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Search found 20401 results on 817 pages for 'null coalescing operator'.

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  • Oracle function always returning null

    - by JavaRocky
    I can't get this function to behave as i desire. Can anyone point out why it always returns null instead of CURRENT_TIMESTAMP? CREATE OR REPLACE FUNCTION nowts RETURN TIMESTAMP IS vTimestamp TIMESTAMP; BEGIN SELECT type_date INTO vTimestamp FROM param_table WHERE param_table = 3 AND exists ( SELECT * FROM param_table WHERE param_table = 2 ); IF vTimestamp IS NULL THEN vTimestamp := CURRENT_TIMESTAMP; END IF; return vTimestamp; END nowts; Right now there is nothing in the table named param_table.

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  • Tag property null when data binding

    - by rotary_engine
    Can anyone see what is wrong with this? The Tag property is returning null however the Binding for Id property is definately returning an int value. <ListBox ItemsSource="{Binding ElementName=myDomainDataSource, Path=Data}"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <TextBlock Text="{Binding Path=Id, Mode=OneWay}" /> <HyperlinkButton Content="Edit" Tag="{Binding ElementName=Id, Mode=OneWay}" Click="Edit_Click" /> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox> and then... private void Edit_Click(object sender, RoutedEventArgs e) { ContentControl c = sender as ContentControl; // exception - c.Tag is null int id = (int)c.Tag; } The Id property is showing a value on the UI, but doesn't seem to be getting stored in the buttons Tag property.

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  • Is there a shorthand way to denullify a string in C#?

    - by Moose Factory
    Is there a shorthand way to denullify a string in C#? It would be the equivalent of (if 'x' is a string): string y = x == null ? "" : x; I guess I'm hoping there's some operator that would work something like: string y = #x; Wishful thinking, huh? The closest I've got so far is an extension method on the string class: public static string ToNotNull(this string value) { return value == null ? "" : value; } which allows me to do: string y = x.ToNotNull(); Any improvements on that, anyone?

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  • Quick, Beginner C++ Overloading Question - Getting the compiler to perceive << is defined for a spec

    - by Francisco P.
    Hello everyone. I edited a post of mine so I coul I overloaded << for a class, Score (defined in score.h), in score.cpp. ostream& operator<< (ostream & os, const Score & right) { os << right.getPoints() << " " << right.scoreGetName(); return os; } (getPoints fetches an int attribute, getName a string one) I get this compiling error for a test in main(), contained in main.cpp binary '<<' : no operator found which takes a right-hand operand of type 'Score' (or there is no acceptable conversion) How come the compiler doesn't 'recognize' that overload as valid? (includes are proper) Thanks for your time.

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  • getResourceAsStream() is always returning null

    - by Andreas Grech
    I have the following structure in a Java Web Application: TheProject -- [Web Pages] -- -- [WEB-INF] -- -- -- abc.txt -- -- index.jsp -- [Source Packages] -- -- [wservices] -- -- -- WS.java In WS.java, I am using the following code in a Web Method: InputStream fstream = this.getClass().getResourceAsStream("abc.txt"); But it is always returning a null. I need to read from that file, and I read that if you put the files in WEB-INF, you can access them with getResourceAsStream, yet the method is always returning a null. Any ideas of what I may be doing wrong? Btw, the strange thing is that this was working, but after I performed a Clean and Build on the Project, it suddenly stopped working :/

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  • .save puts NULL in user_id field in Ruby on Rails

    - by mathee
    Here's the model file: class ProfileTag < ActiveRecord::Base def self.create_or_update(options = {}) id = options.delete(:id) record = find_by_id(id) || new record.id = id record.attributes = options puts "record.profile_id is" puts record.profile_id record.save! record end end This gives me the correct print out in my log. But it also says that there's a call to UPDATE that sets profile_id to NULL. I'm not sure I understand why the INSERT puts the value into profile_id properly, but then it sets it to NULL on an UPDATE. If you need more specifics, please let me know. I'm thinking that the save functionality does many things other than INSERTs into the database, but I don't know what I need to specify so that it will properly set profile_id.

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  • How to have NHibernate persist a String.Empty property value as NULL

    - by Todd
    I have a fairly simple class that I want to save to SQL Server via NHibernate (w/ Fluent mappings). The class is made up mostly of optional string fields. My problem is I default the class fields to string.empty to avoid NullRefExceptions and when NHibernate saves the row to the database each column contains an empty string instead of null. Question: Is there a way for me to get NHibernate to automatically save null when the string property is an empty string? Or do I need to litter my code with if (string.empty) checks?

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  • Why is address zero used for null pointer?

    - by Joel
    In C (or C++ for that matter), pointers are special if they have the value zero: I am adviced to set pointers to zero after freeing their memory, because it means freeing the pointer again isn't dangerous; when I call malloc it returns a pointer with the value zero if it can't get me memory; I use if (p != 0) all the time to make sure passed pointers are valid etc. But since memory addressing starts at 0, isn't 0 just as a valid address as any other? How can 0 be used for handling null pointers if that is the case? Why isn't a negative number null instead?

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  • UIWebView appears null when calling fro a method

    - by Alexidze
    I have a major problem when trying to access a UIWebView that was created during ViewDidLoad, the UIWebView appears null here is how i declare the property @property (nonatomic, retain) UIWebView *detailsView; the implementation @implementation iPadMainViewController @synthesize detailsView; - (void)viewDidLoad { [super viewDidLoad]; detailsView = [[UIWebView alloc] initWithFrame:CGRectMake(500, 0, 512, 768)]; [self.view addSubView:detailsView]; } When accessing from - (void)loadDetailedContent:(NSString *)s { NSLog(@"%@", detailsView); } I get NULL, is it a normal behavior or am i doing something wrong? here is the touchesBegan that is being called, from the views subclass that is being touched, -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { iPadMainViewController *mycontroller = [[iPadMainViewController alloc] init]; self.delegate = mycontroller; [self.delegate loadDetailedContent:NewsId]; }

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  • Oracle: Finding Columns with only null values

    - by Jorge Valois
    I have a table with a lot of columns and a type column. Some columns seem to be always empty for a specific type. I want to create a view for each type and only show the relevant columns for each type. Working under the assumption that if a column has ONLY null values for a specific type, then that columns should not be part of the view, how can you find that out with queries? Is there a SELECT [columnName] FROM [table] WHERE [columnValues] ARE ALL [null] I know I COMPLETELY made it all up above... I'm just trying to get the idea across. Thanks in advance!

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  • Fragment savedInstanceState is always null (Android support lib)

    - by Evgeny Egorov
    I wrote a simple test project, but I cant understand why I always receive savedInstanceState = null in lifecycle methods onCreate, onCreateView and onActivityCreated. I change the screen orientation, see the log, but state not saved. Tell me please where is my mistake. Thanks. The code of fragment class is: public class TestFragment extends Fragment { private String state = "1"; @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { if (savedInstanceState != null) { //never works state = savedInstanceState.getString("state"); } //always prints 1 Toast.makeText(getActivity(), state, Toast.LENGTH_SHORT).show(); return inflater.inflate(R.layout.fragment_layout, container, false); } @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); outState.putString("state", "2"); Log.e("", "saved 2"); } }

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  • BitmapFactory.decodeResource returns null value

    - by krasnoff
    I am tring to load bitmaps from an internal resource in a View object (the source itself is in "drawable" files). the code is: import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.util.AttributeSet; import android.view.View; public class BannerView extends View { private Bitmap m_Banner = null; public BannerView(Context context, AttributeSet attributeSet) { super(context, attributeSet); m_Banner = BitmapFactory.decodeResource(getResources(), R.drawable.banner); } } Why m_Banner value is null? thank you in advance Kobi

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  • Which is the better way to simulate optional parameters in Java?

    - by froadie
    I have a Java method that takes 3 parameters, and I'd like it to also have a 4th "optional" parameter. I know that Java doesn't support optional parameters directly, so I coded in a 4th parameter and when I don't want to pass it I pass null. (And then the method checks for null before using it.) I know this is kind of clunky... but the other way is to overload the method which will result in quite a bit of duplication. Which is the better way to implement optional method parameters in Java: using a nullable parameter, or overloading? And why?

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  • Drupal - db_fetch_array returns NULL for every row

    - by darudude
    I'm using Drupal's db_fetch_array to fetch rows from my db_query. However, every row returned is equal to NULL. Typing the query into PHP myadmin works, so I have no idea whats going on. db_num_rows returns the number of rows as well. Here is the code: if(count($rebuild_ids)) { $ids=implode(",",$rebuild_ids); $type_stmt = "SELECT * from {" . ItemType::$type_table_name . "} where id IN ($ids)"; $new_items=db_query($type_stmt); if(!$new_items || db_num_rows($new_items) == 0) { return; } while($row = db_fetch_array($new_items)); { if ($row!=NULL) { echo "I work!" $game_items[] = $row['id']; ItemInstance::$nid_to_item_type_code[$row['nid']] = $row['id']; } } } However, it never gets into the third if statement (i.e. never echos "I work!") Any ideas?

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  • Acceptable name for extension method that accept null

    - by GaryX
    Hi, I really don't like to call String.IsNullOrEmpty(str). That makes me need to think "String" class first, then call it on the object "str". I like to call str.IsNullOrEmpty(), which doesn't need me to think "String" class. The problem is that extension method accept null instance to call on, which is not the usual case when you call a normal method. My question what do you think will be a convetion name for extension methods that accept null? For string, that is easy, "IsNullOrEmpty()" (anything that contains "IsNull") sounds good for me. For others, like GetDisplayName(), do we name it as "NullOrGetDisplayName" ?

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  • Checking sqlite datetime NULL with RoR

    - by Paul N
    RoR/SQL newbie here. My datetime column 'deleted_at' are all uninitialized. Running this query returns an error: SELECT * FROM variants v ON v.id = ovv0.variant_id INNER JOIN option_values_variants ovv1 ON v.id = ovv1.variant_id INNER JOIN option_values_variants ovv2 ON v.id = ovv2.variant_id INNER JOIN option_values_variants ovv3 ON v.id = ovv3.variant_id INNER JOIN option_values_variants ovv4 ON v.id = ovv4.variant_id WHERE v.deleted_at = NULL AND v.product_id = 1060500595 However, if I set my datetime values to 0, and set my query to v.deleted_at = 0, the correct variant is returned to me. How do I check for uninitialized/NULL datetimes?

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  • PHP radio button check if null

    - by Dallox
    So in class we get this school task where we need to check if one of the fields in unfilled and display an error. No we did this but for some strange reason it doesnt display a error when a radio button is unchecked. (textfield null check works fine) I've tried with a friend many possabilities but they all doesnt seem to work. We have been stuck at this task for 2 hours. Now we have tried making seperate if's but that doesnt seem to work too. These are the important parts: <p> <input type="hidden" name="taal" value="false"> Choose a language <input type="radio" name="taal" value="N"> Dutch <input type="radio" name="taal" value="E"> English <input type="radio" name="taal" value="S"> Spanish if (@$_POST['taal'] == null){ echo "No Language gotten"; return; }

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  • Using "as" and expecting a null return

    - by DrLazer
    For example. Lets say we have a stackpanel on a form. Its full of both Grids and Labels. I want to loop through all the Grids and do some operation on them but leave the Lables intact. At the moment I am doing it this way. foreach(UIElement element in m_stacker.Children) { Grid block = element as Grid; if(block != null) { //apply changes here } } So i'm using the fact that "as" returns null if it cannot cast into the required type. Is this an ok thing to do or is there a better solution to this problem?

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  • returning null or throwing an exception?

    - by MoKi
    I have the following types: typedef QPair < QTime , QTime > CalculatedTimeSlotRange; typedef QList < CalculatedTimeSlotRange > CalculatedTimeSlotRangeList; typedef QHash < quint8 , CalculatedTimeSlotRangeList > TimeSlotsTable; I have a function like the following: const CalculatedTimeSlotRangeList* TimeSlots::getCalculatedTimeSlotRangeList(const quint8 id) const { QHashIterator<quint8,CalculatedTimeSlotRangeList> it(mTimeSlotsTable); while (it.hasNext()) { it.next(); if(it.key() == id) { return &it.value(); } } return NULL; } as you can see my function returns a null if it fails to find a key that matches id. Is this correct? or should I just throw an exception if the key does not exist? how should i throw an exception for this situation?

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  • Why is this C++ code working ?

    - by gregseth
    Why doesn't the program segfault on the p->info() call? struct A { int info() { retrun (this) ? 1 : -1; } }; int main() { A* p = NULL; if (p->info() == 1) { cout << "I'm alive!" << endl; } else { cout << "I'm NULL..." << endl; } return 0; }

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  • null pointer exception in textview of setcontent

    - by kitokid
    I am getting the java.lang.NullPointerException on createTabContent for the following code. There are two tabspecs. When I called and set the tab , changed the tabs for the first time it is ok. But when i called again while I am on the second tab, its hit the null pointer exception for line : NoStudentText.setVisibility(View.VISIBLE); I will show No Student Text if there is no data for the student list. It shows the text for the first time call. But If I do second time call to that tab, got the error. tspecStudent.setContent(new TabContentFactory() { public View createTabContent(String arg0) { if(listStudent != null && listStudent .size() > 0) { //show the student list } else { TextView noStudentText = (TextView)findViewById(R.id.NoStudentText); noStudentText.setVisibility(View.VISIBLE); return noStudentText; } } });

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  • C++: How to make comparison function for char arrays?

    - by Newbie
    Is this possible? i get weird error message when i put char as the type: inline bool operator==(const char *str1, const char *str2){ // ... } Error message: error C2803: 'operator ==' must have at least one formal parameter of class type ... which i dont understand at all. I was thinking if i could directly compare stuff like: const char *str1 = "something"; const char *str2 = "something else"; const char str3[] = "lol"; // not sure if this is same as above and then compare: if(str1 == str2){ // ... } etc. But i also want it to work with: char *str = new char[100]; and: char *str = (char *)malloc(100); I am assuming every char array i use this way would end in NULL character, so the checking should be possible, but i understand it can be unsafe etc. I just want to know if this is possible to do, and how.

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  • question regarding "this" pointer in c++

    - by sil3nt
    hello there, i have been given class with int variables x and y in private, and an operator overload function, class Bag{ private: int x; int y; public: Bag(); ~Bag(); //....... //.....etc }; Bag operator+ (Bag new) const{ Bag result(*this); //what does this mean? result.x += new.x; result.y += new.y; } What is the effect of having "Bag result(*this);" there?.

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