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  • How to change rows in a table based on other table rows in mysql?

    - by understack
    I've a table which has 3 columns: id, a_id and b_id. Suppose rows are like this: 1, a1, b1 2, a1, b2 3, a1, b3 4, a2, b4 5, a2, b5 6, a2, b6 I want to convert it to 1, a1, b1 2, a1, b1 3, a1, b1 4, a2, b4 5, a2, b4 6, a2, b4 So I want to make all the b_id corresponding to a_id same, and equal to the one which is found first. How can I do this? For simplicity, I've removed other columns from table. So please ignore row duplication here.

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  • DataSet with many OR clauses

    - by Silvan
    Hello :) I've got a little problem with a query which I create in the Visual Studio Designer. I need a query with a lot of 'OR'-clauses for the same column. I found the operator 'IN', but I don't know how to use that in the Visual Studio Designer: Example IN: SELECT EmployeeID, FirstName, LastName, HireDate, City FROM Employees WHERE City IN ('Seattle', 'Tacoma', 'Redmond') I tried to do it in this way: SELECT [MachineryId], [ConstructionSiteId], [DateTime], [Latitude], [Longitude], [HoursCounter] FROM [PositionData] WHERE [MachineryID] IN @MachineryIDs But this doesn't work. Is there another way to handle a lot of OR clauses? Thank you very much for your help.

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  • Is there an existing algorithm for this notation translation/conversion?

    - by John
    A system has a notation that would require writing an expression like (A+B)*C as #MUL(#ADD(A,B),C). Is there already an algorithm to do this kind of notation conversion so users can enter in a more conventional way? In other words an algorithm to convert from infix - my notation. First issue is I don't know an exact name for my notation... it's similar to reverse-polish but not quite. Every operator is encoded as a function taking arguments.

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  • Problem with updating multiple rows which are in conflict with unique index

    - by GUZ
    I am using Microsoft SQL Server and I have a master-detail scenario where I need to store the order of details. So in the Detail table I have ID, MasterID, Position and some other columns. There is also a unique index on MasterID and Position. It works OK except one case: when I have some existing details and I change their order. For example when I change a detail on position 3 with a detail on position 2. When I save the detail on position 2 (which in the database has Position equal to 3) SQL Server protests, because the index uniqueness constraint. How to solve this problem in a reasonable way? Thank you in advance Lukasz Glaz

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  • Binning into timeslots - Is there a better way than using list comp?

    - by flyingcrab
    I have a dataset of events (tweets to be specific) that I am trying to bin / discretize. The following code seems to work fine so far (assuming 100 bins): HOUR = timedelta(hours=1) start = datetime.datetime(2009,01,01) z = [dt + x*HOUR for x in xrange(1, 100)] But then, I came across this fateful line at python docs 'This makes possible an idiom for clustering a data series into n-length groups using zip(*[iter(s)]*n)'. The zip idiom does indeed work - but I can't understand how (what is the * operator for instance?). How could I use to make my code prettier? I'm guessing this means I should make a generator / iterable for time that yields the time in graduations of an HOUR?

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  • VS 2008 linking error

    - by AvatarBlue
    I'm using Visual Studio 2008 C++ and working on a dll project. Debug compiled and linked perfectly but when I compile the release version, it shows this: VImgPtr.obj : error LNK2001: unresolved external symbol @__security_check_cookie@4 VLibraryPtr.obj : error LNK2001: unresolved external symbol "void __cdecl operator delete[](void *)" (??_V@YAXPAX@Z) D:\Source Code\VImgLib\Release-vc9u\VImgLib-vc9u.dll : fatal error LNK1120: 2 unresolved externals If I selected Multi-threaded (/MT) in "C/C++-Code Generation tab), it linked ok. The problem is only when I choose Multi-threaded DLL (/MD). I'm releasing a dll, so should be /MD right?

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  • I need to do a BASICE For Loop algorithm for a java Pyramid

    - by user1665119
    Question 2. USE THE FOR LOOP. Design and write an algorithm that will read a single positive number from the keyboard and will then print a pyramid out on the screen. The pyramid will need to be of a height equal in lines to the number inputted by the operator. Your program is not to test for negative numbers, nor is it to cater for them. For your test, use the number 7. If you would like to take the problem further, try 18 and watch what happens. Example input: 4 Example output: 1 121 12321 1234321

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  • How to center elements in the BoxLayout using center of the element?

    - by Roman
    I use outputPanel.setLayout(new BoxLayout(outputPanel, BoxLayout.Y_AXIS)); and then I add elements (for example JLabels, JButtons) to the outputPanel. For example: outputPanel.add(submitButton);. I see that all added elements are "centered". It is good, because I do want my elements to be in the center. When I write "center" I mean "equal distance from left and right". But the problem is that the left part of the element is put into the center. And I want to have center of elements to be put into the center. How can I get this behavior?

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  • error: typedef name may not be a nested-name-specifier

    - by Autopulated
    I am trying to do something along the lines of this answer, and struggling: $ gcc --version gcc (GCC) 4.2.4 (Ubuntu 4.2.4-1ubuntu4) file.cpp:7: error: template argument 1 is invalid file.cpp:7: error: typedef name may not be a nested-name-specifier And the offending part of the file: template <class R, class C, class T0=void, class T1=void, class T2=void> struct MemberWrap; template <class R, class C, class T0> struct MemberWrap<R, C, T0>{ typedef R (C::*member_t)(T0); typedef typename boost::add_reference<typename T0>::type> TC0; // <---- offending line MemberWrap(member_t f) : m_wrapped(f){ } R operator()(C* p, TC0 p0){ GILRelease guard; return (p->*(this->m_wrapped))(p0); } member_t m_wrapped; };

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  • functor returning 0

    - by Jon
    I've recently started teaching myself the standard template library. I was curious as to why the GetTotal() method in this class is returning 0? ... class Count { public: Count() : total(0){} void operator() (int val){ total += val;} int GetTotal() { return total;} private: int total; }; void main() { set<int> s; Count c; for(int i = 0; i < 10; i++) s.inset(i); for_each(s.begin(), s.end(), c); cout << c.GetTotal() << endl; }

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  • How to call a method withgin a vector?

    - by Mike Dooley
    Hi! How do I call a method of an object which is stored within a vector? The following code fails... ClassA* class_derived_a = new ClassDerivedA; ClassA* class_another_a = new ClassAnotherDerivedA; vector<ClassA*> test_vector; test_vector.push_back(class_derived_a); test_vector.push_back(class_another_a); for (vector<ClassA*>::iterator it = test_vector.begin(); it != test_vector.end(); it++) it->printOutput(); The code retrieves the following error: test3.cpp:47: error: request for member ‘printOutput’ in ‘* it.__gnu_cxx::__normal_iterator<_Iterator, _Container::operator- with _Iterator = ClassA**, _Container = std::vector ’, which is of non-class type ‘ClassA*’ The problem seems to be it->printOutput(); but at the moment I don't know how to call the method properly, does anyone know? regards mikey

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  • Multiset of shared_ptrs as a dynamic priority queue: Concept and practice

    - by Sarah
    I was using a vector-based priority queue typedef std::priority_queue< Event, vector< Event >, std::greater< Event > > EventPQ; to manage my Event objects. Now my simulation has to be able to find and delete certain Event objects not at the top of the queue. I'd like to know if my planned work-around can do what I need it to, and if I have the syntax right. I'd also like to know if dramatically better solutions exist. My plan is to make EventPQ a multiset of smart pointers to Event objects: typedef std::multi_set< boost::shared_ptr< Event > > EventPQ; I'm borrowing functions of the Event class from a related post on a multimap priority queue. // Event.h #include <cstdlib> using namespace std; #include <set> #include <boost/shared_ptr.hpp> class Event; typedef std::multi_set< boost::shared_ptr< Event > > EventPQ; class Event { public: Event( double t, int eid, int hid ); ~Event(); void add( EventPQ& q ); void remove(); 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; EventPQ* mq; EventPQ::iterator mIt; }; // Event.cpp Event::Event( double t, int eid, int hid ) { time = t; eventID = eid; hostID = hid; } Event::~Event() {} void Event::add( EventPQ& q ) { mq = &q; mIt = q.insert( boost::shared_ptr<Event>(this) ); } void Event::remove() { mq.erase( mIt ); mq = 0; mIt = EventPQ::iterator(); } I was hoping that by making EventPQ a container of pointers, I could avoid wasting time copying Events into the container and avoid accidentally editing the wrong copy. Would it be dramatically easier to store the Events themselves in EventPQ instead? Does it make more sense to remove the time keys from Event objects and use them instead as keys in a multimap? Assuming the current implementation seems okay, my questions are: Do I need to specify how to sort on the pointers, rather than the objects, or does the multiset automatically know to sort on the objects pointed to? If I have a shared_ptr ptr1 to an Event that also has a pointer in the EventPQ container, how do I find and delete the corresponding pointer in EventPQ? Is it enough to .find( ptr1 ), or do I instead have to find by the key (time)? Is the Event::remove() sufficient for removing the pointer in the EventPQ container? There's a small chance multiple events could be created with the same time (obviously implied in the use of multiset). If the find() works on event times, to avoid accidentally deleting the wrong event, I was planning to throw in a further check on eventID and hostID. Does this seem reasonable? (Dumb syntax question) In Event.h, is the declaration of dummy class Event;, then the EventPQ typedef, and then the real class Event declaration appropriate? I'm obviously an inexperienced programmer with very spotty background--this isn't for homework. Would love suggestions and explanations. Please let me know if any part of this is confusing. Thanks.

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  • TSQL, select values from large many-to-many relationship

    - by eugeneK
    I have two tables Publishers and Campaigns, both have similar many-to-many relationships with Countries,Regions,Languages and Categories. more info Publisher2Categories has publisherID and categoryID which are foreign keys to publisherID in Publishers and categoryID in Categories which are identity columns. On other side i have Campaigns2Categories with campaignID and categoryID columns which are foreign keys to campaignID in Campaigns and categoryID in Categories which again are identities. Same goes for Regions, Languages and Countries relationships I pass to query certain publisherID and want to get campaignIDs of Campaigns that have at least one equal to Publisher value from regions, countries, language or categories thanks

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  • How do I make a sql query where fields are the result of a different query?

    - by CRP
    I have two tables, the first is like this: f1 | f2 | f3 | f4 ----------------- data.... the second contains info about the fields of the first: field | info ------------ f1 a f2 b f3 a etc. I would like to query the first table selecting the fields with a query on the second. So, for example, I might want to get data for fields where info is equal to "a", thus I would do "select f1, f3 from first_table". How do I do this programmatically? I was thinking about something along the lines of select (select fields from second_table where info='a') from first_table Thanks Chris

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  • Side effects of reordering columns in PostgreSQL

    - by Summer
    I sometimes re-order the columns in my Postgres DB. Since Postgres can only add columns at the end of tables, I end up re-ordering by adding new columns at the end of the table, setting them equal to existing columns, and then dropping the original columns. My question is: what does PostgreSQL do with the memory that's freed by dropped columns? Does it automatically re-use the memory, so a single record consumes the same amount of space as it did beforehand? But that would require a re-write of the whole table, so to avoid that, does it just keep a bunch of blank space around in each record? Thanks! ~S

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  • dragging components in flex

    - by SuperString
    so I am trying to drag around some images in a canvas. I am adding eventlisteners to the components and calling startDrag() and stopDrag() to pick them up and stuff: component.addEventListener(MouseEvent.MOUSE_DOWN, component.startDrag) The problem is that it is selecting the image at its (0,0) location and not where I initially click on it. So there's a sudden "jump" when I click on the image. It is not smooth. I noticed that startDrag() has two default parameters, one of them is lockCenter and it is default to false. Maybe do I set it equal to true somehow? (I don't know how to pass arguments to my second parameter in addeventlistener) Another question: if I want to add more conditions to it, like make a new function that uses component.startDrag(), how do I pass the component to this function while adding event listener to it at the same time? for example: I want to do: component.addEventListener(MouseEvent.MOUSE_DOWN, some_other_function); where some_other_function uses component.startDrag(); Thanks!

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  • How to exclude results with get_object_or_404?

    - by googletorp
    In Django you can use the exclude to create SQL similar to not equal. An example could be. Model.objects.exclude(status='deleted') Now this works great and exclude is very flexible. Since I'm a bit lazy, I would like to get that functionality when using get_object_or_404, but I haven't found a way to do this, since you cannot use exclude on get_object_or_404. What I want is to do something like this: model = get_object_or_404(pk=id, status__exclude='deleted') But unfortunately this doesn't work as there isn't an exclude query filter or similar. The best I've come up with so far is doing something like this: object = get_object_or_404(pk=id) if object.status == 'deleted': return HttpResponseNotfound('text') Doing something like that, really defeats the point of using get_object_or_404, since it no longer is a handy one-liner. Alternatively I could do: object = get_object_or_404(pk=id, status__in=['list', 'of', 'items']) But that wouldn't be very maintainable, as I would need to keep the list up to date. I'm wondering if I'm missing some trick or feature in django to use get_object_or_404 to get the desired result?

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  • How Serializable works with insert in SQL Server 2005

    - by Spence
    G'day I think I have a misunderstanding of serializable. I have two tables (data, transaction) which I insert information into in a serializable transaction (either they are both in, or both out, but not in limbo). SET TRANSACTION ISOLATION LEVEL SERIALIZABLE BEGIN TRANSACTION INSERT INTO dbo.data (ID, data) VALUES (@Id, data) INSERT INTO dbo.transactions(ID, info) VALUES (@ID, @info) COMMIT TRANSACTION I have a reconcile query which checks the data table for entries where there is no transaction at read committed isolation level. INSERT INTO reconciles (ReconcileID, DataID) SELECT Reconcile = @ReconcileID, ID FROM Data WHERE NOT EXISTS (SELECT 1 FROM TRANSACTIONS WHERE data.id = transactions.id) Note that the ID is actually a composite (2 column) key, so I can't use a NOT IN operator My understanding was that the second query would exclude any values written into data without their transaction as this insert was happening at serializable and the read was occurring at read committed. I have evidence that reconcile is picking up entries

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  • How do I programmatically nullify a File Attachment in InfoPath Forms

    - by Doctor Zinda
    Howdy all, I'm running into a problem with some InfoPath C# code while trying to remove an attachment from a form. Basically the process is: User opens form User clicks button File attachment is cleared I've tried adding a blank attachment to my schema that never becomes populated, then setting the original field's value equal to that value by the method below. When debugging the form I catch an error: Schema validation found non-data type errors. Any tips here would be appreciated. public void BTN_ClearAttachment_Clicked(object sender, ClickedEventArgs e) { try { _OriginalAttachment.SetValue(_BLANK_ATTACHMENT.Value); } catch (Exception ex) { _ErrorField.SetValue(ex.Message + " : " + ex.StackTrace); } } Thanks, Dr Z Edit - P.S. I should clear up that both _OriginalAttachment & _ErrorField are both XPathNavigators, pointing at different schema elements. I've verified that these XPathNavigators are both pointing at valid schema elements.

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  • SQL only row mapping record fetching

    - by Prasanna
    I have a customer call detail table in which call details of all customer stored. I have to find out the distinct aparty (means our customer ) who only calls our customers (means bparty also be our numbers) . There is no other domestic call , International calls made by A party (our customer) in this case. could you people please help me to find the same data. FILE INPUT oF SAMPLE CDR TABLE ROW NAME VALUES ANUMBER :-any mobile number(Domestic+International); for our customer it must like 70,070,0070,9370) BNUMBER :-any mobile number(Domestic+International); for our customer it must like 70,070,0070,9370 CALLTRANSACTION :-eg: 91,92,93 etc CALLTRANSACTIONTYPEC :-eg: MOC,MTC FILENAME :-MCS_01 etc TIME:- any time value Required Output DISTINCT ANUMBER :-for our customer it mobile number must start with 70 or 070 or 0070 or 9370 BNUMBER :- for our customer it mobile number must start with 70 or 070 or 0070 or 9370 means our customer only calls to our network customer ( No other doestic call or international calls made by our operator)

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  • Creating ostream manipulators for a specific class

    - by petersohn
    I have a class that is derived from ostream: class my_ostream: public std::ostream { // ... } I want to make a manipulator (for example do_something), that works specifically to this class, like this: my_ostream s; s << "some text" << do_something << "some more text"; I did the following: std::ostream &do_something(std::ostream &os) { my_ostream *s = dynamic_cast<my_ostream*>(&os); if (s != NULL) { // do something } return os; } This works, but is rather ugly. I tried the following: my_ostream &do_something(my_ostream &s) { // do something return s; } This doesn't work. I also tried another approach: class my_ostream: public std::ostream { // ... my_ostream &operator<<(const do_something & x) { // do something return *this; } } This still doesn't work.

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  • How to use a object whose copy constructor and copy assignment is private?

    - by coanor
    In reading TCPL, I got a problem, as the title refered, and then 'private' class is: class Unique_handle { private: Unique_handle& operator=(const Unique_handle &rhs); Unique_handle(const Unique_handle &rhs); public: //... }; the using code is: struct Y { //... Unique_handle obj; }; and I want to execute such operations: int main() { Y y1; Y y2 = y1; } although, these code are come from TCPL, but I still can not got the solution... Can anybody help me, appreciate.

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  • Container for database-like searches

    - by Milan Babuškov
    I'm looking for some STL, boost, or similar container to use the same way indexes are used in databases to search for record using a query like this: select * from table1 where field1 starting with 'X'; or select * from table1 where field1 like 'X%'; I thought about using std::map, but I cannot because I need to search for fields that "start with" some text, and not those that are "equal to". I could create a sorted vector or list and use binary search (breaking the set in 2 in each step by reading the element in the middle and seeing if it's more or less than 'X'), but I wonder if there is some ready-made container I could use without reinventing the wheel?

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  • Dynamic allocated array is not freed

    - by Stefano
    I'm using the code above to dynamically allocate an array, do some work inside the function, return an element of the array and free the memory outside of the function. But when I try to deallocate the array it doesn't free the memory and I have a memory leak. The debugger pointed to the myArray variable shows me the error CXX0030. Why? struct MYSTRUCT { char *myvariable1; int myvariable2; char *myvariable2; .... }; void MyClass::MyFunction1() { MYSTRUCT *myArray= NULL; MYSTRUCT *myElement = this->MyFunction2(myArray); ... delete [] myArray; } MYSTRUCT* MyClass::MyFunction2(MYSTRUCT *array) { array = (MYSTRUCT*)operator new(bytesLength); ... return array[X]; }

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  • Puzzle related to cake [closed]

    - by Abhi
    Dear All While having tea with one of my colleague at evening time yesterday. He asked me one puzzle related to cake. The puzzle goes this way: Suppose i have a circular cake. And to that cake, I have to cut three times anywhere with maximum number of pieces without bothering abt the equal segment So how many maximum number of pieces it will make? A/c to me, the maximum number of pieces will be 7. But i am not sure. So please can u all tell me how many maximum number of pieces it will make & how? Please answer one at a time..... Thanks in advance...

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