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  • Beginner's Question about accessing mysql using OOP

    - by user345690
    I am reading the PHP and mySQL web development book and so far been doing all the PHP and mysql using procedural. But then it talks about accessing mysql with objects. This works for me: //I define $db so can connect $query="select * FROM testing"; $result=mysqli_query($db,$query); while($row=mysqli_fetch_array($result)){ //echo the data } But when I try to do it with classes, it doesn't $query="select * FROM testing"; $result=$db->query($query); $row=$result->fetch_assoc(); Do I have to write my own class so it defines what query and fetch_assoc does? Or what?

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  • Fastest method for SQL Server inserts, updates, selects

    - by Ian
    I use SPs and this isn't an SP vs code-behind "Build your SQL command" question. I'm looking for a high-throughput method for a backend app that handles many small transactions. I use SQLDataReader for most of the returns since forward only works in most cases for me. I've seen it done many ways, and used most of them myself. Methods that define and accept the stored procedure parameters as parameters themselves and build using cmd.Parameters.Add (with or without specifying the DB value type and/or length) Assembling your SP params and their values into an array or hashtable, then passing to a more abstract method that parses the collection and then runs cmd.Parameters.Add Classes that represent tables, initializing the class upon need, setting the public properties that represent the table fields, and calling methods like Save, Load, etc I'm sure there are others I've seen but can't think of at the moment as well. I'm open to all suggestions.

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  • Show me some cool python list comprehensions

    - by christangrant
    One of the major strengths of python and a few other (functional) programming languages are the list comprehension. They allow programmers to write complex expressions in 1 line. They may be confusing at first but if one gets used to the syntax, it is much better than nested complicated for loops. With that said, please share with me some of the coolest uses of list comprehensions. (By cool, I just mean useful) It could be for some programming contest, or a production system. For example: To do the transpose of a matrix mat >>> mat = [ ... [1, 2, 3], ... [4, 5, 6], ... [7, 8, 9], ... ] >>> [[row[i] for row in mat] for i in [0, 1, 2]] [[1, 4, 7], [2, 5, 8], [3, 6, 9]] Please include a description of the expression and where it was used (if possible).

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  • Rails find by *all* associated tags.id in

    - by mark
    Hi Say I have a model Taggable has_many tags, how may I find all taggables by their associated tag's taggable_id field? Taggable.find(:all, :joins => :tags, :conditions => {:tags => {:taggable_id => [1,2,3]}}) results in this: SELECT `taggables`.* FROM `taggables` INNER JOIN `tags` ON tags.taggable_id = taggables.id WHERE (`tag`.`taggable_id` IN (1,2,3)) The syntax is incredible but does not fit my needs in that the resulting sql returns any taggable that has any, some or all of the tags. How can I find taggables with related tags of field taggable_id valued 1, 2 and 3? Thanks for any advice. :)

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  • How do you extend a Ruby module with macro-like metaprogramming methods?

    - by Ian Terrell
    Consider the following extension (the pattern popularized by several Rails plugins over the years): module Extension def self.included(recipient) recipient.extend ClassMethods recipient.class_eval { include InstanceMethods } end module ClassMethods def macro_method puts "Called macro_method within #{self.name}" end end module InstanceMethods def instance_method puts "Called instance_method within #{self.object_id}" end end end If you wished to expose this to every class, you can do the following: Object.send :include, Extension Now you can define any class and use the macro method: class FooClass macro_method end #=> Called macro_method within FooClass And instances can use the instance methods: FooClass.new.instance_method #=> Called instance_method within 2148182320 But even though Module.is_a?(Object), you cannot use the macro method in a module: module FooModule macro_method end #=> undefined local variable or method `macro_method' for FooModule:Module (NameError) This is true even if you explicitly include the original Extension into Module with Module.send(:include, Extension). How do you add macro like methods to Ruby modules?

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  • How does the stream manipulators work?

    - by Narek
    It is well known that the user can define stream manipulators like this: ostream& tab(ostream & output) { return output<< '\t'; } And this can be used in main() like this: cout<<'a'<<tab<<'b'<<'c'<<endl; Please explain me how does this all work? If operator<< assumes as a second parameter a pointer to the function that takes and returns ostream &, then please explain my why it is necessary? What would be wrong if the function does not take and return ostream & but it was void instead of ostream &? Also it is interesting why “dec”, “hex” manipulators take effect until I don’t change between them, but user defined manipulators should be always used in order to take effect for each streaming?

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  • Ruby on Rails: Modules vs. Classes

    - by Jack
    I'm trying to add a function that will be accessible throughout all parts of my program. I want something like: def GlobalFunctions.my_function(x,y) puts x + y end to be accessible for all models. Specifically I am trying to use a function like this in my seeds.rb file but I am most likely going to be reusing the code and don't want any redundancy. Now I know I can make a simple class, but I could also make a module. What are some reasons to go in either direction? And once I've decided on which type to use, how do I make it accessible throughout the whole program? I have tried a module, but I keep getting " Expected app/[module file] to define [ModuleName]"

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  • Building a custom iterator.

    - by Isai
    I am making this class which is a custom Map based off a hash map. I have an add method where if you add an object the object will be the key, and its value will be 1 if the object is not currently in the list. However if you add object that is currently in the list its value will be bumped up by 1. So if I added 10 strings which were all the same, the key would be that string and the value will be 10. I understand in practice when I iterate through the map, there is actually only one object to iterate, however, I am trying to create a inner class that will define an iterator that will iterate the same object however many times its value is. I can do this by simply using for loops to construct an appropriate ArrayList and just create an iterator for that, but that is too inefficient. Is there an easy or more efficient way of doing this?

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  • Passing a String from PHP to a JavaScript function

    - by user635614
    Hello. am trying to write a code to pass a php string when clicked on the table : <?php . . . echo("<td onclick = 'print_("$file[$i]->Name");' >". $files[$i]->Name."</td>"); ... ?> where files[] is an array, and each element is a class with Name as a String, and it is put in a ''for'' loop, Am trying to pass it to a JavaScript function where i need the name there,and it's not working,i tried passing the i variable and it was passed correctly so i thought there should be a special syntax for dealing with strings... function print_(var x) { alert(x);}

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  • insert into table where if not in list

    - by jim smith
    Can anybody help me with the syntax? insert into history (company,partnumber,price) values ('blah','IFS0090','0.00') if company NOT IN ('blah','blah2','blah3','blah4','blah4') and partnumber='IFS0090'; Background: I have a history table which stores daily company, products and prices. But sometimes a company will remove itself for a few days. Complicating the issue is because I'm only saving daily CHANGES to prices only and not snapshotting the entire days list (the data would be huge) when I display the data the company will still come up for the previous days price. So I need to do something like this, where a 0.00 price means they're no longer there.

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  • Fast comparison of char arrays?

    - by StackedCrooked
    I'm currently working in a codebase where IPv4 addresses are represented as pointers to u_int8. The equality operator is implemented like this: bool Ipv4Address::operator==(const u_int8 * inAddress) const { return (*(u_int32*) this->myBytes == *(u_int32*) inAddress); } This is probably the fasted solution, but it causes the GCC compiler warning: ipv4address.cpp:65: warning: dereferencing type-punned pointer will break strict-aliasing rules How can I rewrite the comparison correctly without breaking strict-aliasing rules and without losing performance points? I have considered using either memcmp or this macro: #define IS_EQUAL(a, b) \ (a[0] == b[0] && a[1] == b[1] && a[2] == b[2] && a[3] == b[3]) I'm thinking that the macro is the fastest solution. What do you recommend?

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  • In C#: How to declare a generic Dictionary whose key and value types have a common constraint type?

    - by Marcel
    Hi all, I want to declare a dictionary that stores typed IEnumerable's of a specific type, with that exact type as key, like so: private IDictionary<T, IEnumerable<T>> _dataOfType where T: BaseClass; //does not compile! The concrete classes I want to store, all derive from BaseClass, therefore the idea to use it as constraint. The compiler complains that it expects a semicolon after the member name. If it would work, I would expect this would make the later retrieval from the dictionary simple like: IEnumerable<ConcreteData> concreteData; _sitesOfType.TryGetValue(typeof(ConcreteType), out concreteData); How to define such a dictionary?

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  • Perform function on form submit

    - by flight643
    Hopefully this is a pretty simple question! I've got the code working in jQuery to listen for a specific form on a page to be submitted and perform an alert when it is.. I.e.: The form itself doesn't have a name so I am targetting the form within a specific form ID. $("#content form").submit(function() { alert("lorem ipsum dolor?"); }); What would be the syntax for performing this in javascript alone without using jquery? For example, I have this code (below) and just am unsure of how to listen for the form to be submitted to perform an action.. var submitform = document.getElementById("content").getElementsByTagName("form"); Thanks!

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  • Local variable not being passed to partial template by render?

    - by brad
    I don't seem to be able to pass a variable to my partial template in rails (2.3.5). My code is as follows; In the main view .html.erb file: <% f.fields_for :payments do |payment_form| %> <%= render 'payment', {:f => payment_form, :t => "test" } %> <% end %> and in the _payment.html.erb file: <%= t %> produces a wrong number of arguments (0 for 1) error. The payment_form object is being passed to the partial as f without any problems. I've tried a number of variations on the above syntax (e.g. :locals => {:f => payment_form, :t => "test" } without success. I presume I'm doing something pretty basic wrong but just can't see it.

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  • How To Securly Store Data In MySQL Using AES_ENCRYPT

    - by Justin
    We are storing sensitive data in MySQL, and I want to use AES_ENCRYPT(data, 'my-secret-key-here') which works great. My biggest question is how do I secure the key? Previously I just wast storing the key in a web PHP file, so something like: define("ENCRYPTION_KEY", 'my-secret-key-here'); This really doesn't work though, as our MySQL server and web server are the same physical machine, so if somebody gains access to the server, they can get both the encrypted data stored in MySQL and the key. Any ideas? I am thinking I need to move the key to a separate server, and read it in remotely. Or, what about generating the encryption key dynamically for each piece of data. For example taking the customer_id and running md5 on it, and then using that as the key.

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  • [Perl] Use a Module / Object which is defined in the same file

    - by Robert S. Barnes
    I need to define some modules and use them all in the same file. No, I can't change the requirement. I would like to do something like the following: { package FooObj; sub new { ... } sub add_data { ... } } { package BarObj; use FooObj; sub new { ... # BarObj "has a" FooObj my $self = ( myFoo => FooObj->new() ); ... } sub some_method { ... } } my $bar = BarObj->new(); However, this results in the message: Can't locate FooObj.pm in @INC ... BEGIN failed... How do I get this to work?

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  • Why is the GUID structure declared the way it is?

    - by alabamasucks
    In rpc.h, the GUID structure is declared as follows: typedef struct _GUID { DWORD Data1; WORD Data2; WORD Data3; BYTE Data[8]; } GUID; I understand Data1, Data2, and Data3. They define the first, second, and third sets of hex digits when writing out a GUID (XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXX). What I never understood was why the last 2 groups were declared together in the same byte array. Wouldn't this have made more sense (and been easier to code against)? typedef struct _GUID { DWORD Data1; WORD Data2; WORD Data3; WORD Data4; BYTE Data5[6]; } GUID; Anyone know why it is declared this way?

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  • Circle class in java

    - by user292395
    I need to get the Java code for the below problem asap. Create a class Circle that will allow us to define a circle with a specific radius. Your class should include the following methods: A constructor that can create a circle with a specified radius. A method setRadius that sets a specific value as a new radius for an existing circle. A method getRadius that returns the radius of an existing circle. A method toString that returns a String with all the information about an existing circle. A method computeArea that computes the area of a circle A method computePerimeter that computes the perimeter of a circle.

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  • Tutorials for an experienced C# user to learn C++

    - by Tim R.
    Are there any good resources for learning C++ that a C# user could use, which don't require knowledge of C? I have quite a good knowledge of C# via courses in my University's game development program (in a 300 level course right now) but now I need to use C++ for a project. I would use a beginner tutorial but they are so hard for me to follow and learn the basic syntax because they start so slowly. I found a few of tutorials for switching from C++ to C#, but none in the other direction. I do have a little bit of Objective C practice from iPhone programming as well.

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  • Beginner Access VBA SQL INSERT Question

    - by Josh K
    Syntax question: I am using the code below to call a query in Access VBA strSQL = "INSERT INTO tblLoanDetails ([ServerName]) VALUES ('Test') WHERE [ID]=3" Call CurrentDb.Execute(strSQL) And i am getting a runtime error of "3067: Query must contain atleast one table or query." the insert statement string looks like this (Threw the var into a text box): INSERT INTO tblLoanDetails ([ServerName]) VALUES ('Test') WHERE [ID]=3 I also tried adding a semi-colon to the end but with no luck. I also double checked to make sure my table is called tblLoanDetails and my Column names are ServerName, and ID Appreciate any help.

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  • IPhone: Controllers, Delagates, DataSources, etc all in one class?

    - by MLS
    Hi All, I am learning iPhone programming. I am starting with a simple example of displaying recently used documents in a UITableView. What I am confused about is why do I need to have several classes and why cant I just use one? Example, My class is called RecentFileList. I need to implement controller, delegate and datasource as well as the actual table view. Can't I just do this all in my RecentFileList Class versus having to create a RecentFileListDelegate RecentFileListController, RecentFileListDataSource class, etc, etc. Related to this can one define a class like: @interface FileListView : NSObject <UITableViewDelegate> <UITableViewController> <UITableViewDataSource { // code } @end or would I just do the work to make my class a delegate and controller in init()?

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  • Using xval with fields containing periods

    - by JP
    Hello, I have been using xVal with success for a while but this evening ran into an issue where a field containing a period would not be validated (client or server-side). I am using ASP.NET MVC2 and need to use the period syntax in cases where I am model binding to a list. In the below example I am using a textbox for the sake of simplicity: xVal.AttachValidator(null, { "Fields": [{ "FieldName": "entry[622592].Value", "FieldRules": [{ "RuleName": "Required", "RuleParameters": {}}]}] }, {}) <input type="text" class="text" name="entry[622592].Value"/> If I replace both instances of "entry[622592].Value" to something trivial like "test" then the validation works successfully, but if i leave it this way the validation never appears to fire... Has anyone run into this issue? Thanks in advance!

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  • How to save an order (permutation) in an sql db

    - by Bendlas
    I have a tree structure in an sql table like so: CREATE TABLE containers ( container_id serial NOT NULL PRIMARY KEY, parent integer REFERENCES containers (container_id)) Now i want to define an ordering between nodes with the same parent. I Have thought of adding a node_index column, to ORDER BY, but that seem suboptimal, since that involves modifying the index of a lot of nodes when modifying the stucture. That could include adding, removing, reordering or moving nodes from some subtree to another. Is there a sql datatype for an ordered sequence, or an efficient way to emulate one? Doesn't need to be fully standard sql, I just need a solution for mssql and hopefully postgresql EDIT To make it clear, the ordering is arbitrary. Actually, the user will be able to drag'n'drop tree nodes in the GUI

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  • Rails - using :include to find objects based on their child's attributes

    - by adam
    I have a sentence and correction model class Sentence < ActiveRecord::Base has_one :correction class Correction < ActiveRecord::Base belongs_to :sentence and I'm trying find all sentences which don't have a correction. To do this I'm simply looking for corrections which don't exist i.e. whose id = nil. But it is failing and i can't figure out why Sentence.find :all, :include => :correction, :conditions => {:correction => {:id => nil}} Perhaps its the syntax or maybe just the overall approach. Can anyone help?

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  • mod_rewrite rule for all urls except ones with some words

    - by zlog
    How do I write a mod_rewrite regulare expression rule that is the opposite of this: ^(.+)/path/(page1|page2)+$ ie, I want all pages except blah/path/page1 and blah/path/page2 to redirect to another path, where the x in blah/path/x is used in the new path. For example, I'd like write a rewrite rule like: RewriteRule some_regex /index.php?path/show/$1 [L] where some_regex would pull out the last component of a url in the format: /something/path/some_param to redirect to /index.php/path/show/some_param I'm trying to use ! and [^] syntax, but I don't quite understand how these work, especially when they involve words not single characters.

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