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  • What is a truly empty std::vector in C++?

    - by RyanG
    I've got a two vectors in class A that contain other class objects B and C. I know exactly how many elements these vectors are supposed to hold at maximum. In the initializer list of class A's constructor, I initialize these vectors to their max sizes (constants). If I understand this correctly, I now have a vector of objects of class B that have been initialized using their default constructor. Right? When I wrote this code, I thought this was the only way to deal with things. However, I've since learned about std::vector.reserve() and I'd like to achieve something different. I'd like to allocate memory for these vectors to grow as large as possible because adding to them is controlled by user-input, so I don't want frequent resizings. However, I iterate through this vector many, many times per second and I only currently work on objects I've flagged as "active". To have to check a boolean member of class B/C on ever iteration is silly. I don't want these objects to even BE there for my iterators to see when I run through this list. Is reserving the max space ahead of time and using push_back to add a new object to the vector a solution to this?

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  • Automated browser testing: How to test JavaScript in web pages?

    - by Dave
    I am trying to write an application that will test a series of web-pages programmatically. The web pages being tested have JavaScript embedded within them which alter the structure of the HTML when they complete execution. It is then the goal to take the final HTML (post-execution of the embedded JavaScript) and compare it against a known output. Essentially, the Input --- Output for the test application is: URL ---[retrieve HTML]--- HTML ---[execute JS, then compare]--- PASS/FAIL Here is the challenge: I have been unable to find a solution that is able to take the HTML I retrieve from the URL and process the JavaScript, as a browser would, and generate the final HTML a user might see from "View Source" on the same page within the browser. It would be very surprising if this sort of approach has not been made before, so I'm hoping someone out there knows of a fitting solution for this application/problem? If at all possible, I'm hoping for a solution that integrates with .NET (I've tried using the WebBrowser, with no luck). However, if there is an existing 3rd party application that can do exactly this, that would be quite acceptable. Thanks in advance for the suggestions! Dave

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  • Setting the mysql root user password on mac

    - by madaura
    I just Install MySQL on Mac OS X. The next step was setting the root user password, do I did the next: 1-Launch the terminal app to access the unix command line. 2-Under the unix prompt I executed the next commands: madaura$ cd /usr/local/mysql/bin madaura$ ./mysqladmin -u root password 'password' But, when I execute the command madaura$ ./mysql -u root, this is the answer: Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 224 Server version: 5.5.13 MySQL Community Server (GPL) Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> I can get in to the mysql command line without password! Any ideas? Thanks a lot!

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  • R from java with no graphics: is it worth moving to JRI

    - by LH
    I have a system set up that's been happily running R from a java servlet, spawning processed & hooking into the process's stdin, stdout, and stderr streams, as in the second andwer to this question. After a system upgrade (that included glibc), the input is no longer reaching the R process.* Until now, 'R --vanilla --slave -f [file] ...' was working fine for me. I also have no swing dependencies right now, so I'm somewhat reluctant to add them. (I may actually not be able to add swing dependencies; am I right that using REngine automatically brings swing in? The examples import all of swing.) Are there advantages to switching to JRI? What changes would I need to make to my R script? (It currently reads from stdin and writes to stdout). I'm not finding the provided examples terribly helpful for how to use JRI in this situation. Thanks for your help & comments. *I can't even tell if the problem is data being written too soon or too late, but that's a separate issue/question; if I move to JRI I'm hoping it all becomes moot.

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  • Radio button is not funtioning

    - by user3614421
    I'm having problem with my radio button in my gridview. I want to select any row one by one so that I can perform UPDATE, DELETE, and DISPLAY the row. When I select the button, the page will be refreshed and the button I selected before is not selected anymore. So I can't click any menu to update, delete or display the row. I noticed this is happening when I set the Autopostback = "True". How can I solve it? Any idea? Below are my codes: Page: <script language="javascript" type="text/javascript"> function radiobtn(id) { var rdBtn = document.getElementById(id); var List = document.getElementsByTagName("input"); for (i = 0; i < List.length; i++) { if (List[i].type == "radio" && List[i].id != rdBtn.id) { List[i].checked = false; } } } </script> <asp:RadioButton ID="CheckDel" runat="server" onclick="javascript:radiobtn(this.id)" OnCheckedChanged="CheckDel_CheckedChanged" AutoPostBack="True" /> server end: protected void CheckDel_CheckedChanged(object sender, EventArgs e) { CheckBox chkStatus = (CheckBox)sender; GridViewRow row = (GridViewRow)chkStatus.NamingContainer; Session["datestart"] = row.Cells[1].Text; Session["empid"] = row.Cells[2].Text; Session["empname"] = row.Cells[3].Text; Session["days"] = row.Cells[4].Text; Session["leavetype"] = row.Cells[5].Text; Session["leavestatus"] = row.Cells[6].Text; bool status = chkStatus.Checked; } Please help

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  • optimization math computation (multiplication and summing)

    - by wiso
    Suppose you want to compute the sum of the square of the differences of items: $\sum_{i=1}^{N-1} (x_i - x_{i+1})^2$, the simplest code (the input is std::vector<double> xs, the ouput sum2) is: double sum2 = 0.; double prev = xs[0]; for (vector::const_iterator i = xs.begin() + 1; i != xs.end(); ++i) { sum2 += (prev - (*i)) * (prev - (*i)); // only 1 - with compiler optimization prev = (*i); } I hope that the compiler do the optimization in the comment above. If N is the length of xs you have N-1 multiplications and 2N-3 sums (sums means + or -). Now suppose you know this variable: sum = $x_1^2 + x_N^2 + 2 sum_{i=2}^{N-1} x_i^2$ Expanding the binomial square: $sum_i^{N-1} (x_i-x_{i+1})^2 = sum - 2\sum_{i=1}^{N-1} x_i x_{i+1}$ so the code becomes: double sum2 = 0.; double prev = xs[0]; for (vector::const_iterator i = xs.begin() + 1; i != xs.end(); ++i) { sum2 += (*i) * prev; prev = (*i); } sum2 = -sum2 * 2. + sum; Here I have N multiplications and N-1 additions. In my case N is about 100. Well, compiling with g++ -O2 I got no speed up (I try calling the inlined function 2M times), why?

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  • In Perl, how to match several prefixes

    - by xorsyst
    I have 2 input files. One is a list of prefix and lengths, like this: 101xxx 102xxx 30xx 31xx (where x is any number) And another is a list of numbers. I want to iterate through the second file, matching each number against any of the prefix/lengths. This is fairly easy. I build a list of regexps: my @regexps = ('101...', '102...', '30..', '31..'); Then: foreach my $regexp (@regexps) { if (/$regexp/) { # do something But, as you can guess, this is slow for a long list. I could convert this to a single regexp: my $super_regexp = '101...|102...|30..|31..'; ...but, what I need is to know which regexp matched the item, and what the ..s matched. I tried this: my $catching_regexp = '(101)(...)|(102)(...)|(30)(..)|(31)(..)'; but then I don't know whether to look in $1, $3, %5 or $7. Any ideas? How can I match against any of these prefix/lengths and know which prefix, and what the remaining digits where?

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  • JSON element detection

    - by user3614570
    I’ve created a string… {"atts": [{"name": "wedw"}, {"type": "---"}]} I pile a bunch of these together in an array based on user input and attach them to another string to complete a JSON object that tests out as valid. So I end up with a global array called fields with a bunch of these little snippets. So how do I change the name "weds" with a new name? I’ve tried... function changefieldname(pos){ var obj = JSON.parse(jsonstring); var oldname = obj.tracelog.fields[pos].atts[0]["name"]; var newname = document.getElementById("newlogfieldname"+pos).value; fields[pos].replace(oldname, newname); //writejson(); } And a bunch of variations. I know everything is checking out correct interms of the variables pos, oldname, and newname. I also know that fields[pos] returns the string in the array I want to correct but it’s not happy. I also tried converting fields[pos] to a string, but the replace function doesn't work on it. I’m sure there is a good reason.

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  • Javascript for disabling dropdown in ASP.NET

    - by Lijo
    Hi Team, I am using JScript in ASP.NET 2005. I have a page with a checkbox and a dropdown list. When the checkbox is checked the dropdown is to be disabled. During Postback of the page this should be retained. I am using a javascript function as follows if((chkOwner[1].checked==true)) { document.getElementById(ddlClientID).disabled=true; document.getElementById(ddlClientID).className = "form-disabled"; document.getElementById(ddlClientID).selectedIndex = 0; } else { document.getElementById(ddlClientID).disabled=false; document.getElementById(ddlClientID).className = "form-input"; document.getElementById(ddlClientID).selectedIndex = 0; } This works, almost. However, the dropdown selection is not retained after postback (when checkbox is not selected). Apprently the solution is to remove the last line, i.e, in the else part, remove the selectedIndex =0 setting. But, when I do that the disabling of dropdown (when check box is selected) is not working after post back. Could you please help on this? Thanks Lijo

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  • How to separate date in php

    - by user225269
    I want to be able to separate the birthday from the mysql data into day, year and month. Using the 3 textbox in html. How do I separate it? I'm trying to think of what can I do with the code below to show the result that I want: Here's the html form with the php code: $idnum = mysql_real_escape_string($_POST['idnum']); mysql_select_db("school", $con); $result = mysql_query("SELECT * FROM student WHERE IDNO='$idnum'"); $month = mysql_real_escape_string($_POST['mm']); ?> <?php while ( $row = mysql_fetch_array($result) ) { ?> <tr> <td width="30" height="35"><font size="2">Month:</td> <td width="30"><input name="mo" type="text" id="mo" onkeypress="return handleEnter(this, event)" value="<?php echo $month = explode("-",$row['BIRTHDAY']);?>"> As you can see the column is the mysql database is called BIRTHDAY. With this format: YYYY-MM-DD How do I do it. So that the data from the single column will be divided into three parts? Please help thanks,

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  • OpenGL multiple threads, variable handling [closed]

    - by toeplitz
    I have written an OpenGL program which runs in the following way: Main: - Initialize SDL - Create thread which has the OpenGL context: - Renderloop - Set camera (view) matrix with glUniform. - glDrawElements() .... etc. - Swapbuffers(); - Main SDL loop handling input events and such. - Update camera matrix of type glm::mat4. This is how I pass my camera object to the class that handles opengl. Camera *cam = new Camera(); gl.setCam(cam); where void setCam(Camera *camera) { this->camera = camera; } For rendering in the opengl context thread, this happens: glm::mat4 modelView = camera->view * model; glUniformMatrix4fv(shader->bindUniform("modelView"), 1, GL_FALSE, glm::value_ptr(modelView)); In the main program where my SDL and other things are handles I then recompute the view matrix. This his working fine without me using any mutex locks. Is this correct? On the other hand, I add objects to my scene by an "upload queue" and in this case I have to mutex lock my upload queue vector (vector class type) when adding items to it or else the program crashes. In summary: I recompute my matrix in a different thread and then use it in the opengl thread without any mutex lock. Why is this working? Edit: I think my question is similar to what was asked here: Should I lock a variable in one thread if I only need it's value in other threads, and why does it work if I don't?, only in my case it is even more simple with only one matrix being changed.

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  • Problem with inherited classes in C#

    - by Unniloct
    I have a class called "Entity," with two child classes: "Creature" and "Item." (I'm making a game.) Creature has two functions called "Attack," one for attacking Creatures, and one for attacking Items. So far, everything works well. Now I'm working on the shooting bit, so I have a function called SelectTarget(). It takes all of the Entities (both Creatures and Items) in the player's view that the player can shoot and lets the player choose one. So here lies the problem: SelectTarget() returns an Entity, but I need some code to figure out whether that Entity is a Creature or an Item, and process it appropriately. Since this question looks kind of empty without any code, and I'm not 100% sure my explanation is good enough, here's where I'm at: if (Input.Check(Key.Fire)) { Entity target = Game.State.SelectTarget.Run(); this.Draw(); if (target != null) { //Player.Attack(target); // This won't work, because I have: // Player.Attack((Creature)Target) // Player.Attack((Item)Target) // but nothing for Entity, the parent class to Creature and Item. return true; } } (If the way the game is laid out seems weird, it's a roguelike.)

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  • Problem with changing td's html in JQuery.

    - by bugbug
    I want to change text in table td from 1,1,1 to 1,2,3 with following code, But it not seem to work. what is wrong in my code? This is my JavaScript function. function reorder(targetId){ var i = 1; jQuery.find(targetId).each(function(){ jQuery(this).attr("innerHTML", i); i ++; }); } My html code. <form> <input type="button" onClick="reorder('#index');" value="test"/> <table> <tr><td id="index">1</td></tr> <tr><td id="index">1</td></tr> <tr><td id="index">1</td></tr> </table> </form>

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  • Stop functions in 5 minutes if they dont end running

    - by george mano
    I want to add a feature in my project. I have 2 functions running in a for-loop because I want to find the solution of the functions in random arrays. I also have an function that makes random arrays. In each loop the array that is made by the random_array fun are the input of the 2 functions. The 2 functions print solutions in the screen , they dont return an argument. int main(){ for (i=0;i<50 i++) { arr1=ramdom_array(); func1(arr1) func2(arr1) } } I need to stop the functions running if they have not ended in 5 minutes. I have thought that I have to put in the functions something like this : void func1(array<array<int,4>,4> initial) { while (5minutes_not_passed) { //do staff if(solution==true) break; } } But I dont know what to put in the 5minutes_not_passed. the declaration of the functions are like this: void func1(array<array<int,4>,4> initial) void func2(array<array<int,4>,4> initial) I have found that I can use the thread library but I dont think meshing up with threads in a good idea. I believe something like a timer is needed. Note that the functions sometimes might end before 5 minutes.

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  • Why does cloning the django inline formsets result to forms with similar ids and names?

    - by user1289167
    In my project I use django inline formsets. I got the jquery to clone the formsets but unfortunately the cloned forms have the same names and ids and so data entered in the last one overwrites the data from the first form. What could I be doing wrong? Here is the script: <script type="text/javascript">> function cloneMore(selector, type) { var newElement = $(selector).clone(true); var total = $('#id_' + type + '-TOTAL_FORMS').val(); newElement.find(':input').each(function() { var name = $(this).attr('name').replace('-' + (total-1) + '-','-' + total + '-'); var id = 'id_' + name; $(this).attr({'name': name, 'id': id}).val('').removeAttr('checked'); }); newElement.find('label').each(function() { var newFor = $(this).attr('for').replace('-' + (total-1) + '-','-' + total + '-'); $(this).attr('for', newFor); }); total++; $('#id_' + type + '-TOTAL_FORMS').val(total); $(selector).after(newElement); } </script>

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  • Implementing search functionality with multiple optional parameters against database table.

    - by quarkX
    Hello, I would like to check if there is a preferred design pattern for implementing search functionality with multiple optional parameters against database table where the access to the database should be only via stored procedures. The targeted platform is .Net with SQL 2005, 2008 backend, but I think this is pretty generic problem. For example, we have customer table and we want to provide search functionality to the UI for different parameters, like customer Type, customer State, customer Zip, etc., and all of them are optional and can be selected in any combinations. In other words, the user can search by customerType only or by customerType, customerZIp or any other possible combinations. There are several available design approaches, but all of them have some disadvantages and I would like to ask if there is a preferred design among them or if there is another approach. Generate sql where clause sql statement dynamically in the business tier, based on the search request from the UI, and pass it to a stored procedure as parameter. Something like @Where = ‘where CustomerZip = 111111’ Inside the stored procedure generate dynamic sql statement and execute it with sp_executesql. Disadvantage: dynamic sql, sql injection Implement a stored procedure with multiple input parameters, representing the search fields from the UI, and use the following construction for selecting the records only for the requested fields in the where statement. WHERE (CustomerType = @CustomerType OR @CustomerType is null ) AND (CustomerZip = @CustomerZip OR @CustomerZip is null ) AND ………………………………………… Disadvantage: possible performance issue for the sql. 3.Implement separate stored procedure for each search parameter combinations. Disadvantage: The number of stored procedures will increase rapidly with the increase of the search parameters, repeated code.

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  • Maintaining Mouse Control in Embedded swfs (i.e. parent / child ) Flash cs4 AS3

    - by garydev
    Hello to all, I have an issue that is driving me nuts. I have an AS3 application that performs a calculation based upon user's input to determine a result. The purpose is to predict the results of a horse's coat color based on the genetics. The results are given in a 3d model swfs that are loaded into the "shell's" UILoader Component and they rotate. I have an example of this here: http://www.provideoshow.com/coatcalculator/coat_calculator.html As you can see this works fine with an "auto-rotate" feature. The problem is that my client wants the 3d models to be rotated by the user's mouse. I have the 3d models rotating with the mouse but they only work when they are stand alone swfs. They break when they are loaded into the shell. Some research informs me that the issue is in the stage properties and the parent not receiving them from the child. I've gotten some advice that I need to pass a reference to the shell's stage and preferably in the init function. This is the code I have in the child which is loaded as a class public function Main_master_withmouse() { if(stage) { _stage = stage; init(stage); } } protected function init(rootStage:Stage):void { if(rootStage) { _stage = rootStage; } else { _stage = this.stage; } sceneWidth = _stage.stageWidth createChildren(); startRendering(); } I can't figure out what to put in the parent to pass the reference to its stage. Any help is greatly appreciated. Thank you in advance

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  • Is there a way in VS2008 (c#) to see all the possible exception types that can originate from a meth

    - by Matt
    Is there a way in VS2008 IDE for c# to see all the possible exception types that can possibly originate from a method call or even for an entire try-catch block? I know that intellisense or the object browser tells me this method can throw these types of exceptions but is there another way than using the object browser everytime? Something more accessible when coding? Furthermore, I don't think intellisense or the object browser do anything more than read the XML code comments. Shouldn't it be possible to scan a class's source and find all the exception types that can be thrown. (Forget path-ing based on method input, just scan the code for exception types) Am I wrong? Extending this idea, you should be able to hover over the 'try' or 'catch' keywords and present a tooltip with all the types of exceptions that can be thrown. My question boils down to, does a VS2008 add on like this exist? Does VS2010 do this perhaps? If not, could you implement it the way I've described, by scanning the class code for thrown exception types and would people find it useful. Exceptions bubble up so you have to scan every bit of code every method call, which I guess could be impractical, though I suppose you could build an index the first time and increase your speed that way. (It might be a cool little project....)

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  • CodeGolf: Find the Unique Paths

    - by st0le
    Here's a pretty simple idea, in this pastebin I've posted some pair of numbers. These represent Nodes of a directed graph. The input to stdin will be of the form, (they'll be numbers, i'll be using an example here) c d q r a b b c d e p q so x y means x is connected to y (not viceversa) There are 2 paths in that example. a->b->c->d->e and p->q->r. You need to print all the unique paths from that graph The output should be of the format a->b->c->d->e p->q->r Notes You can assume the numbers are chosen such that one path doesn't intersect the other (one node belongs to one path) The pairs are in random order. They are more than 1 paths, they can be of different lengths. All numbers are less than 1000. If you need more details, please leave a comment. I'll amend as required. Shameless-Plug For those who enjoy Codegolf, please Commit at Area51 for its very own site:) (for those who don't enjoy it, please support it as well, so we'll stay out of your way...)

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  • get the right id of a record in database in each click on the edit button

    - by kawtousse
    hi every one, i am facing a big problem right now. I have a html table in each row i have a button called edit allowing user to relod the form with parameter that he has selected. for this i define a hidden type to get the id of the record in database to access to various colonne and to refresh the form with those parameters. My challenge now is how to get the right id in every click on the edit button to let me after to get the right record and to update it in the data base. I am preceeding like the following: retour.append("<td style=border-right:#FFF bordercolor=#FFFFFF>"); retour.append("<input type=\"hidden\" id=\"id_"+nomTab+"_"+compteur+"\" value=\""+object.getIdDailyTimeSheet()+"\" name=\"hd"+compteur+"\" />"); retour.append("<button id=edit name=edit type=button onClick= editarow()>"); retour.append("<img src=edit.gif />"); retour.append("</button>"); retour.append("</td>"); i realise the submit in javascript and i want to get the idDailyTimesheet everyonce the user click the submit button. thanks for help.

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  • How to get correct children ids using fields_for "parents[]", parent do |f| using f.fields_for :children, child ?

    - by Anatortoise House
    I'm editing multiple instances of a parent model in an index view in one form, as in Railscasts #198. Each parent has_many :children and accepts_nested_attributes_for :children, as in Railscasts #196 and #197 <%= form_tag %> <% for parent in @parents %> <%= fields_for "parents[]", parent do |f| <%= f.text_field :job %> <%= f.fields_for :children do |cf| %> <% cf.text_field :chore %> <% end %> <% end %> <% end %> <% end %> Given parent.id==1 f.text_field :job correctly generates <input id="parents_1_job" type="text" value="coding" size="30" name="parents[1][job]"> But cf.text_field :chore generates ids and names that don't have the parent index. id="parents_children_attributes_0_chore" name="parents[children_attributes][0][chore]" If I try passing the specific child object to f.fields_for like this: <% for child in parent.children %> <%= f.fields_for :children, child do |cf| %> <%= cf.text_field :chore %> <% end %> <% end %> I get the same. If I change the method from :children to "[]children" I get id="parents_1___children_chore" which gets the right parent_index but doesn't provide an array slot for the child index. "[]children[]" isn't right either: id="parents_1__children_3_chore" as I was expecting attributes_0_chore instead of 3_chore. Do I need to directly modify an attribute of the FormBuilder object, or subclass FormBuilder to make this work, or is there a syntax that fits this situation? Thanks for any thoughts.

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  • SQL inner join from field defined table?

    - by Wolftousen
    I have a, currently, a total of 6 tables that are part of this question. The primary table, tableA, contains columns that all the entries in the other 5 tables have in common. The other 5 tables have columns which define the entry in tableA in more detail. For example: TableA ID|Name|Volumn|Weight|Description 0 |T1 |0.4 |0.1 |Random text 1 |R1 |5.3 |25 |Random text TableB ID|Color|Shape 0 |Blue |Sphere TableC ID|Direction|Velocity 1 |North |3.4 (column names are just examples don't take them for what they mean...) The ID field in Table A is unique to all other tables (i.e. TableB will have 0, but TableC will not, nor any other Tables). What I would like to do is select all the fields from TableA and the corresponding (according to ID field) detail Table (TableB-F). What I have currently done and not tested is added a field to TableA so it looks like this: TableA ID|Name|Volumn|Weight|Description|Table 0 |T1 |0.4 |0.1 |Random text|TableB 1 |R1 |5.3 |25 |Random text|TableC I have a few questions about this: 1.Is it proper to do such a thing to TableA, as foreign keys wont work in this situation since they all need to link to different tables? 2.If this is proper, would the SQL query look like this (ID would be input by the user)? SELECT * FROM TableA AS a INNER JOIN a.Table AS t ON a.ID = ID; 3.Is there a better way to do this? Thanks for the help.

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  • Optimal (Time paradigm) solution to check variable within boundary

    - by kumar_m_kiran
    Hi All, Sorry if the question is very naive. I will have to check the below condition in my code 0 < x < y i.e code similar to if(x > 0 && x < y) The basic problem at system level is - currently, for every call (Telecom domain terminology), my existing code is hit (many times). So performance is very very critical, Now, I need to add a check for boundary checking (at many location - but different boundary comparison at each location). At very normal level of coding, the above comparison would look very naive without any issue. However, when added over my statistics module (which is dipped many times), performance will go down. So I would like to know the best possible way to handle the above scenario (kind of optimal way for limits checking technique). Like for example, if bit comparison works better than normal comparison or can both the comparison be evaluation in shorter time span? Other Info x is unsigned integer (which must be checked to be greater than 0 and less than y). y is unsigned integer. y is a non-const and varies for every comparison. Here time is the constraint compared to space. Language - C++. Now, later if I need to change the attribute of y to a float/double, would there be another way to optimize the check (i.e will the suggested optimal technique for integer become non-optimal solution when y is changed to float/double). Thanks in advance for any input. PS : OS used is SUSE 10 64 bit x64_64, AIX 5.3 64 bit, HP UX 11.1 A 64.

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  • Questions about shifting from mysql to PDO

    - by Scarface
    Hey guys I have recently decided to switch all my current plain mysql queries performed with php mysql_query to PDO style queries to improve performance, portability and security. I just have some quick questions for any experts in this database interaction tool Will it prevent injection if all statements are prepared? (I noticed on php.net it wrote 'however, if other portions of the query are being built up with unescaped input, SQL injection is still possible' I was not exactly sure what this meant). Does this just mean that if all variables are run through a prepare function it is safe, and if some are directly inserted then it is not? Currently I have a connection at the top of my page and queries performed during the rest of the page. I took a look at PDO in more detail and noticed that there is a try and catch procedure for every query involving a connection and the closing of that connection. Is there a straightforward way to connecting and then reusing that connection without having to put everything in a try or constantly repeat the procedure by connecting, querying and closing? Can anyone briefly explain in layman's terms what purpose a set_exception_handler serves? I appreciate any advice from any more experienced individuals.

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  • What goes into the "Controller" in "MVC"?

    - by P72endragon
    I think I understand the basic concepts of MVC - the Model contains the data and behaviour of the application, the View is responsible for displaying it to the user and the Controller deals with user input. What I'm uncertain about is exactly what goes in the Controller. Lets say for example I have a fairly simple application (I'm specifically thinking Java, but I suppose the same principles apply elsewhere). I organise my code into 3 packages called app.model, app.view and app.controller. Within the app.model package, I have a few classes that reflect the actual behaviour of the application. These extends Observable and use setChanged() and notifyObservers() to trigger the views to update when appropriate. The app.view package has a class (or several classes for different types of display) that uses javax.swing components to handle the display. Some of these components need to feed back into the Model. If I understand correctly, the View shouldn't have anything to do with the feedback - that should be dealt with by the Controller. So what do I actually put in the Controller? Do I put the public void actionPerformed(ActionEvent e) in the View with just a call to a method in the Controller? If so, should any validation etc be done in the Controller? If so, how do I feedback error messages back to the View - should that go through the Model again, or should the Controller just send it straight back to View? If the validation is done in the View, what do I put in the Controller? Sorry for the long question, I just wanted to document my understanding of the process and hopefully someone can clarify this issue for me!

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