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  • return only the last select results from stored procedure

    - by Madalina Dragomir
    The requirement says: stored procedure meant to search data, based on 5 identifiers. If there is an exact match return ONLY the exact match, if not but there is an exact match on the not null parameters return ONLY these results, otherwise return any match on any 4 not null parameters... and so on My (simplified) code looks like: create procedure xxxSearch @a nvarchar(80), @b nvarchar(80)... as begin select whatever from MyTable t where ((@a is null and t.a is null) or (@a = t.a)) and ((@b is null and t.b is null) or (@b = t.b))... if @@ROWCOUNT = 0 begin select whatever from MyTable t where ((@a is null) or (@a = t.a)) and ((@b is null) or (@b = t.b))... if @@ROWCOUNT = 0 begin ... end end end As a result there can be more sets of results selected, the first ones empty and I only need the last one. I know that it is easy to get the only the last result set on the application side, but all our stored procedure calls go through a framework that expects the significant results in the first table and I'm not eager to change it and test all the existing SPs. Is there a way to return only the last select results from a stored procedure? Is there a better way to do this task ?

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  • Moving to an arbitrary position in a file in Python

    - by B Rivera
    Let's say that I routinely have to work with files with an unknown, but large, number of lines. Each line contains a set of integers (space, comma, semicolon, or some non-numeric character is the delimiter) in the closed interval [0, R], where R can be arbitrarily large. The number of integers on each line can be variable. Often times I get the same number of integers on each line, but occasionally I have lines with unequal sets of numbers. Suppose I want to go to Nth line in the file and retrieve the Kth number on that line (and assume that the inputs N and K are valid --- that is, I am not worried about bad inputs). How do I go about doing this efficiently in Python 3.1.2 for Windows? I do not want to traverse the file line by line. I tried using mmap, but while poking around here on SO, I learned that that's probably not the best solution on a 32-bit build because of the 4GB limit. And in truth, I couldn't really figure out how to simply move N lines away from my current position. If I can at least just "jump" to the Nth line then I can use .split() and grab the Kth integer that way. The nuance here is that I don't just need to grab one line from the file. I will need to grab several lines: they are not necessarily all near each other, the order in which I get them matters, and the order is not always based on some deterministic function. Any ideas? I hope this is enough information. Thanks!

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  • WPF - How do I use the UserControl with a dependency property and view model?

    - by user320849
    Hello, My goal is to have a user select a year and a month. Translate the selection into a date and have the user control send the date back to my view model. That part works for me....However, I cannot get the ViewModel's initial date to set those drop downs. public static readonly DependencyProperty Date = DependencyProperty.Register("ReturnDate", typeof(DateTime), typeof(DatePicker), new FrameworkPropertyMetadata{BindsTwoWayByDefault = true,}); public DateTime ReturnDate { get { return Convert.ToDateTime(GetValue(Date)); } set { SetDropDowns(value); SetValue(Date, value); } } The SetDropDowns(value) just sets the selected items on the combo boxes, however, the program never makes it to that method. On the view I am using: <cc1:DatePicker ReturnDate="{Binding Path=StartDate, Mode=TwoWay}" IsStart="True" /> If this has been answered, then my bad. I looked around and didn't see anything that worked for me. Thus, when the program loads how do I get the value from the view model to a method in order to set the combo boxes? Thanks, -Scott

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  • How does DateTime.Now affect query plan caching in SQL Server?

    - by Bill Paetzke
    Question: Does passing DateTime.Now as a parameter to a proc prevent SQL Server from caching the query plan? If so, then is the web app missing out on huge performance gains? Possible Solution: I thought DateTime.Today.AddDays(1) would be a possible solution. It would pass the same end-date to the sql proc (per day). And the user would still get the latest data. Please speak to this as well. Given Example: Let's say we have a stored procedure. It reports data back to a user on a webpage. The user can set a date range. If the user sets today's date as the "end date," which includes today's data, the web app passes DateTime.Now to the sql proc. Let's say that one user runs a report--5/1/2010 to now--over and over several times. On the webpage, the user sees 5/1/2010 to 5/4/2010. But the web app passes DateTime.Now to the sql proc as the end date. So, the end date in the proc will always be different, although the user is querying a similar date range. Assume the number of records in the table and number of users are large. So any performance gains matter. Hence the importance of the question. Example proc and execution (if that helps to understand): CREATE PROCEDURE GetFooData @StartDate datetime @EndDate datetime AS SELECT * FROM Foo WHERE LogDate >= @StartDate AND LogDate < @EndDate Here's a sample execution using DateTime.Now: EXEC GetFooData '2010-05-01', '2010-05-04 15:41:27' -- passed in DateTime.Now Here's a sample execution using DateTime.Today.AddDays(1) EXEC GetFooData '2010-05-01', '2010-05-05' -- passed in DateTime.Today.AddDays(1) The same data is returned for both procs, since the current time is: 2010-05-04 15:41:27.

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  • How do I cast a void pointer to a struct in C?

    - by Rowhawn
    In a project I'm writing code for, I have a void pointer, "implementation", which is a member of a "Hash_map" struct, and points to an "Array_hash_map" struct. The concepts behind this project are not very realistic, but bear with me. The specifications of the project ask that I cast the void pointer "implementation" to an "Array_hash_map" before I can use it in any functions. My question, specifically is, what do I do in the functions to cast the void pointers to the desired struct? Is there one statement at the top of each function that casts them or do I make the cast every time I use "implementation"? Here are the typedefs the structs of a Hash_map and Array_hash_map as well as a couple functions making use of them. typedef struct { Key_compare_fn key_compare_fn; Key_delete_fn key_delete_fn; Data_compare_fn data_compare_fn; Data_delete_fn data_delete_fn; void *implementation; } Hash_map; typedef struct Array_hash_map{ struct Unit *array; int size; int capacity; } Array_hash_map; typedef struct Unit{ Key key; Data data; } Unit; functions: /* Sets the value parameter to the value associated with the key parameter in the Hash_map. */ int get(Hash_map *map, Key key, Data *value){ int i; if (map == NULL || value == NULL) return 0; for (i = 0; i < map->implementation->size; i++){ if (map->key_compare_fn(map->implementation->array[i].key, key) == 0){ *value = map->implementation->array[i].data; return 1; } } return 0; } /* Returns the number of values that can be stored in the Hash_map, since it is represented by an array. */ int current_capacity(Hash_map map){ return map.implementation->capacity; }

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  • Heavy Mysql operation & Time Constraints [closed]

    - by Rahul Jha
    There is a performance issue where that I have stuck with my application which is based on PHP & MySql. The application is for Data Migration where data has to be uploaded and after various processes (Cleaning from foreign characters, duplicate check, id generation) it has to be inserted into one central table and then to 5 different tables. There, an id is generated and that id has to be updated to central table. There are different sets of records and validation rules. The problem I am facing is that when I insert say(4K) rows file (containing 20 columns) it is working fine within 15 min it gets inserted everywhere. But, when I insert the same records again then at this time it is taking one hour to insert (ideally it should get inserted by marking earlier inserted data as duplicate). After going through the log file, I noticed is that there is a Mysql select statement where I am checking the duplicates and getting ID which are duplicates. Then I am calling a function inside for loop which is basically inserting records into 5 tables and updates id to central table. This Calling function is major time of whole process. P.S. The records has to be inserted record by record.. Kindly Suggest some solution.. //This is that sample code $query=mysql_query("SELECT DISTINCT p1.ID FROM table1 p1, table2 p2, table3 a WHERE p2.datatype =0 AND (p1.datatype =1 || p1.datatype=2) AND p2.ID =0 AND p1.ID = a.ID AND p1.coulmn1 = p2.column1 AND p1.coulmn2 = p2.coulmn2 AND a.coulmn3 = p2.column3"); $num=mysql_num_rows($query); for($i=0;$i<$num;$i++) { $f=mysql_result($query,$i,"ID"); //calling function RecordInsert($f); }

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  • How to change XmlSchemaElement.SchemaType (or: difference between SchemaType and ElementSchemaType)

    - by Gregor
    Hey, I'm working on a XML Editor which gets all his information from the corresponding XSD file. To work with the XSD files I use the System.Xml.Schema Namespace (XmlSchema*). Because of an 'xsi:type' attribute in the XML I've to change the XmlSchemaType of an XmlSchemaElement. Until now I use in my code the 'ElementSchemaType' property of 'XmlSchemaElement'. The nice thing about it: it's read only. There is also in 'XmlSchemaElement' an 'SchemaType' property which is not read only, but always null (yes, XmlSchema and XmlSchemaSet are compiled). So how can I change the type of the 'XmlSchemaElement'? Or, also the same question: What is the diffrence between this two porperties? Some technical data: C#, .NET 3.5 The MSDN documentation is nearly the same for both: SchemaType Documentation: Gets or sets the type of the element. This can either be a complex type or a simple type. ElementSchemaType Documentation: Gets an XmlSchemaType object representing the type of the element based on the SchemaType or SchemaTypeName values of the element.

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  • Aligning music notes using String matching algorithms or Dynamic Programming

    - by Dolphin
    Hi I need to compare 2 sets of musical pieces (i.e. a playing-taken in MIDI format-note details extracted and saved in a database table, against sheet music-taken into XML format). When evaluating playing against sheet music (i.e.note details-pitch, duration, rhythm), note alignment needs to be done - to identify missed/extra/incorrect/swapped notes that from the reference (sheet music) notes. I have like 1800-2500 notes in one piece approx (can even be more-with polyphonic, right now I'm doing for monophonic). So will I have to have all these into an array? Will it be memory overloading or stack overflow? There are string matching algorithms like KMP, Boyce-Moore. But note alignment can also be done through Dynamic Programming. How can I use Dynamic Programming to approach this? What are the available algorithms? Is it about approximate string matching? Which approach is much productive? String matching algos like Boyce-Moore, or dynamic programming? How can I assess which is more effective? Greatly appreciate any insight or suggestions Thanks in advance

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  • NetBeans Platform - how to refresh the property sheet view of a node?

    - by I82Much
    Hi all, I am using the PropertySheetView component to visualize and edit the properties of a node. This view should always reflect the most recent properties of the object; if there is a change to the object in another process, I want to somehow refresh the view and see the updated properties. The best way I was able to do this is something like the following (making use of EventBus library to publish and subscribe to changes in objects): public DomainObjectWrapperNode(DomainObject obj) { super (Children.LEAF, Lookups.singleton(obj)); EventBus.subscribe(DomainObject.class, this); } public void onEvent(DomainObject event) { // Do a check to determine if the updated object is the one wrapped by this node; // if so fire a property sets change firePropertySetsChange(null, this.getPropertySets()); } This works, but my place in the scrollpane is lost when the sheet refreshes; it resets the view to the top of the list and I have to scroll back down to where I was before the refresh action. So my question is, is there a better way to refresh the property sheet view of a node, specifically so my place in the property list is not lost upon refresh?

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  • What is an efficient strategy for multiple threads posting jobs and waiting for response from a single thread?

    - by jakewins
    In java, what is an efficient solution to the following problem: I have multiple threads (10-20 or so) generating jobs ("Job Creators"), and a single thread capable of performing them ("The worker"). Once a job creator has posted a job, it should wait for the job to finish, yielding no result other than "it's done", before it keeps going. For sending the jobs to the worker thread, I think a ring buffer or similar standard fan-in setup would perhaps be a good approach? But for a Job Creator to find out that her job has been done, I'm not so sure.. The job creators could sleep, and the worker interrupt them when done.. Or each job creator could have an atomic boolean that it checks, and that the worker sets. I dunno, neither of those feel very nice. I'd like to do it with as few (none, if possible) locks as absolutely possible. So to be clear: What I'm looking for is speed, not necessarily simplicity. Does anyone have any suggestions? Links to reading about concurrency strategies would also be very welcome!

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  • What is the process involved in viewing a webservice in a browser from within visual studio?

    - by Sam Holder
    I have created a new VS2008 ASP.Net Web service project, with the default name WebService1. If I right click on the Service1.asmx file and select 'View in Browser' what are the processes that go on to make this happen? I am asking because I have a situation where when I run this from a visual studio project started in our development shell (which sets up a common build environment) I cannot get the web service to show up in the browser. It starts the asp.net development server and creates a single file: C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\c43ddc22\268ae91b\hash\hash.web but when I start it from a stand alone project i get a whole slew of files in here: C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\edad4eee\d198cf0e\App_Web_defaultwsdlhelpgenerator.aspx.cdcab7d2.vicgkf94.dll C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\edad4eee\d198cf0e\service1.asmx.cdcab7d2.compiled etc etc I am trying to debug this but not really getting anywhere. i have inspected the output from VS but the only option I get is for the build output, which is basic and doesn't really contain any information that is useful. I have tried running both versions with DebugView running but no output there either. I would like to know if there are any log files I could look at, or if anyone has any suggestions on how I might be able to debug what is going wrong here? For completeness the output I get when it doesn't work is: Parser Error Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately. Parser Error Message: Could not create type 'WebService1.Service1'. Source Error: Line 1: Source File: /Service1.asmx Line: 1 Version Information: Microsoft .NET Framework Version:2.0.50727.3603; ASP.NET Version:2.0.50727.3082

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  • git changes modification time of files

    - by tanascius
    In the GitFaq I can read, that Git sets the current time as the timestamp on every file it modifies, but only those. However, I tried this command sequence (EDIT: added complete command sequence) $ git init test && cd test Initialized empty Git repository in d:/test/.git/ exxxxxxx@wxxxxxxx /d/test (master) $ touch filea fileb exxxxxxx@wxxxxxxx /d/test (master) $ git add . exxxxxxx@wxxxxxxx /d/test (master) $ git commit -m "first commit" [master (root-commit) fcaf171] first commit 0 files changed, 0 insertions(+), 0 deletions(-) create mode 100644 filea create mode 100644 fileb exxxxxxx@wxxxxxxx /d/test (master) $ ls -l > filea exxxxxxx@wxxxxxxx /d/test (master) $ touch fileb -t 200912301000 exxxxxxx@wxxxxxxx /d/test (master) $ ls -l total 1 -rw-r--r-- 1 exxxxxxx Administ 132 Feb 12 18:36 filea -rw-r--r-- 1 exxxxxxx Administ 0 Dec 30 10:00 fileb exxxxxxx@wxxxxxxx /d/test (master) $ git status -a warning: LF will be replaced by CRLF in filea # On branch master warning: LF will be replaced by CRLF in filea # Changes to be committed: # (use "git reset HEAD <file>..." to unstage) # # modified: filea # exxxxxxx@wxxxxxxx /d/test (master) $ git checkout . exxxxxxx@wxxxxxxx /d/test (master) $ ls -l total 0 -rw-r--r-- 1 exxxxxxx Administ 0 Feb 12 18:36 filea -rw-r--r-- 1 exxxxxxx Administ 0 Feb 12 18:36 fileb Now my question: Why did git change the timestamp of file fileb? I'd expect the timestamp to be unchanged. Are my commands causing a problem? Maybe it is possible to do something like a git checkout . --modified instead? I am using git version 1.6.5.1.1367.gcd48 under mingw32/windows xp.

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  • OSMF seek with Amazon Cloudfront

    - by giorrrgio
    I've written a little OSMF player that streams via RTMP from Amazon Cloudfront. There's a known issue, the mp3 duration is not correctly readed from metadata and thus the seek function is not working. I know there's a workaround implying the use of getStreamLength function of NetConnection, which I successfully implemented in a previous non-OSMF player, but now I don't know how and when to call it, in terms of OSMF Events and Traits. This code is not working: protected function initApp():void { //the pointer to the media var resource:URLResource = new URLResource( STREAMING_PATH ); // Create a mediafactory instance mediaFactory = new DefaultMediaFactory(); //creates and sets the MediaElement (generic) with a resource and path element = mediaFactory.createMediaElement( resource ); var loadTrait:NetStreamLoadTrait = element.getTrait(MediaTraitType.LOAD) as NetStreamLoadTrait; loadTrait.addEventListener(LoaderEvent.LOAD_STATE_CHANGE, _onLoaded); player = new MediaPlayer( element ); //Marker 5: Add MediaPlayer listeners for media size and current time change player.addEventListener( DisplayObjectEvent.MEDIA_SIZE_CHANGE, _onSizeChange ); player.addEventListener( TimeEvent.CURRENT_TIME_CHANGE, _onProgress ); initControlBar(); } private function onGetStreamLength(result:Object):void { Alert.show("The stream length is " + result + " seconds"); duration = Number(result); } private function _onLoaded(e:LoaderEvent):void { if (e.newState == LoadState.READY) { var loadTrait:NetStreamLoadTrait = player.media.getTrait(MediaTraitType.LOAD) as NetStreamLoadTrait; if (loadTrait && loadTrait.netStream) { var responder:Responder = new Responder(onGetStreamLength); loadTrait.connection.call("getStreamLength", responder, STREAMING_PATH); } } }

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  • Exporting de-aggregated data

    - by Ben
    I'm currently working on a data export feature for a survey application. We are using SQL2k8. We store data in a normalized format: QuestionId, RespondentId, Answer. We have a couple other tables that define what the question text is for the QuestionId and demographics for the RespondentId... Currently I'm using some dynamic SQL to generate a pivot that joins the question table to the answer table and creates an export, its working... The problem is that it seems slow and we don't have that much data (less than 50k respondents). Right now I'm thinking "why am I 'paying' to de-aggregate the data for each query? Why don't I cache that?" The data being exported is based on dynamic criteria. It could be "give me respondents that completed on x date (or range)" or "people that like blue", etc. Because of that, I think I have to cache at the respondent level, find out what respondents are being exported and then select their combined cached de-aggregated data. To me the quick and dirty fix is a totally flat table, RespondentId, Question1, Question2, etc. The problem is, we have multiple clients and that doesn't scale AND I don't want to have to maintain the flattened table as the survey changes. So I'm thinking about putting an XML column on the respondent table and caching the results of a SELECT * FROM Data FOR XML AUTO WHERE RespondentId = x. With that in place, I would then be able to get my export with filtering and XML calls into the XML column. What are you doing to export aggregated data in a flattened format (CSV, Excel, etc)? Does this approach seem ok? I worry about the cost of XML functions on larger result sets (think SELECT RespondentId, XmlCol.value('//data/question_1', 'nvarchar(50)') AS [Why is there air?], XmlCol.RinseAndRepeat)... Is there a better technology/approach for this? Thanks!

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  • implementing gravity to projectile - delta time issue

    - by Murat Nafiz
    I'm trying to implement a simple projectile motion in Android (with openGL). And I want to add gravity to my world to simulate a ball's dropping realistically. I simply update my renderer with a delta time which is calculated by: float deltaTime = (System.nanoTime()-startTime) / 1000000000.0f; startTime = System.nanoTime(); screen.update(deltaTime); In my screen.update(deltaTime) method: if (isballMoving) { golfBall.updateLocationAndVelocity(deltaTime); } And in golfBall.updateLocationAndVelocity(deltaTime) method: public final static double G = -9.81; double vz0 = getVZ0(); // Gets initial velocity(z) double z0 = getZ0(); // Gets initial height double time = getS(); // gets total time from act begin double vz = vz0 + G * deltaTime; // calculate new velocity(z) double z = z0 - vz0 * deltaTime- 0.5 * G * deltaTime* deltaTime; // calculate new position time = time + deltaTime; // Update time setS(time); //set new total time Now here is the problem; If I set deltaTime as 0.07 statically, then the animation runs normally. But since the update() method runs as faster as it can, the length and therefore the speed of the ball varies from device to device. If I don't touch deltaTime and run the program (deltaTime's are between 0.01 - 0.02 with my test devices) animation length and the speed of ball are same at different devices. But the animation is so SLOW! What am I doing wrong?

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  • Codeigniter: Library function--I'm stuck

    - by Kevin Brown
    I have a library function that sets up my forms, and submits data. They're long, and they work, so I'll spare you reading my code. :) I simply need a way for my functions to determine how to handle the data. Until now, the function did one thing: Submit a report for the current user. NOW, the client has requested that an administrator also be able to complete a form--this means that the form would be filled out, and it would CREATE a user at the same time, whereas the current function EDITS and is accessed by an EXISTING user. Do I need a separate function to do essentially the same thing? How do I make one function perform two tasks? One to update a user, and if there is no user, create one. Current controller: function survey() { $id = $this->session->userdata('id'); $data['member'] = $this->home_model->getUser($id); //Convert the db Object to a row array $data['manager'] = $data['member']->row(); $manager_id = $data['manager']->manager_id; $data['manager'] = $this->home_model->getUser($manager_id); $data['manager'] = $data['manager']->row(); $data['header'] = "Home"; $this->survey_form_processing->survey_form($this->_container,$data, $method); } Current Library: function survey_form($container) { //Lots of validation stuff $this->CI->validation->set_rules($rules); if ( $this->CI->validation->run() === FALSE ) { // Output any errors $this->CI->validation->output_errors(); } else { // Submit form $this->_submit(); } $this->CI->load->view($container,$data); The submit function is huge too. Basically says, "Update table with data where user_id=current user" I hope this wasn't too confusing. I'll create two functions if need be, but I'd like to keep redundancy down! }

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  • A C# Refactoring Question...

    - by james lewis
    I came accross the following code today and I didn't like it. It's fairly obvious what it's doing but I'll add a little explanation here anyway: Basically it reads all the settings for an app from the DB and the iterates through all of them looking for the DB Version and the APP Version then sets some variables to the values in the DB (to be used later). I looked at it and thought it was a bit ugly - I don't like switch statements and I hate things that carry on iterating through a list once they're finished. So I decided to refactor it. My question to all of you is how would you refactor it? Or do you think it even needs refactoring at all? Here's the code: using (var sqlConnection = new SqlConnection(Lfepa.Itrs.Framework.Configuration.ConnectionString)) { sqlConnection.Open(); var dataTable = new DataTable("Settings"); var selectCommand = new SqlCommand(Lfepa.Itrs.Data.Database.Commands.dbo.SettingsSelAll, sqlConnection); var reader = selectCommand.ExecuteReader(); while (reader.Read()) { switch (reader[SettingKeyColumnName].ToString().ToUpper()) { case DatabaseVersionKey: DatabaseVersion = new Version(reader[SettingValueColumneName].ToString()); break; case ApplicationVersionKey: ApplicationVersion = new Version(reader[SettingValueColumneName].ToString()); break; default: break; } } if (DatabaseVersion == null) throw new ApplicationException("Colud not load Database Version Setting from the database."); if (ApplicationVersion == null) throw new ApplicationException("Colud not load Application Version Setting from the database."); }

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  • Intermittent Issue Writing to Google Appengine Datastore

    - by user242153
    Hi, I have a functioning app and recently have had intermittent problems writing to the datastore. I did not make any relevant code changes, however in the last few days my attempts to write to the datastore sometimes work and sometimes don't. I am trying to save an object that is in a many to one relationship with an existing persisted parent. So, the logic works like this: 1) Parent pulled from the datastore 2) Child created / instantiated using constructor 3) Parent.addSingleChild(child); // the "addSingleChild" method just adds the object argument to the collection of children 4) child.setParent(Parent); // sets the Parent object to the parent field I am using transactions as explained in the documentation ending with "finally {if (tx.isActive()) {tx.rollback(); } }" When the servlet is called, the parent is called from the datastore and the child object is created and added to the many to one mapping to the pre-existing parent. The child should automatically be persisted, since the parent is already persistent, and the child is added to the collection of children that map to the parent. And it worked this way in the past. However, to be sure, i did add a pm.makePersistent(child). Doesn't seem to help, still have the intermittent problem. Any suggestions would be appreciated, and if you need to see the actual code I can post. Thanks

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  • Behavior of <- NULL on lists versus data.frames for removing data

    - by Ananda Mahto
    Many R users eventually figure out lots of ways to remove elements from their data. One way is to use NULL, particularly when you want to do something like drop a column from a data.frame or drop an element from a list. Eventually, a user comes across a situation where they want to drop several columns from a data.frame at once, and they hit upon <- list(NULL) as the solution (since using <- NULL will result in an error). A data.frame is a special type of list, so it wouldn't be too tough to imagine that the approaches for removing items from a list should be the same as removing columns from a data.frame. However, they produce different results, as can be seen in the example below. ## Make some small data--two data.frames and two lists cars1 <- cars2 <- head(mtcars)[1:4] cars3 <- cars4 <- as.list(cars2) ## Demonstration that the `list(NULL)` approach works cars1[c("mpg", "cyl")] <- list(NULL) cars1 # disp hp # Mazda RX4 160 110 # Mazda RX4 Wag 160 110 # Datsun 710 108 93 # Hornet 4 Drive 258 110 # Hornet Sportabout 360 175 # Valiant 225 105 ## Demonstration that simply using `NULL` does not work cars2[c("mpg", "cyl")] <- NULL # Error in `[<-.data.frame`(`*tmp*`, c("mpg", "cyl"), value = NULL) : # replacement has 0 items, need 12 Switch to applying the same concept to a list, and compare the difference in behavior. ## Does not fully drop the items, but sets them to `NULL` cars3[c("mpg", "cyl")] <- list(NULL) # $mpg # NULL # # $cyl # NULL # # $disp # [1] 160 160 108 258 360 225 # # $hp # [1] 110 110 93 110 175 105 ## *Does* drop the `list` items while this would ## have produced an error with a `data.frame` cars4[c("mpg", "cyl")] <- NULL # $disp # [1] 160 160 108 258 360 225 # # $hp # [1] 110 110 93 110 175 105 The main questions I have are, if a data.frame is a list, why does it behave so differently in this scenario? Is there a foolproof way of knowing when an element will be dropped, when it will produce an error, and when it will simply be given a NULL value? Or do we depend on trial-and-error for this?

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  • Codeigniter Session Data not available in other pages after login

    - by jswat
    So, I have set up a login page that verifies the user's credentials, and then sets codeigniter session data 'email' and 'is_logged_in' and a few other items. The first page after the login, the data is accessible. After that page, I can no longer access the session data. In fact, if I try reloading that first page, the session data is gone. I have tried storing it in the database, storing it unencrypted (bad idea I know, but it was for troubleshooting), and storing it encrypted. I have autoloaded the session library in config.php. Here's an example of the code I'm using to set the session data: $data = array( 'email' => $this->input->post('username'), 'is_logged_in' => true ); $this->session->set_userdata($data); And to retrieve it, I'm using : $this->session->userdata('email'); Or $this->session->userdata('is_logged_in'); I've done lots of work with PHP and cookies, and sessions before, but this is my first project with Codeigniter and I'm perplexed. Could it have something to do with directory issues? I have the login page and process controlled by a 'login' controller, and then it redirects to a 'site' controller. Thanks for your help, and please let me know if I need to clarify anything.

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  • about option buttons in User form

    - by Mars
    I have a question: I need to create a user form that contain that usual OK and Cancel Buttons. It also should contain two sets of Options buttons, each set placed inside a frame. The captions on the first set should be basketball, baseball, football, the captions on the second set should be watch on TV and Go to games. I need to write the event handlers and code in a module so that when the program runs, the user sees the form. If the user makes a couple of choices and clicks OK, he should see a message like "Your favorite sport is basketball, and you usually watch on TV." If the user clicks Cancel, the message "Sorry you don't want to play" should appear. I think I almost have it working, but I don't know why I cannot successfully execute the Macro. My Code is : Option Explicit Private Sub CommandButton2_Click() MsgBox ("sorry if you don't want to play") End Sub Private Sub commandbuttons_Click() Dim optbasket As String, optbaseball As String, optfootball As String Dim optwog As String, optgtg As String Select Case True Case optbasket optbasket = True Case optbaseball optbaseball = True Case optfootball optfootball = True End Select If optwog Then optwog = True Else optgtg = True End If btnok = MsgBox("you favorite sport is " & Frame1.Value & "you usually " & Frame2.Value & ",") End Sub Private Sub OptionButton1_Click() End Sub Private Sub btmcancel_Click() End Sub Private Sub btnok_Click() End Sub Private Sub Frame1_Click() End Sub Private Sub Frame2_Click() End Sub Private Sub optbaseball_Click() End Sub Private Sub optbasketball_Click() End Sub Private Sub optfootball_Click() End Sub Thank you very much!!!

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  • Arduino variable going blank after the first pass

    - by user541597
    I have an Arduino sketch that takes a timet and when that timet is equal to the current time it sets the new timet to timet + 2. For example: char* convert(char* x, String y) { int hour; int minute; sscanf(x, "%d:%d", &hour, &minute); char buf[6]; if (y == "6") { if (hour > 17) { hour = (hour+6)%24; snprintf(buf, 10, "%d:%d", hour, minute ); } else if (hour < 18) { //hour = hour + 6; minute = (minute + 2); snprintf(buf, 10, "%d:%d", hour, minute); } } if (y == "12") { if (hour > 11) { hour = (hour+12)%24; snprintf(buf, 10, "%d:%d", hour, minute ); } else if (hour < 12) { hour = hour + 12; snprintf(buf, 10, "%d:%d", hour, minute); } } if (y == "24") { hour = (hour+24)%24; snprintf(buf, 10, "%d:%d", hour, minute ); } return buf; } The sketch starts for example at 1:00am. timet is set to 1:02, at system time 1:02 timet is equal to the system time. My loops looks like this: if (timet == currenttime) { timet = convert(timet) } Whenever I check the value of timet it should equal 1:04, however I get the correct value at the first run after the execution of convert, however every time after that my timet value is blank. I tried changing the code instead of using the if loop. I only run the convert function when I send for example t through the serial monitor. This works fine and outputs the correct timet after the execution of the convert function, So I figured the problem is in the if loop... Any ideas?

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  • Setting left/top position not working in IE

    - by Brian
    Hello, In a custom ASP.NET AJAX control, i have this to do some repositioning. var dims = Sys.UI.DomElement.getBounds(control); this.get_element().style.position = "absolute"; //Sys.UI.DomElement.setLocation(this.get_element(), dims.x, (dims.y + dims.height)); this.get_element().style.left = dims.x; this.get_element().style.top = (dims.y + dims.height); getBounds simply returns the x/y and width/height. I use this to set the left/top, but in IE, it's doubling; say the coordinates are 500, 20; when it sets this on the element, its actually setting to 1000, 40. Any ideas why? In firefox, this works correctly. this.get_element() returns the correct element and all, but it's not setting correctly, even though event logging says it's the correct coordinates. When using setLocation too, it doesn't work in either... What else in my code may be affecting it? JQuery isn't an option here too. Thanks.

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  • Interpolating data points in Excel

    - by Niels Basjes
    Hi, I'm sure this is the kind of problem other have solved many times before. A group of people are going to do measurements (Home energy usage to be exact). All of them will do that at different times and in different intervals. So what I'll get from each person is a set of {date, value} pairs where there are dates missing in the set. What I need is a complete set of {date, value} pairs where for each date withing the range a value is known (either measured or calculated). I expect that a simple linear interpolation would suffice for this project. If I assume that it must be done in Excel. What is the best way to interpolate in such a dataset (so I have a value for every day) ? Thanks. NOTE: When these datasets are complete I'll determine the slope (i.e. usage per day) and from that we can start doing home-to-home comparisons. ADDITIONAL INFO After first few suggestions: I do not want to manually figure out where the holes are in my measurement set (too many incomplete measurement sets!!). I'm looking for something (existing) automatic to do that for me. So if my input is {2009-06-01, 10} {2009-06-03, 20} {2009-06-06, 110} Then I expect to automatically get {2009-06-01, 10} {2009-06-02, 15} {2009-06-03, 20} {2009-06-04, 50} {2009-06-05, 80} {2009-06-06, 110} Yes, I can write software that does this. I am just hoping that someone already has a "ready to run" software (Excel) feature for this (rather generic) problem.

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  • Why doesn't keyboard input work for a ScrollViewer when the child control has input focus?

    - by Ashley Davis
    Why doesn't keyboard input work for a ScrollViewer when the child control has input focus? This is the scenario. A WPF window opens. It sets the focus to a control that is embedded in a ScrollViewer. I hit the up and down and left and right keys. The ScrollViewer doesn't seem to handle the key events, anyone know why? This is the simplest possible example: <Window x:Class="WpfApplication1.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Window1" Height="300" Width="300" FocusManager.FocusedElement="{Binding ElementName=control}" > <Grid> <ScrollViewer HorizontalScrollBarVisibility="Auto" > <ItemsControl x:Name="control" Width="1000" Height="1000" /> </ScrollViewer> </Grid> </Window> When you start the app that contains this window, "control" appears to have the focus as I intended. Pressing the key seems to result in bubbling key events reaching the ScrollViewer (I checked for this using WPF Snoop). I can't work out why it doesn't respond to the input.

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