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  • Need help with displaying the message correctly in the pole display always starting at the beginning

    - by SA
    Hi, I am using an HP RS232 pole display with the following setting: Char type: USA/Europe (default) Command mode: EPSON (default) Baud rate: 9600, n , 8, 1 (default?) Passthru None (Default) Here's the code using System.IO.Ports; private SerialPort port; port = new SerialPort("COM2", 9600, Parity.None, 8, StopBits.One); port.Handshake = Handshake.None; Port.WriteLine("Welocome to something something"); It has 2 lines consisting of 20 characters each with a total of 40 characters. I have no control how and where the characters get displayed. I would like it to always begin on line 1 position 1 but as I said earlier how would I be able to do that. The same program if I run again and again it moves a character to the left. I have set it to accept ASCII char set and so I am able to type as is visble in the Writeline message

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  • Get other classes from an element with Jquery

    - by Jigs
    I am working on a small bit of script that will allow for easy and flexible creation of buttons. My buttons are made of three parts, a left, a right and a streched middle piece. There are three different sizes and three different colours of each. I have written the code that resizes the button to fit the text. Now I am looking to add the ability to easily set the colour and size. I was thinking of using three classes something like <div class="button blue big"> My script already loops through the button classes using each. Now I need to find out what other classes are set and adjust the pictures and dimentions used to fit. So how can I find out what other class selectors an element has? Also I am fairly new to jquery/javascript so I am wondering if storing the design as class selectors is the best way.

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  • Inheritance: possible to change base reference to something else?

    - by fred
    For example I have two classes, Base and Derived as shown below: class Base { public string Name { get; set; } public Base() { } } class Derived : Base { public Derived(Base b) { base = b; // doesn't compile, but is there any way to do something similar? } } So that they behave like this: Base b = new Base(); b.Name = "Bob"; Derived d = new Derived(b); d.Name = "John"; // b.Name is now "John" also Is this possible? I guess one way would be to keep the Base b reference in Derived and override Derived.Name to point to b.Name? Is there an easier way though, for example if I have like 50 properties to override? class Derived : Base { Base b; public override string Name { get { return b.Name; } set { b.Name = value; } } public Derived(Base b) { this.b = b; } }

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  • mysqli::query returns true on SELECT statement

    - by Travis Pessetto
    I have an application that reads in one of its classes: public function __construct() { global $config; //Establish a connection to the database and get results set $this->db = new Database("localhost",$config["dbuser"],$config["dbpass"],"student"); $this->records = $this->db->query("SELECT * FROM major") or die("ERROR: ".$this->db->error); echo "<pre>".var_dump($this->records)."</pre>"; } My problem is that var_dump shows that $this->records is a boolean. I've read the documentation and see that the SELECT query should return a result set. This is the only query used by the application. Any ideas where I am going wrong?

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  • JS - Dynamic div content, but need a fixed div height.

    - by Joey Morani
    Hello. I'm using javascript to animate a div collapsing/sliding. The javascript requires the div to have a set height, although the content inside the div is dynamic. How would I go about making it work, as I don't want the div to be any larger than it's meant to. I've set the height of the div like this: <div id="main-div" style="overflow:hidden; height:95px;"> I've tried setting the height to 'auto' but when the div slides open again, it doesn't slide to the correct height. Would I need to calculate the height? Thanks.

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  • Get back the default browser styling for input fields

    - by meo
    I need to style all the input fields but one. So i have set a rule for all the inputs on the site. For the seachfield i need to use the browser default, so i was thinking i could just inherit all the values i have set for the general input fields. (have tried border: none to) This does not work in FF nor Safari :( The border just gets transparent. http://jsfiddle.net/N5KKH/1/ Any idea how i could get the default browser styling back? EDIT: i need the first input field look like the second one: http://jsfiddle.net/N5KKH/2/

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  • Can C# make my class look like another class?

    - by Vaccano
    I have a class that look like this: public class BasePadWI { public WorkItem WorkItemReference { get; set; } .... Other stuff ...... } I then have a dictionary that is defined like this: public Dictionary<BasePadWI, Canvas> Pad { get; set; } I would then like to make a call like this: List<WorkItem> workItems = Pad.Keys.ToList(); (Note: WorkItem is a sealed class, so I cannot inherit.) Is there some trickery that I could do in the class to make it look like a WorkItem? I have done this in the mean time: List<WorkItem> workItems = Pad.Keys.ToList().ConvertAll(x=>x.WorkItem);

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  • JavaScript: If clause partially executed !!!

    - by arwa
    Hi everyone My problem is that when the condition is true it will close the window but not execute the php part ! here goes my code.. function onClose() { var r=confirm("Is the meeting Over!"); if (r==true) { window.close(); } else { } } </blink> this is the php part.. $sql="UPDATE previousmeetings SET Live='0' WHERE MeetingID='34'"; //$meeting_id $sql2="UPDATE previousmeetings SET Live='1' WHERE MeetingID='34'";

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  • Does any method exist quickly to detect valid range versions of used library

    - by daneel-yaitskov
    I'm a beginner Haskell programmer. I have written some useful code for the last six month. And I want to release a library from it. The code will use system installation cabal as any Haskell library. A library is released with cabal has a meta data file where there is a logical predicate from the libraries and their versions. A developer usually uses one set libraries. It tediously care a set of the sets libraries. How to know either my library is compiled successfully or not for some subset libraries?

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  • How to access the backing field of a base class using fluent nhibernate?

    - by Akk
    How do i set the Access Strategy in the mapping class to point to the base _photos field? public class Content { private IList<Photo> _photos; public Content() { _photos = new List<Photo>(); } public virtual IEnumerable<Photo> Photos { get { return _photos; } } public virtual void AddPhoto() {...} } public class Article : Content { public string Body {get; set;} } I am currently using the following to try and locate the backing field but an exception is thrown as it cannot be found. public class ArticleMap : ClassMap<Article> { HasManyToMany(x => x.Photos) .Access.CamelCaseField(Prefix.Underscore) //_photos //... } i tried moving the backing field _photos directly into the class and the access works. So how can i access the backing field of the base class?

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  • Should a protected property in a C# child class hide access to a public property on the parent?

    - by Tim
    I have the following code: public class Parent { public string MyField { get; set; } } public class Child : Parent { protected new int MyField { get; set; } } I try and access this with: static void Main(string[] args) { Child child = new Child(); child.MyField = "something"; } Visual studio 2008 compiles this without comment, but under Mono (2.4.2, Ubuntu) I get the error message 'HideTest.Child.MyField' is inaccessible due to its protection level (CS0122) Is one implementation or the other more compliant with the standard here?

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  • ASP.Net Problem with View Control

    - by tking
    I admit, I'm an .NET n00b. Basically what I'm trying to do is I have a page with a text box on it and an image button. On click of the image button I want it to show a view control I have set up. Inside this view control is an image and some text. So this is what I have in my code-behind. protected void btnSubmit_Click(object sender, ImageClickEventArgs e) { string email = txtUnsubscribe.Text; vwSuccess.Visible = true; } Simple right? Well when I click on the button for submit, I get the "Object reference not set to an instance of an object." error message. Where am I going wrong?

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  • sifr menu list problems, height of object calculated wrong

    - by armyofda12mnkeys
    I am using Drupal and have sifr set on list items, and also a, a:hover are set via Drupal so that the links hover. I looked at the sifr3-rules.js file drupal's render module creates and it looks good. and in fact my other sifr items look fine... But the list item ones are goofing for some reason... There is extra space below the list, so if i have a list item, and inside of that, I have a unordered list with more list items, the Flash Object made in the 1st li (which will cover the rest of the sublist items too), is too bid so you see space under the children until the next parent li comes up. (so looks like extra bottom padding on that portion of the list in IE8... in FF almost similar but each subitem has space at bottom... with javascript turned off, you see the list items look fine by themselves).... Also if the parent list item is shorter than the sub list items text, the width for the flash object is set only as long as the first list item, and therefore cuts off the rest the sublist item's text. Any idea how to resolve any of these? Only unusual thing i see i am doing is setting forceSingleLine and preventWrap (which dont make a difference if taken off). ****Edit, I may just try to figure out how to get Drupal's menu-block module to output a around my hyperlinks in the list items... then i can target the div's with my rule (and the a,a:hover rules will apply), so each menu item gets its own sifr object instead of sifr3 trying to figure out how to do the lists and sublists. Very useful to me is anyone knows a way to target a hyperlink (<a> tag) and also allow a:hover rules. I know how to do it with pretend another tag that includes hyperlinks, like if i had <h2><a>sometitle</a></h2>, i could have a rule for h2, but then use the a, a:hover rules in the sifr3-rules.js file to target that. so i would need a way to target the hyperlink in the list, but also apply a :hover to it (not sure if this can be done since its not underneith for example the h2 tag).

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  • Remove class when move to next menu item

    - by danit
    I have a simple nav made up of the following HTML; <div class="inner"> <div class="button"><img class="portal" src="images/portalbutton.png" /></div> <a href="#"><div class="prod_description">&nbsp;</div></a> </div> There are a number of items (All set to float left along side each other) to make up a nav bar. When I hover over .button and/or .prod_description I want the .inner <div> to have the class .hover added to it. This is so I can set a background image around the whole thing (Kind of like highlighting the nav item). I only then want to remove .hover when another .button or .prod_description is hovered over, in which case this nav item takes the .hover class.

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  • mysql reference result from subquery

    - by iamrohitbanga
    this is what i am doing update t1 set x=a,y=b where a and b are obtained from (select query here) i know the select query the select query returns multiple results which are the same when i use group by or distinct query execution slows down considerably a and b are forward references so mysql reports an error i want to set a equal to the value obtained in the first row and b equal to the value obtained in the first row for the respective columns, to avoid group by. i don't know how to refer to the first result from the select query. how can i achieve all this?

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  • WFP Validation & IDataErrorInfo

    - by Jefim
    A note - the classes I have are EntityObject classes! I have the following class: public class Foo { public Bar Bar { get; set; } } public class Bar : IDataErrorInfo { public string Name { get; set; } #region IDataErrorInfo Members string IDataErrorInfo.Error { get { return null; } } string IDataErrorInfo.this[string columnName] { get { if (columnName == "Name") { return "Hello error!"; } Console.WriteLine("Validate: " + columnName); return null; } } #endregion } XAML goes as follows: <StackPanel Orientation="Horizontal" DataContext="{Binding Foo.Bar}"> <TextBox Text="{Binding Path=Name, ValidatesOnDataErrors=true}"/> </StackPanel> I put a breakpoint and a Console.Writeline on the validation there - I get no breaks. The validation is not executed. Can anybody just press me against the place where my error lies?

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  • how to pass user created connection to hibernate

    - by Mrityunjay
    hi, is there any way, to restrict hibernate not to create connection of its own(what we define in hibernate.properties or hibernate.cfg.xml), instead i can create and pass the connection to hibernate for further processing. The problem is that i need to set the ApplicationContext on the connection given that the i am using oracle connection. I know how to create a connection and set the applicationContext on to it.. but the problem is that i don't know how to force hibernate to use the connection that i have created.. Please help..

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  • Could/Should I use static classes in asp.net/c# for shared data?

    - by death.au
    Here's the situation I have: I'm building an online system to be used by school groups. Only one school can log into the system at any one time, and from that school you'll get about 13 users. They then proceed into a educational application in which they have to co-operate to complete tasks, and from a code point of view, sharing variables all over the place. I was thinking, if I set up a static class with static properties that hold the variables that are required to be shared, this could save me having to store/access the variables in/from a database, as long as the static variables are all properly initialized when the application starts and cleaned up at the end. Of course I would also have to put locks on the get and set methods to make the variables thread safe. Something in the back of my mind is telling me this might be a terrible way of going about things, but I'm not sure exactly why, so if people could give me their thoughts for or against using a static class in this situation, I would be quite appreciative.

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  • Do superfluous calls to addEventListenter("event", thisSpecificFunction) waste resources?

    - by Richard Haven
    I have ItemRenderers that need to listen for events. When they hear an event (and when data changes), they dispatch an event with their current data value. As item renderers are reused, each of them is going to add its callback in set data(value...)and pass the callback function in the event as well as the current data value. So, the listener of the item renderer's bubbling event will set someEventDispatcher.addEventListener("someEvent", itemRendererEvent.callbackListener). This will happen more than once. Does setting the same event listener on the same event for the same dispatcher waste resources? Does the displatcher see that it already has the listener?

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  • Delphi: EInvalidOp in neural network class (TD-lambda)

    - by user89818
    I have the following draft for a neural network class. This neural network should learn with TD-lambda. It is started by calling the getRating() function. But unfortunately, there is an EInvalidOp (invalid floading point operation) error after about 1000 iterations in the following lines: neuronsHidden[j] := neuronsHidden[j]+neuronsInput[t][i]*weightsInput[i][j]; // input -> hidden weightsHidden[j][k] := weightsHidden[j][k]+LEARNING_RATE_HIDDEN*tdError[k]*eligibilityTraceOutput[j][k]; // adjust hidden->output weights according to TD-lambda Why is this error? I can't find the mistake in my code :( Can you help me? Thank you very much in advance! unit uNeuronalesNetz; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, ExtCtrls, StdCtrls, Grids, Menus, Math; const NEURONS_INPUT = 43; // number of neurons in the input layer NEURONS_HIDDEN = 60; // number of neurons in the hidden layer NEURONS_OUTPUT = 1; // number of neurons in the output layer NEURONS_TOTAL = NEURONS_INPUT+NEURONS_HIDDEN+NEURONS_OUTPUT; // total number of neurons in the network MAX_TIMESTEPS = 42; // maximum number of timesteps possible (after 42 moves: board is full) LEARNING_RATE_INPUT = 0.25; // in ideal case: decrease gradually in course of training LEARNING_RATE_HIDDEN = 0.15; // in ideal case: decrease gradually in course of training GAMMA = 0.9; LAMBDA = 0.7; // decay parameter for eligibility traces type TFeatureVector = Array[1..43] of SmallInt; // definition of the array type TFeatureVector TArtificialNeuralNetwork = class // definition of the class TArtificialNeuralNetwork private // GENERAL SETTINGS START learningMode: Boolean; // does the network learn and change its weights? // GENERAL SETTINGS END // NETWORK CONFIGURATION START neuronsInput: Array[1..MAX_TIMESTEPS] of Array[1..NEURONS_INPUT] of Extended; // array of all input neurons (their values) for every timestep neuronsHidden: Array[1..NEURONS_HIDDEN] of Extended; // array of all hidden neurons (their values) neuronsOutput: Array[1..NEURONS_OUTPUT] of Extended; // array of output neurons (their values) weightsInput: Array[1..NEURONS_INPUT] of Array[1..NEURONS_HIDDEN] of Extended; // array of weights: input->hidden weightsHidden: Array[1..NEURONS_HIDDEN] of Array[1..NEURONS_OUTPUT] of Extended; // array of weights: hidden->output // NETWORK CONFIGURATION END // LEARNING SETTINGS START outputBefore: Array[1..NEURONS_OUTPUT] of Extended; // the network's output value in the last timestep (the one before) eligibilityTraceHidden: Array[1..NEURONS_INPUT] of Array[1..NEURONS_HIDDEN] of Array[1..NEURONS_OUTPUT] of Extended; // array of eligibility traces: hidden layer eligibilityTraceOutput: Array[1..NEURONS_TOTAL] of Array[1..NEURONS_TOTAL] of Extended; // array of eligibility traces: output layer reward: Array[1..MAX_TIMESTEPS] of Array[1..NEURONS_OUTPUT] of Extended; // the reward value for all output neurons in every timestep tdError: Array[1..NEURONS_OUTPUT] of Extended; // the network's error value for every single output neuron t: Byte; // current timestep cyclesTrained: Integer; // number of cycles trained so far (learning rates could be decreased accordingly) last50errors: Array[1..50] of Extended; // LEARNING SETTINGS END public constructor Create; // create the network object and do the initialization procedure UpdateEligibilityTraces; // update the eligibility traces for the hidden and output layer procedure tdLearning; // learning algorithm: adjust the network's weights procedure ForwardPropagation; // propagate the input values through the network to the output layer function getRating(state: TFeatureVector; explorative: Boolean): Extended; // get the rating for a given state (feature vector) function HyperbolicTangent(x: Extended): Extended; // calculate the hyperbolic tangent [-1;1] procedure StartNewCycle; // start a new cycle with everything set to default except for the weights procedure setLearningMode(activated: Boolean=TRUE); // switch the learning mode on/off procedure setInputs(state: TFeatureVector); // transfer the given feature vector to the input layer (set input neurons' values) procedure setReward(currentReward: SmallInt); // set the reward for the current timestep (with learning then or without) procedure nextTimeStep; // increase timestep t function getCyclesTrained(): Integer; // get the number of cycles trained so far procedure Visualize(imgHidden: Pointer); // visualize the neural network's hidden layer end; implementation procedure TArtificialNeuralNetwork.UpdateEligibilityTraces; var i, j, k: Integer; begin // how worthy is a weight to be adjusted? for j := 1 to NEURONS_HIDDEN do begin for k := 1 to NEURONS_OUTPUT do begin eligibilityTraceOutput[j][k] := LAMBDA*eligibilityTraceOutput[j][k]+(neuronsOutput[k]*(1-neuronsOutput[k]))*neuronsHidden[j]; for i := 1 to NEURONS_INPUT do begin eligibilityTraceHidden[i][j][k] := LAMBDA*eligibilityTraceHidden[i][j][k]+(neuronsOutput[k]*(1-neuronsOutput[k]))*weightsHidden[j][k]*neuronsHidden[j]*(1-neuronsHidden[j])*neuronsInput[t][i]; end; end; end; end; procedure TArtificialNeuralNetwork.setReward; VAR i: Integer; begin for i := 1 to NEURONS_OUTPUT do begin // +1 = player A wins // 0 = draw // -1 = player B wins reward[t][i] := currentReward; end; end; procedure TArtificialNeuralNetwork.tdLearning; var i, j, k: Integer; begin if learningMode then begin for k := 1 to NEURONS_OUTPUT do begin if reward[t][k] = 0 then begin tdError[k] := GAMMA*neuronsOutput[k]-outputBefore[k]; // network's error value when reward is 0 end else begin tdError[k] := reward[t][k]-outputBefore[k]; // network's error value in the final state (reward received) end; for j := 1 to NEURONS_HIDDEN do begin weightsHidden[j][k] := weightsHidden[j][k]+LEARNING_RATE_HIDDEN*tdError[k]*eligibilityTraceOutput[j][k]; // adjust hidden->output weights according to TD-lambda for i := 1 to NEURONS_INPUT do begin weightsInput[i][j] := weightsInput[i][j]+LEARNING_RATE_INPUT*tdError[k]*eligibilityTraceHidden[i][j][k]; // adjust input->hidden weights according to TD-lambda end; end; end; end; end; procedure TArtificialNeuralNetwork.ForwardPropagation; var i, j, k: Integer; begin for j := 1 to NEURONS_HIDDEN do begin neuronsHidden[j] := 0; for i := 1 to NEURONS_INPUT do begin neuronsHidden[j] := neuronsHidden[j]+neuronsInput[t][i]*weightsInput[i][j]; // input -> hidden end; neuronsHidden[j] := HyperbolicTangent(neuronsHidden[j]); // activation of hidden neuron j end; for k := 1 to NEURONS_OUTPUT do begin neuronsOutput[k] := 0; for j := 1 to NEURONS_HIDDEN do begin neuronsOutput[k] := neuronsOutput[k]+neuronsHidden[j]*weightsHidden[j][k]; // hidden -> output end; neuronsOutput[k] := HyperbolicTangent(neuronsOutput[k]); // activation of output neuron k end; end; procedure TArtificialNeuralNetwork.setLearningMode; begin learningMode := activated; end; constructor TArtificialNeuralNetwork.Create; var i, j, k: Integer; begin inherited Create; Randomize; // initialize random numbers generator learningMode := TRUE; cyclesTrained := -2; // only set to -2 because it will be increased twice in the beginning StartNewCycle; for j := 1 to NEURONS_HIDDEN do begin for k := 1 to NEURONS_OUTPUT do begin weightsHidden[j][k] := abs(Random-0.5); // initialize weights: 0 <= random < 0.5 end; for i := 1 to NEURONS_INPUT do begin weightsInput[i][j] := abs(Random-0.5); // initialize weights: 0 <= random < 0.5 end; end; for i := 1 to 50 do begin last50errors[i] := 0; end; end; procedure TArtificialNeuralNetwork.nextTimeStep; begin t := t+1; end; procedure TArtificialNeuralNetwork.StartNewCycle; var i, j, k, m: Integer; begin t := 1; // start in timestep 1 cyclesTrained := cyclesTrained+1; // increase the number of cycles trained so far for j := 1 to NEURONS_HIDDEN do begin neuronsHidden[j] := 0; for k := 1 to NEURONS_OUTPUT do begin eligibilityTraceOutput[j][k] := 0; outputBefore[k] := 0; neuronsOutput[k] := 0; for m := 1 to MAX_TIMESTEPS do begin reward[m][k] := 0; end; end; for i := 1 to NEURONS_INPUT do begin for k := 1 to NEURONS_OUTPUT do begin eligibilityTraceHidden[i][j][k] := 0; end; end; end; end; function TArtificialNeuralNetwork.getCyclesTrained; begin result := cyclesTrained; end; procedure TArtificialNeuralNetwork.setInputs; var k: Integer; begin for k := 1 to NEURONS_INPUT do begin neuronsInput[t][k] := state[k]; end; end; function TArtificialNeuralNetwork.getRating; begin setInputs(state); ForwardPropagation; result := neuronsOutput[1]; if not explorative then begin tdLearning; // adjust the weights according to TD-lambda ForwardPropagation; // calculate the network's output again outputBefore[1] := neuronsOutput[1]; // set outputBefore which will then be used in the next timestep UpdateEligibilityTraces; // update the eligibility traces for the next timestep nextTimeStep; // go to the next timestep end; end; function TArtificialNeuralNetwork.HyperbolicTangent; begin if x > 5500 then // prevent overflow result := 1 else result := (Exp(2*x)-1)/(Exp(2*x)+1); end; end.

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  • Interface issue

    - by peter
    i added a property 'WrmVersion' in interface IResourcePolicy but i am not getting those thing in the implementation side means here it should come in the List view data. means SubItems.Add(((IResourcePolicy)Data).WrmVersion is not getting This is the interface public interface IResourcePolicy { DataVersion WrmVersion { get; set; } bool ResourcePolicyEnabled { get; set; } } i am implementing it in public new IResourcePolicy Data { get { return (IResourcePolicy)base.Data; } } protected override void OnUpdate() { if(Data != null) { Text = base.Data.Name; if(SubItems.Count == 1) { SubItems.Add(((IResourcePolicy)Data).ResourcePolicyEnabled.ToString()); }

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  • Default datetime format in mySQL

    - by Davuz
    I'm coding to search data by compare datetime. In web form, user input value '2012-06-04' store in $_REQUEST['dateSearch']. I create datetime object from that: $dateObj = date_create_from_format("Y-m-d",$_REQUEST['dateSearch']); $dateParam = $dateObj->format("Y-m"); Then I use $dateParam in sql query to find data $sql = " SELECT * FROM `temp` as `t` WHERE `t`.`date` LIKE '$dateParam%' "; Everything is ok, but I'm not sure mySQL alway use only one datetime format "Y-m-d H:i:s". At here, $dateParam = $dateObj->format("Y-m"); I set default format is "Y-m". Is the default format never change? I don't want hard set format "Y-m-d H:i:s" in code, instead of, I think get format string from system to use is better. How do I get default datetime format string from mySQL???

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  • Co-opt popular abandonware opensource project?

    - by Mike Bouck
    Here's the scenario: A popular open source project is used/loved by many but has become stale due to the fact that the last drop came out nearly a year ago. Many bugs/feature requests/fixes have been logged in the interim and everyone is getting by via downloading the trunk and building custom/private builds with the changes incorporated. The copyright is simple -- there is none and the code is in the public domain. The project owner spins the project as community open source and has set up a sourceforge site, but to date (5 years running now) has yet to accept one contributor. In other words the "community" is a community of one. The project owner takes great pride in the project and has obviously contributed a lot of time/effort but for whatever reason has has seemingly abandoned the project and is unresponsive when offers of help are made. So, the question, should the community fork the codebase, set up a new community site, and take matters in their own hands?

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  • Is there a single query that can update a "sequence number" across multiple groups?

    - by Drarok
    Given a table like below, is there a single-query way to update the table from this: | id | type_id | created_at | sequence | |----|---------|------------|----------| | 1 | 1 | 2010-04-26 | NULL | | 2 | 1 | 2010-04-27 | NULL | | 3 | 2 | 2010-04-28 | NULL | | 4 | 3 | 2010-04-28 | NULL | To this (note that created_at is used for ordering, and sequence is "grouped" by type_id): | id | type_id | created_at | sequence | |----|---------|------------|----------| | 1 | 1 | 2010-04-26 | 1 | | 2 | 1 | 2010-04-27 | 2 | | 3 | 2 | 2010-04-28 | 1 | | 4 | 3 | 2010-04-28 | 1 | I've seen some code before that used an @ variable like the following, that I thought might work: SET @seq = 0; UPDATE `log` SET `sequence` = @seq := @seq + 1 ORDER BY `created_at`; But that obviously doesn't reset the sequence to 1 for each type_id. If there's no single-query way to do this, what's the most efficient way? Data in this table may be deleted, so I'm planning to run a stored procedure after the user is done editing to re-sequence the table.

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