 2nd table $sqlSt13="INSERT INTO myfriends VALUES(1,2)"; $queryResult13=@mysqli_query($dbConnect,$sqlSt13); mysqli_close($conn); ?>

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  • How to do something when AVQueuePlayer finishes the last playeritem

    - by user1634529
    I've got an AVQueuePlayer which I'm creating from an array of 4 AVPlayerItems, and it all plays fine. I want to do something when the last item in the queue finishes playing, I've looked a load of answers on here and this is the one that looks most promising for what I want: The best way to execute code AFTER a sound has finished playing In my button handler i have this code: static const NSString *ItemStatusContext; [thePlayerItemA addObserver:self forKeyPath:@"status" options:0 context:&ItemStatusContext]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playerItemDidReachEnd) name:AVPlayerItemDidPlayToEndTimeNotification object:thePlayerItemA]; theQueuePlayer = [AVQueuePlayer playerWithPlayerItem:thePlayerItemA]; [theQueuePlayer play]; and then I have a function to handle playerItemDidReachEnd: - (void)playerItemDidReachEnd:(NSNotification *)notification { // Do stuff here NSLog(@"IT REACHED THE END"); } But when I run this I get an Internal Inconsistency Exception: An -observeValueForKeyPath:ofObject:change:context: message was received but not handled. Key path: status Observed object: <AVPlayerItem: 0x735a130, asset = <AVURLAsset: 0x73559c0, URL = file://localhost/Users/mike/Library/Application%20Support/iPhone%20Simulator/5.0/Applications/A0DBEC13-2DA6-4887-B29D-B43A78E173B8/Phonics%2001.app/yes.mp3>> Change: { kind = 1; } What am I doing wrong?

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  • Temporarily disable vim plugin without relaunching

    - by simont
    I'm using c-support in Vim. One of it's features is the automatic comment expansion. When I'm pasting code into Vim from an external editor, the comments are expanded (which gives me double-comments and messes up the paste - see below for example). I'd like to be able to disable the plugin, paste, then re-enable it, without relaunching Vim. I'm not sure if this is possible. The SO questions here, here and here all describe methods to disable plugins, but they all require me to close Vim, mess with my .vimrc or similar, and relaunch; if I have to close Vim, I might as well cat file1 >> myfile; vim myfile, then shift the lines internally, which will be just as quick. Is it possible to disable a plugin while running vim without relaunching, preferably in a way which allows me to map a hot-key toggle-plugin (so re-sourcing ~/.vimrc is alright; that's mappable to a hotkey [I imagine, haven't tried it yet])? Messed up comments: /* * * Authors: * * A Name * * * * Copyright: * * A Name, 2012 * */ EDIT: It turns out you can :set paste, :set nopaste (which, to quote :help paste, will "avoid unexpected effects [while pasting]". (See the comments). However, I'm still curious whether you can disable/enable a plugin as per the original question, so I shall leave the question open.

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