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  • MySQL Removing Some Foreign keys

    - by Drew
    I have a table whose primary key is used in several other tables and has several foreign keys to other tables. CREATE TABLE location ( locationID INT NOT NULL AUTO_INCREMENT PRIMARY KEY ... ) ENGINE = InnoDB; CREATE TABLE assignment ( assignmentID INT NOT NULL AUTO_INCREMENT PRIMARY KEY, locationID INT NOT NULL, FOREIGN KEY locationIDX (locationID) REFERENCES location (locationID) ... ) ENGINE = InnoDB; CREATE TABLE assignmentStuff ( ... assignmentID INT NOT NULL, FOREIGN KEY assignmentIDX (assignmentID) REFERENCES assignment (assignmentID) ) ENGINE = InnoDB; The problem is that when I'm trying to drop one of the foreign key columns (ie locationIDX) it gives me an "ERROR 1025 (HY000): Error on rename" error. How can I drop the column in the assignment table above without getting this error?

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  • new >> how would i read a file that has 3 columns and each column contains 100 numbers into an array

    - by user320950
    int exam1[100];// array that can hold 100 numbers for 1st column int exam2[100];// array that can hold 100 numbers for 2nd column int exam3[100];// array that can hold 100 numbers for 3rd column void main() { ifstream infile; int num; infile.open("example.txt");// file containing numbers in 3 columns if(infile.fail()) // checks to see if file opended { cout << "error" << endl; } while(!infile.eof()) // reads file to end of line { for(i=0;i<100;i++); // array numbers less than 100 { while(infile >> [exam]); // while reading get 1st array or element ???// how will i go read the next number infile >> num; } } infile.close(); }

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  • How to treat Base* pointer as Derived<T>* pointer?

    - by dehmann
    I would like to store pointers to a Base class in a vector, but then use them as function arguments where they act as a specific class, see here: #include <iostream> #include <vector> class Base {}; template<class T> class Derived : public Base {}; void Foo(Derived<int>* d) { std::cerr << "Processing int" << std::endl; } void Foo(Derived<double>* d) { std::cerr << "Processing double" << std::endl; } int main() { std::vector<Base*> vec; vec.push_back(new Derived<int>()); vec.push_back(new Derived<double>()); Foo(vec[0]); Foo(vec[1]); delete vec[0]; delete vec[1]; return 0; } This doesn't compile: error: call of overloaded 'Foo(Base*&)' is ambiguous Is it possible to make it work? I need to process the elements of the vector differently, according to their int, double, etc. types.

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  • Resultset (getter/setter class) object not deleting old values at 2nd Time execution in swin

    - by user2384525
    I have summarizeData() method and called so many time for value retrieve. but first time is working file but 2nd time execution value is increasing in HashMap. void summarizeData() { HashMap outerMap = new HashMap(); ArrayList list = new ArrayList(dataClass.getData()); for (int indx = 0; indx < list.size(); indx++) { System.out.println("indx : " + indx); Resultset rs = new Resultset(); rs = (Resultset) list.get(indx); if (rs != null) { int id = rs.getTestCaseNumber(); if (id > 0) { Object isExists = outerMap.get(id); if (isExists != null) { //System.out.println("found entry so updating"); Resultset inRs = new Resultset(); inRs = (Resultset) isExists; if (inRs != null) { int totExec = inRs.getTestExecution(); int totPass = inRs.getTestCasePass(); int totFail = inRs.getTestCaseFail(); // System.out.println("totE :" + totExec + " totP:" + totPass + " totF:" + totFail); int newRsStat = rs.getTestCasePass(); if (newRsStat == 1) { totPass++; inRs.setTestCasePass(totPass); } else { totFail++; inRs.setTestCaseFail(totFail); } totExec++; // System.out.println("id : "+id+" totPass: "+totPass+" totFail:"+totFail); // System.out.println("key : " + id + " val : " + inRs.getTestCaseNumber() + " " + inRs.getTestCasePass() + " " + inRs.getTestCaseFail()); inRs.setTestExecution(totExec); outerMap.put(id, inRs); } } else { // System.out.println("not exist so new entry" + " totE:" + rs.getTestExecution() + " totP:" + rs.getTestCasePass() + " totF:" + rs.getTestCaseFail()); outerMap.put(id, rs); } } } else { System.out.println("rs null"); } } Output at 1st Execution: indx : 0 indx : 1 indx : 2 indx : 3 indx : 4 indx : 5 indx : 6 indx : 7 indx : 8 indx : 9 indx : 10 totE :1 totP:1 totF:0 indx : 11 totE :1 totP:1 totF:0 indx : 12 totE :1 totP:1 totF:0 indx : 13 totE :1 totP:1 totF:0 indx : 14 totE :1 totP:1 totF:0 indx : 15 totE :1 totP:1 totF:0 indx : 16 totE :1 totP:1 totF:0 indx : 17 totE :1 totP:1 totF:0 indx : 18 totE :1 totP:1 totF:0 indx : 19 totE :1 totP:1 totF:0 Output at 2nd Execution: indx : 0 indx : 1 indx : 2 indx : 3 indx : 4 indx : 5 indx : 6 indx : 7 indx : 8 indx : 9 indx : 10 totE :2 totP:2 totF:0 indx : 11 totE :2 totP:2 totF:0 indx : 12 totE :2 totP:2 totF:0 indx : 13 totE :2 totP:2 totF:0 indx : 14 totE :2 totP:2 totF:0 indx : 15 totE :2 totP:2 totF:0 indx : 16 totE :2 totP:2 totF:0 indx : 17 totE :2 totP:2 totF:0 indx : 18 totE :2 totP:2 totF:0 indx : 19 totE :2 totP:2 totF:0 while i required same output on every execution.

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  • How can I get an NPC to move randomly in XNA?

    - by Fishwaffles
    I basically want a character to walk in one direction for a while, stop, then go in another random direction. Right now my sprites look but don't move, randomly very quickly in all directions then wait and have another seizure. I will post the code I have so far in case that is useful. class NPC: Mover { int movementTimer = 0; public override Vector2 direction { get { Random rand = new Random(); int randDirection = rand.Next(8); Vector2 inputDirection = Vector2.Zero; if (movementTimer >= 50) { if (randDirection == 4) { inputDirection.X -= 1; movingLeft = true; } else movingLeft = false; if (randDirection == 1) { inputDirection.X += 1; movingRight = true; } else movingRight = false; if (randDirection == 2) { inputDirection.Y -= 1; movingUp = true; } else movingUp = false; if (randDirection == 3) { inputDirection.Y += 25; movingDown = true; } else movingDown = false; if (movementTimer >= 100) { movementTimer = 0; } } return inputDirection * speed; } } public NPC(Texture2D textureImage, Vector2 position, Point frameSize, int collisionOffset, Point currentFrame, Point sheetSize, Vector2 speed) : base(textureImage, position, frameSize, collisionOffset, currentFrame, sheetSize, speed) { } public NPC(Texture2D textureImage, Vector2 position, Point frameSize, int collisionOffset, Point currentFrame, Point sheetSize, Vector2 speed, int millisecondsPerframe) : base(textureImage, position, frameSize, collisionOffset, currentFrame, sheetSize, speed, millisecondsPerframe) { } public override void Update(GameTime gameTime, Rectangle clientBounds) { movementTimer++; position += direction; if (position.X < 0) position.X = 0; if (position.Y < 0) position.Y = 0; if (position.X > clientBounds.Width - frameSize.X) position.X = clientBounds.Width - frameSize.X; if (position.Y > clientBounds.Height - frameSize.Y) position.Y = clientBounds.Height - frameSize.Y; base.Update(gameTime, clientBounds); } }

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  • typedef declaration syntax

    - by mt_serg
    Some days ago I looked at boost sources and found interesting typedef. There is a code from "boost\detail\none_t.hpp": namespace boost { namespace detail { struct none_helper{}; typedef int none_helper::*none_t ; } // namespace detail } // namespace boost I didn't see syntax like that earlier and can't explain the sense of that. This typedef introduces name "none_t" as pointer to int in boost::detail namespace. What the syntax is? And what difference between "typedef int none_helper::*none_t" and for example "typedef int *none_t" ?

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  • Database Structure for CakePHP Models

    - by Michael T. Smith
    We're building a data tracking web app using CakePHP, and I'm having some issues getting the database structure right. We have Companies that haveMany Sites. Sites haveMany DataSamples. Tags haveAndBelongToMany Sites. That is all set up fine. The problem is "ranking" the sites within tags. We need to store it in the database as an archive. I created a Rank model that is setup like this: rank ( id (int), sample_id (int), tag_id (int), site_id (int), rank (int), total_rows) ) So, the question is, how do I create the associations for tag, site and sample to rank? I originally set them as haveMany. But the returned structures don't get me where I'd like to be. It looks like: [Site] => Array ( [Sample] = Array(), [Tag] = Array() ) When I'm really looking for: [Site] => Array ( [Tag] = Array ( [Sample] => Array ( [Rank] => Array ( ...data... ) ) ) ) I think that I may not be structuring the database properly; so if I need to update please let me know. Otherwise, how do I write a find query that gets me where I need to be? Thanks! Thoughts? Need more details? Just ask!

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  • c++/cli pass (managed) delegate to unmanaged code

    - by Ron Klein
    How do I pass a function pointer from managed C++ (C++/CLI) to an unmanaged method? I read a few articles, like this one from MSDN, but it describes two different assemblies, while I want only one. Here is my code: 1) Header (MyInterop.ManagedCppLib.h): #pragma once using namespace System; namespace MyInterop { namespace ManagedCppLib { public ref class MyManagedClass { public: void DoSomething(); }; }} 2) CPP Code (MyInterop.ManagedCppLib.cpp) #include "stdafx.h" #include "MyInterop.ManagedCppLib.h" #pragma unmanaged void UnmanagedMethod(int a, int b, void (*sum)(const int)) { int result = a + b; sum(result); } #pragma managed void MyInterop::ManagedCppLib::MyManagedClass::DoSomething() { System::Console::WriteLine("hello from managed C++"); UnmanagedMethod(3, 7, /* ANY IDEA??? */); } I tried creating my managed delegate and then I tried to use Marshal::GetFunctionPointerForDelegate method, but I couldn't compile.

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  • An error saying unidentifed function "push", "pop", and"display" occurs, what should i add to fix i

    - by Alesha Aris
    #include<stdio.h> #include<iostream.h> #include<conio.h> #include<stdlib.h>(TOP) #include<fstream.h> #define MAX 5 int top = -1; int stack_arr[MAX]; main() { int choice; while(1) { printf("1.Push\n"); printf("2.Pop\n"); printf("3.Display\n"); printf("4.Quit\n"); printf("Enter your choice : "); scanf("%d",&choice); switch(choice) { case 1 : push(); break; case 2: pop(); break; case 3: display(); break; case 4: exit(1); default: printf("Wrong choice\n"); }/*End of switch*/ }/*End of while*/ }/*End of main()*/ push() { int pushed_item; if(top == (MAX-1)) printf("Stack Overflow\n"); else { printf("Enter the item to be pushed in stack : "); scanf("%d",&pushed_item); top=top+1; stack_arr[top] = pushed_item; } }/*End of push()*/ pop() { if(top == -1) printf("Stack Underflow\n"); else { printf("Popped element is : %d\n",stack_arr[top]); top=top-1; } }/*End of pop()*/ display() { int i; if(top == -1) printf("Stack is empty\n"); else { printf("Stack elements :\n"); for(i = top; i >=0; i--) printf("%d\n", stack_arr[i] ); } }/*End of display()*/

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  • Determining if a coordinate is on a line

    - by TGCBraun
    I´m coding a little app that allows the user to draw multiple shapes and then remove or resize them. It´s working perfectly on rectangles and ovals, but I´m having issues with lines. Here´s a method that I wrote to find if the clicked spot on the screen is part of a specific line: public boolean containsLocation(int x, int y) { int m = (getY2() - getY()) / (getX2() - getX()); int b = getY() - (m * getX()); if (y == (m * x) + b) { return true; } return false; I´m using the famous y = mx + b formula and replacing y and x to find if the clicked spot is part of the line. The problem is when I click on the screen to remove the line, it only works if I click on the very fist coordinate (x,y) where the line starts. Nothing happens when I click anywhere else along the line. Can anyone shed a light on what I´m doing wrong? Thanks a lot.

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  • Stored Procedure Parameters Not Available After Declared

    - by SidC
    Hi All, Pasted below is a stored procedure written in SQL Server 2005. My intent is to call this sproc from my ASP.NEt web application through the use of a wizard control. I am new to SQL Server and especially to stored procedures. I'm unsure why my parameters are not available to the web application and not visible in SSMS treeview as a parameter under my sproc name. Can you help me correct the sproc below so that the parameters are correctly instantiated and available for use in my web application? Thanks, Sid Stored Procedure syntax: USE [Diel_inventory] GO /****** Object: StoredProcedure [dbo].[AddQuote] Script Date: 05/09/2010 00:31:10 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO ALTER procedure [dbo].[AddQuote] as Declare @CustID int, @CompanyName nvarchar(50), @Address nvarchar(50), @City nvarchar(50), @State nvarchar(2), @ZipCode nvarchar(5), @Phone nvarchar(12), @FAX nvarchar(12), @Email nvarchar(50), @ContactName nvarchar(50), @QuoteID int, @QuoteDate datetime, @NeedbyDate datetime, @QuoteAmt decimal, @ID int, @QuoteDetailPartID int, @PartNumber float, @Quantity int begin Insert into dbo.Customers (CompanyName, Address, City, State, ZipCode, OfficePhone, OfficeFAX, Email, PrimaryContactName) Values (@CompanyName, @Address, @City, @State, @ZipCode, @Phone, @FAX, @Email, @ContactName) set @CustID = scope_identity() Insert into dbo.Quotes (fkCustomerID,NeedbyDate,QuoteAmt) Values(@CustID,@NeedbyDate,@QuoteAmt) set @QuoteID = scope_identity() Insert into dbo.QuoteDetail (ID) values(@ID) set @ID=scope_identity() Insert into dbo.QuoteDetailParts (QuoteDetailPartID, QuoteDetailID, PartNumber, Quantity) values (@ID, @QuoteDetailPartID, @PartNumber, @Quantity) END

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  • Drag N Drop utilizing simple cursor

    - by Cameron
    I'm using CommonsGuy's drag n drop example and I am basically trying to integrate it with the Android notepad example. Drag N Drop Out of the 2 different drag n drop examples i've seen they have all used a static string array where as i'm getting a list from a database and using simple cursor adapter. So my question is how to get the results from simple cursor adapter into a string array, but still have it return the row id when the list item is clicked so I can pass it to the new activity that edits the note. Here is my code: Cursor notesCursor = mDbHelper.fetchAllNotes(); startManagingCursor(notesCursor); // Create an array to specify the fields we want to display in the list (only NAME) String[] from = new String[]{WeightsDatabase.KEY_NAME}; // and an array of the fields we want to bind those fields to (in this case just text1) int[] to = new int[]{R.id.weightrows}; // Now create a simple cursor adapter and set it to display SimpleCursorAdapter notes = new SimpleCursorAdapter(this, R.layout.weights_row, notesCursor, from, to); setListAdapter(notes); And here is the code i'm trying to work that into. public class TouchListViewDemo extends ListActivity { private static String[] items={"lorem", "ipsum", "dolor", "sit", "amet", "consectetuer", "adipiscing", "elit", "morbi", "vel", "ligula", "vitae", "arcu", "aliquet", "mollis", "etiam", "vel", "erat", "placerat", "ante", "porttitor", "sodales", "pellentesque", "augue", "purus"}; private IconicAdapter adapter=null; private ArrayList<String> array=new ArrayList<String>(Arrays.asList(items)); @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); setContentView(R.layout.main); adapter=new IconicAdapter(); setListAdapter(adapter); TouchListView tlv=(TouchListView)getListView(); tlv.setDropListener(onDrop); tlv.setRemoveListener(onRemove); } private TouchListView.DropListener onDrop=new TouchListView.DropListener() { @Override public void drop(int from, int to) { String item=adapter.getItem(from); adapter.remove(item); adapter.insert(item, to); } }; private TouchListView.RemoveListener onRemove=new TouchListView.RemoveListener() { @Override public void remove(int which) { adapter.remove(adapter.getItem(which)); } }; class IconicAdapter extends ArrayAdapter<String> { IconicAdapter() { super(TouchListViewDemo.this, R.layout.row2, array); } public View getView(int position, View convertView, ViewGroup parent) { View row=convertView; if (row==null) { LayoutInflater inflater=getLayoutInflater(); row=inflater.inflate(R.layout.row2, parent, false); } TextView label=(TextView)row.findViewById(R.id.label); label.setText(array.get(position)); return(row); } } } I know i'm asking for a lot, but a point in the right direction would help quite a bit! Thanks

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  • how to call the method in thread with aruguments and return some value

    - by ratty
    i like to call the method in thread with aruguments and return some value here example class Program { static void Main() { Stopwatch stop = new Stopwatch(); stop.Start(); Thread FirstThread = new Thread(new ThreadStart(Fun1)); Thread SecondThread = new Thread(new ThreadStart(Fun2)); FirstThread.Start(); SecondThread.Start(); } public static void Fun1() { for (int i = 1; i <= 1000; i++) { Console.WriteLine("Fun1 writes:{0}", i); } } public static void Fun2() { for (int i = 1000; i >= 6; i--) { Console.WriteLine("Fun2 writes:{0}", i); } } } i know this above example run successfully but if method fun1 like this public int fun1(int i) { for (int n = i; n >= i+10; n++) { Console.WriteLine("Fun2 writes:{0}", i); } } then how can i call this in thread. Is it possible .Any body Help for me

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  • Showing an image after loading it from sql database

    - by user330075
    I have a problem showing the image form database in a view Details and a ImageController. Inside the view I have: img src=Url.Action("GetFile","Image", new {id= Model.id}) and in controller: public FileContentResult GetFile(int idl) { //int idl = 32; SqlDataReader rdr; byte[] fileContent = null; ........... return File(,,); } When the view is called, function GetFile it just won't work. But if I cut out the parameter int id1 and I instantiate it as a variable it does work. public FileContentResult GetFile() { int idl = 32; SqlDataReader rdr; byte[] fileContent = null; ........... return File(,,); } Why?

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  • C++: retrieve map values and insert into second map

    - by donalmg
    Hi, I have one map within one header file class: class One { // code typedef map<string, int> MapStrToInt inline MapStrToInt& GetDetails(unsigned long index) { return pData[index]; } // populate pData.... private: MapStrToInt *pData; }; And a second class which implements another map and wants to get the first 10 details from the class One's map. class Two { // code One::MapStrToInt pDataTen; int function1() { for (int i =0; i < 10; i ++) { One::MapStrToInt * pMap = &(One::GetDetails(i)); pDataTen.insert(pair<string, int>(pMap->first,pMap->second)); } } When I compile this, it states that pMap: has no member named 'first' has no member named 'second' Any suggestions? Thanks..

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  • Optional parameters for interfaces

    - by bryanjonker
    Using c# 4.0 -- building an interface and a class that implements the interface. I want to declare an optional parameter in the interface and have it be reflected in the class. So, I have the following: public interface IFoo { void Bar(int i, int j=0); } public class Foo { void Bar(int i, int j=0) { // do stuff } } This compiles, but it doesn't look right. The interface needs to have the optional parameters, because otherwise it doesn't reflect correctly in the interface method signature. Should I skip the optional parameter and just use a nullable type? Or will this work as intended with no side effects or consequences?

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  • How can I select all records between two dates without using date fields?

    - by Hayden Bech
    Hi, I have a MySQL DB and I need to be able to store dates earlier then 1970 - in my case, as early as 0 AD and earlier too, so I need a custom way to store dates. I have thought to use this format: Year - int(6) | Month -int(2) | day - int (2) | time - time | AD tinyint (1) | mya - int (11) But when it comes to actually using data in this format it becomes difficult. For example, if I want to get all records between two dates it would be like (pseudocode not SQL): get all where year between minYear and maxYear if year == minYear, month = minMonth if year == maxYear, month <= maxMonth if month == minMonth, day = minDay if month == maxMonth, day <= maxDay if day == minDay, time = minTime if day == maxDay, time <= maxTime or something, which seems like a right pain. I could store seconds before/after 0 AD, but that would take up way too much data! 2010 (EDIT: 2011) = 6.4 billion seconds since 0 AD. Does anybody have any ideas for this problem?

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  • How to wrap a C function whose parameters are pointer to structs, so that it can be called from Lua?

    - by pierr
    I have the follwing C function. How should I wrap it so it can be called from a Lua script? typedef struct tagT{ int a ; int b ; } type_t; int lib_a_f_4(type_t *t) { return t->a * t->b ; } I know how to wrapr it if the function parameter type were int or char *. Should I use table type for a C structure? EDIT: I am using SWIG for the wraping , according to this doc, It seems that I should automatically have this funtion new_type_t(2,3) , but it is not the case. If you wrap a C structure, it is also mapped to a Lua userdata. By adding a metatable to the userdata, this provides a very natural interface. For example, struct Point{ int x,y; }; is used as follows: p=example.new_Point() p.x=3 p.y=5 print(p.x,p.y) 3 5 Similar access is provided for unions and the data members of C++ classes. C structures are created using a function new_Point(), but for C++ classes are created using just the name Point().

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  • How do I determine if a property was overriden?

    - by Benjamin
    Hello I am doing a project that where I need to register all the properties, because of the system being so huge it would require a lot of work to register all the properties that i want to be dependent for the purpose of Xaml. The goal is to find all properties that are on the top of the tree. so basically public class A{ public int Property1 { get; set; } } public class B : A{ public int Property2 { get; set; } public virtual int Property3 { get; set; } } public class C : B{ public override int Property3 { get; set; } public int Property4 { get; set; } public int Property5 { get; set; } } The end result would be something like this A.Prorperty1 B.Property2 B.Property3 C.Property4 C.Property5 If you notice I don't want to accept overridden properties because of the way I search for the properties if I do something like this C.Property3 for example and it cannot find it it will check C's basetype and there it will find it. This is what I have so far. public static void RegisterType( Type type ) { PropertyInfo[] properties = type.GetProperties( BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly | BindingFlags.GetProperty | BindingFlags.SetProperty ); if ( properties != null && properties.Length > 0 ) { foreach ( PropertyInfo property in properties ) { // if the property is an indexers then we ignore them if ( property.Name == "Item" && property.GetIndexParameters().Length > 0 ) continue; // We don't want Arrays or Generic Property Types if ( (property.PropertyType.IsArray || property.PropertyType.IsGenericType) ) continue; // Register Property } } } What I want are the following: Public properties, that are not overridden, not static, not private Either get and set properties are allowed They are not an array or a generic type They are the top of the tree ie C class in the example is the highest (The property list example is exactly what I am looking for) They are not an indexer property ( this[index] ) Any help will be much appreciated =).

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  • Prevent Negative numbers for Age without using client side validation.

    - by Deepak
    Hi People, I have an issue in Core java. Consider the Employee class having an attribute called age. class Employee{ private int age; public void setAge(int age); } My question is how do i restrict/prevent setAge(int age) method such that it accepts only positive numbers and it should not allow negative numbers, Note: This has to be done without using client side validation.how do i achieve it using Java/server side Validation only.The validation for age attribute should be handled such that no exception is thrown

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  • Is generating real random numbers this easy in C#?

    - by JL
    I found this code using Google. private int RandomNumber(int min, int max) { Random random = new Random(); return random.Next(min, max); } Is this really all there is to generating REAL random numbers in C#? I intend to generate on a small scale between values 1-10. Thanks

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  • linq min question/bug

    - by jdelator
    Anyone care to guess what currentIndex is at the end of execution? int[] ints = new int[] { -1, 12, 26, 41, 52, -1, -1 }; int currentIndex = ints.Min(); It's 110. Does anyone know why?

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  • MYSQL Inserting rows that reference main rows.

    - by Andrew M
    I'm transferring my access logs into a database. I've got two tables: urlRequests id : int(10) host : varchar(100) path: varchar(300) unique index (host, path) urlAccesses id : int(10) request : int(10) <-- reference to urlRequests row ip : int(4) query : varchar(300) time : timestamp I need to insert a row into urlAccesses for every page load, but first a row in urlRequests has to exist with the requested host and path so that urlAccesses's row can reference it. I know I can do it this way: A. check if a row exists in urlRequests B. insert a row in urlRequests if it needs it C. insert a row into urlAccesses with the urlRequests's row id referenced That's three queries for every page load if the urlRequests row doesn't exist. I'm very new to MySQL, so I'm guessing that there's a way to go about this that would be faster and use less queries.

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  • Find groups with both validated, unvalidated users

    - by Matchu
    (Not my real MySQL schema, but illustrates what needs done.) Users can belong to many groups, and groups have many users. users: id INT validated TINYINT(1) groups: id INT name VARCHAR(20) groups_users: group_id INT user_id INT I need to find groups that contain both validated and unvalidated users (validated being 1 or 0, respectively), in order to perform a specific manual maintenance task. There are thousands of users, all belong to at least one group, but a group usually only has 2-5 users. This is a live production server, so I could probably craft a query myself, but the last one I tried took a matter of minutes before I killed it. (I'm not one of those brilliant SQL wizards.) I suppose I could take the server down for maintenance, but, if possible, a query that gets this job done in a matter of seconds would be fantastic. Thanks!

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  • timer_getoverrun() doesn't behave as expected when using sleep()

    - by dlp
    Here is a program that uses a POSIX per-process timer alongside the sleep subroutine. The signal used by the timer has been set to SIGUSR1 rather than SIGALRM, since SIGALRM may be used internally by sleep, but it still doesn't seem to work. I have run the program using the command line timer-overruns -d 1 -n 10000000 (1 cs interval) so, in theory, we should expect 100 overruns between calls to sigwaitinfo. However, timer_getoverrun returns 0. I have also tried a version using a time-consuming for loop to introduce the delay. In this case, overruns are recorded. Does anyone know why this happens? I am running a 3.4 Linux kernel. Program source /* * timer-overruns.c */ #include <unistd.h> #include <stdlib.h> #include <stdio.h> #include <signal.h> #include <time.h> // Signal to be used for timer expirations #define TIMER_SIGNAL SIGUSR1 int main(int argc, char **argv) { int opt; int d = 0; int r = 0; // Repeat indefinitely struct itimerspec its; its.it_interval.tv_sec = 0; its.it_interval.tv_nsec = 0; // Parse arguments while ((opt = getopt(argc, argv, "d:r:s:n:")) != -1) { switch (opt) { case 'd': // Delay before calling sigwaitinfo() d = atoi(optarg); break; case 'r': // Number of times to call sigwaitinfo() r = atoi(optarg); break; case 's': // Timer interval (seconds) its.it_interval.tv_sec = its.it_value.tv_sec = atoi(optarg); break; case 'n': // Timer interval (nanoseconds) its.it_interval.tv_nsec = its.it_value.tv_nsec = atoi(optarg); break; default: /* '?' */ fprintf(stderr, "Usage: %s [-d signal_accept_delay] [-r repetitions] [-s interval_seconds] [-n interval_nanoseconds]\n", argv[0]); exit(EXIT_FAILURE); } } // Check sanity of command line arguments short e = 0; if (d < 0) { fprintf(stderr, "Delay (-d) cannot be negative!\n"); e++; } if (r < 0) { fprintf(stderr, "Number of repetitions (-r) cannot be negative!\n"); e++; } if (its.it_interval.tv_sec < 0) { fprintf(stderr, "Interval seconds value (-s) cannot be negative!\n"); e++; } if (its.it_interval.tv_nsec < 0) { fprintf(stderr, "Interval nanoseconds value (-n) cannot be negative!\n"); e++; } if (its.it_interval.tv_nsec > 999999999) { fprintf(stderr, "Interval nanoseconds value (-n) must be < 1 second.\n"); e++; } if (e > 0) exit(EXIT_FAILURE); // Set default values if not specified if (its.it_interval.tv_sec == 0 && its.it_interval.tv_nsec == 0) { its.it_interval.tv_sec = its.it_value.tv_sec = 1; its.it_value.tv_nsec = 0; } printf("Running with timer delay %d.%09d seconds\n", (int) its.it_interval.tv_sec, (int) its.it_interval.tv_nsec); // Will be waiting for signals synchronously, so block the one in use. sigset_t sigset; sigemptyset(&sigset); sigaddset(&sigset, TIMER_SIGNAL); sigprocmask(SIG_BLOCK, &sigset, NULL ); // Create and arm the timer struct sigevent sev; timer_t timer; sev.sigev_notify = SIGEV_SIGNAL; sev.sigev_signo = TIMER_SIGNAL; sev.sigev_value.sival_ptr = timer; timer_create(CLOCK_REALTIME, &sev, &timer); timer_settime(timer, TIMER_ABSTIME, &its, NULL ); // Signal handling loop int overruns; siginfo_t si; // Make the loop infinite if r = 0 if (r == 0) r = -1; while (r != 0) { // Sleeping should cause overruns if (d > 0) sleep(d); sigwaitinfo(&sigset, &si); // Check that the signal is from the timer if (si.si_code != SI_TIMER) continue; overruns = timer_getoverrun(timer); if (overruns > 0) { printf("Timer overrun occurred for %d expirations.\n", overruns); } // Decrement r if not repeating indefinitely if (r > 0) r--; } return EXIT_SUCCESS; }

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