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  • handling DATETIME values 0000-00-00 00:00:00 in JDBC

    - by Jason S
    I get an exception (see below) if I try to do resultset.getString("add_date"); for a JDBC connection to a MySQL database containing a DATETIME value of 0000-00-00 00:00:00 (the quasi-null value for DATETIME), even though I'm just trying to get the value as string, not as an object. I got around this by doing SELECT CAST(add_date AS CHAR) as add_date which works, but seems silly... is there a better way to do this? My point is that I just want the raw DATETIME string, so I can parse it myself as is. note: here's where the 0000 comes in: (from http://dev.mysql.com/doc/refman/5.0/en/datetime.html) Illegal DATETIME, DATE, or TIMESTAMP values are converted to the “zero” value of the appropriate type ('0000-00-00 00:00:00' or '0000-00-00'). The specific exception is this one: SQLException: Cannot convert value '0000-00-00 00:00:00' from column 5 to TIMESTAMP. SQLState: S1009 VendorError: 0 java.sql.SQLException: Cannot convert value '0000-00-00 00:00:00' from column 5 to TIMESTAMP. at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1055) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:926) at com.mysql.jdbc.ResultSetImpl.getTimestampFromString(ResultSetImpl.java:6343) at com.mysql.jdbc.ResultSetImpl.getStringInternal(ResultSetImpl.java:5670) at com.mysql.jdbc.ResultSetImpl.getString(ResultSetImpl.java:5491) at com.mysql.jdbc.ResultSetImpl.getString(ResultSetImpl.java:5531)

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  • Accessing dynamically added control from GridView Footer row

    - by harold-sota
    Hi, I have GridView control in my asp.net page with auto generated fields there is only footer template is present under asp:TemplateField. I can bind this gridview with any of databae table as depend on user selection. Now want to add new record in database so I have added text boxes on footer template cells at runtime depend on number of columns on table. But when I accessing these text boxes from footer template on gridview_RowCommand event its not retriving textbox control. this is the code SGridView.ShowFooter = True For i As Integer = 0 To ctrList.Count Dim ctr As Control = CType(ctrList.Item(i), Control) SGridView.FooterRow.Cells(i + 1).Controls.Add(ctr) Next the ctrList contain Controls textBox, checkbox dropdowlist ect. there is all ok but when i wont to get the text or value or checked value of controls i cant cast the controls in rowcommand event Here is the code: Protected Sub SGridView_RowCommand(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewCommandEventArgs) Handles SGridView.RowCommand If e.CommandName = "Add" Then Dim ctrList As ControlCollection = SGridView.FooterRow.Controls For Each ctr As Control In ctrList If TypeOf ctr Is TextBox Then Dim name As TextBox = CType(ctr, TextBox) Dim val As String = name.Text End If Next End If this excample is for the textBox control. Plese suggest me how can I get footer control textboxes. So that I can save data in database.

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  • How to put foreign key constraints on a computed fields in sql server?

    - by Asaf R
    Table A has a computed field called Computed1. It's persisted and not null. Also, it always computes to an expression which is char(50). It's also unique and has a unique key constraint on it. Table B has a field RefersToComputed1, which should refer to a valid Computed1 value. Trying to create a foreign key constraint on B's RefersToComputed1 that references A' Computed1 leads to the following error: Error SQL01268: .Net SqlClient Data Provider: Msg 1753, Level 16, State 0, Line 1 Column 'B.RefersToComputed1' is not the same length or scale as referencing column 'A.Computed1' in foreign key 'FK_B_A'. Columns participating in a foreign key relationship must be defined with the same length and scale. Q: Why is this error created? Are there special measures needed for foreign keys for computed columns, and if so what are they? Summary: The specific problem rises from computed, char based, fields being varchar. Hence, Computed1 is varchar(50) and not char(50). It's best to have a cast surrounding a computed field's expression to force it to a specific type. Credit goes to Cade Roux for this tip.

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  • Design considerations for temporarily transforming a player into an animal in a role playing game

    - by mikedev
    I am working on a role playing game for fun and to practice design patterns. I would like players to be able to transform themselves into different animals. For example, a Druid might be able to shape shift into a cheetah. Right now I'm planning on using the decorator pattern to do this but my question is - how do I make it so that when a druid is in the cheetah form, they can only access skills for the cheetah? In other words, they should not be able to access their normal Druid skills. Using the decorator pattern it appears that even in the cheetah form my druid will be able to access their normal druid skills. class Druid : Character { // many cool druid skills and spells void LightHeal(Character target) { } } abstract class CharacterDecorator : Character { Character DecoratedCharacter; } class CheetahForm : CharacterDecorator { Character DecoratedCharacter; public CheetahForm(Character decoratedCharacter) { DecoratedCharacter= decoratedCharacter; } // many cool cheetah related skills void CheetahRun() { // let player move very fast } } now using the classes Druid myDruid = new Druid(); myDruid.LightHeal(myDruid); // casting light heal here is fine myDruid = new CheetahForm(myDruid); myDruid.LightHeal(myDruid); // casting here should not be allowed Hmmmm...now that I think about it, will myDruid be unable to us the Druid class spells/skills unless the class is down-casted? But even if that's the case, is there a better way to ensure that myDruid at this point is locked out from all Druid related spells/skills until it is cast back to a Druid (since currently it's in CheetahForm)

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  • Erlang OTP application design

    - by Toby Hede
    I am struggling a little coming to grips with the OTP development model as I convert some code into an OTP app. I am essentially making a web crawler and I just don't quite know where to put the code that does the actual work. I have a supervisor which starts my worker: -behaviour(supervisor). -define(CHILD(I, Type), {I, {I, start_link, []}, permanent, 5000, Type, [I]}). init(_Args) -> Children = [ ?CHILD(crawler, worker) ], RestartStrategy = {one_for_one, 0, 1}, {ok, {RestartStrategy, Children}}. In this design, the Crawler Worker is then responsible for doing the actual work: -behaviour(gen_server). start_link() -> gen_server:start_link(?MODULE, [], []). init([]) -> inets:start(), httpc:set_options([{verbose_mode,true}]), % gen_server:cast(?MODULE, crawl), % ok = do_crawl(), {ok, #state{}}. do_crawl() -> % crawl! ok. handle_cast(crawl}, State) -> ok = do_crawl(), {noreply, State}; do_crawl spawns a fairly large number of processes and requests that handle the work of crawling via http. Question, ultimately is: where should the actual crawl happen? As can be seen above I have been experimenting with different ways of triggering the actual work, but still missing some concept essential for grokering the way things fit together. Note: some of the OTP plumbing is left out for brevity - the plumbing is all there and the system all hangs together

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  • C# Inheritence: Choosing what repository based on type of inherited class

    - by Oskar Kjellin
    I have been making a program that downloads information about movies from the internet. I have a base class Title, which represents all titles. Movie, Serie and Episode are inherited from that class. To save them to the database I have 2 services, MovieService and SerieService. They in turn call repositories, but that is not important here. I have a method Save(Title title) which I am not very happy with. I check for what type the title is and then call the correct service. I would like to perhaps write like this: ITitleService service = title.GetService(); title.GetSavedBy(service); So I have an abstract method on Title that returns an ITitleSaver, which will return the correct service for the instance. My question is how should I implement ITitleSaver? If I make it accept Title I will have to cast it to the correct type before calling the correct overload. Which will lead to having to deal with casting once again. What is the best approach to dealing with this? I would like to have the saving logic in the corresponding class.

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  • Calling MethodBase's Invoke on a constructor (reflection)

    - by Alix
    Hi everyone. First of all, sorry if this has been asked before. I've done a pretty comprehensive search and found nothing quite like it, but I may have missed something. And now to the question: I'm trying to invoke a constructor through reflection, with no luck. Basically, I have an object that I want to clone, so I look up the copy constructor for its type and then want to invoke it. Here's what I have: public Object clone(Object toClone) { MethodBase copyConstructor = type.GetConstructor( new Type[] { toClone.GetType() }); return method.Invoke(toClone, new object[] { toClone }); //<-- doesn't work } I call the above method like so: List list = new List(new int[] { 0, 1, 2 }); List clone = (List) clone(list); Now, notice the invoke method I'm using is MethodBase's invoke. ConstructorInfo provides an invoke method that does work if invoked like this: return ((ConstructorInfo) method).Invoke(new object[] { toClone }); However, I want to use MethodBase's method, because in reality instead of looking up the copy constructor every time I will store it in a dictionary, and the dictionary contains both methods and constructors, so it's a Dictionary<MethodBase>, not Dictionary<ConstructorInfo>. I could of course cast to ConstructorInfo as I do above, but I'd rather avoid the casting and use the MethodBase method directly. I just can't figure out the right parameters. Any help? Thanks so much.

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  • Mapping self-table one-to-many using non-PK clolumns

    - by Harel Moshe
    Hey, i have a legacy DB to which a Person object is mapped, having a collection of family-members, like this: class Person { ... string Id; /* 9-digits string */ IList<Person> Family; ... } The PERSON table seems like: Id: CHAR(9), PK FamilyId: INT, NOT NULL and several other non-relevant columns. I'm trying to map the Family collection to the PERSON table using the FamilyId column, which is not the PK as mentioned above. So, i actually have a one-to-many which is self-table-referential. I'm getting an error saying 'Cast is not valid' when my mapping looks like this: ... <set name="Family" table="Person" lazy="false"> <key column="FamilyId" /> <one-to-many class="Person" /> </set> ... because obviously, the join NHibernate is trying to make is between the PK column, Id, and the 'secondary' column, FamilyId, instead of joining the FamilyId column to itself. Any ideas please?

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  • Generic list typecasting problem

    - by AJ
    Hello, I'm new to C# and am stuck on the following. I have a Silverlight web service that uses LINQ to query a ADO.NET entity object. e.g.: [OperationContract] public List<Customer> GetData() { using (TestEntities ctx = new TestEntities()) { var data = from rec in ctx.Customer select rec; return data.ToList(); } } This works fine, but what I want to do is to make this more abstract. The first step would be to return a List<EntityObject> but this gives a compiler error, e.g.: [OperationContract] public List<EntityObject> GetData() { using (TestEntities ctx = new TestEntities()) { var data = from rec in ctx.Customer select rec; return data.ToList(); } } The error is: Error 1 Cannot implicitly convert type 'System.Collections.Generic.List<SilverlightTest.Web.Customer>' to 'System.Collections.Generic.IEnumerable<System.Data.Objects.DataClasses.EntityObject>'. An explicit conversion exists (are you missing a cast?) What am i doing wrong? Thanks, AJ

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  • c# scope/typing/assignment question

    - by Shannow
    Hi there another quick question. I would like to create a variable object so that depending on the value of something, it gets cast as needed. e.g. var rule; switch (seqRuleObj.RuleType) { case SeqRuleObj.type.Pre : rule = new preConditionRuleType(); rule = (preConditionRuleType)seqRuleObj.Rule; break; case SeqRuleObj.type.Post : rule = new postConditionRuleType(); rule = (postConditionRuleType)seqRuleObj.Rule; break; case SeqRuleObj.type.Exit : rule = new exitConditionRuleType(); rule = (exitConditionRuleType)seqRuleObj.Rule; break; default : break; } String result; foreach (sequencingRuleTypeRuleConditionsRuleCondition cond in rule.ruleConditions.ruleCondition) { ....../ blah } so basically this will not work. c# will not allow me to create an new object in every case as the name is aleady defined. i can just paste the foreach loop into each case but that to me is such a waste, as the objects are exactly the same in all but name.

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  • Asp.Net Random Error

    - by John Boker
    At random times, twice in the past two weeks, the we application will start to error and not work until I recycle the app pool in IIS. The specific error and stacktrace are: System.Web.HttpUnhandledException: Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> System.InvalidCastException: Unable to cast object of type 'System.Guid' to type 'System.String'. at System.Data.Linq.SqlClient.SqlProvider.Execute(Expression query, QueryInfo queryInfo, IObjectReaderFactory factory, Object[] parentArgs, Object[] userArgs, ICompiledSubQuery[] subQueries, Object lastResult) at System.Data.Linq.SqlClient.SqlProvider.ExecuteAll(Expression query, QueryInfo[] queryInfos, IObjectReaderFactory factory, Object[] userArguments, ICompiledSubQuery[] subQueries) at System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query) at System.Data.Linq.DataQuery`1.System.Linq.IQueryProvider.Execute[S](Expression expression) at System.Linq.Queryable.FirstOrDefault[TSource](IQueryable`1 source) at DigitalScout.WEDS.Business.Slug.GetTeamPath(String teamID) at DigitalScout.WEDS.WebApp.Code.Navigator.TeamNavigator.Home(String teamID) at ASP.management_default_aspx.__DataBind__control7(Object sender, EventArgs e) at System.Web.UI.Control.OnDataBinding(EventArgs e) at System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding) at System.Web.UI.Control.DataBindChildren() at System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding) at System.Web.UI.WebControls.Repeater.CreateControlHierarchy(Boolean useDataSource) at System.Web.UI.WebControls.Repeater.OnDataBinding(EventArgs e) at System.Web.UI.Control.DataBindChildren() at System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding) at System.Web.UI.WebControls.Repeater.CreateControlHierarchy(Boolean useDataSource) at System.Web.UI.WebControls.Repeater.OnDataBinding(EventArgs e) at DigitalScout.WEDS.WebApp.Management._default.Page_Load(Object sender, EventArgs e) at System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) at System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) at System.Web.UI.Control.OnLoad(EventArgs e) at DigitalScout.WEDS.WebApp.Code.BaseClass.Pages.ManagementPage.OnLoad(EventArgs e) at System.Web.UI.Control.LoadRecursive() at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) --- End of inner exception stack trace --- at System.Web.UI.Page.HandleError(Exception e) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) at System.Web.UI.Page.ProcessRequest() at System.Web.UI.Page.ProcessRequest(HttpContext context) at ASP.management_default_aspx.ProcessRequest(HttpContext context) at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) This error happens for every user of the system until the app pool is recycled. Any help on this would be helpful as we are not able to reproduce the error.

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  • SubSonic 3.0 Simple Repository Adding a DateTime Property To An Object

    - by Blounty
    I am trying out SubSonic to see if it is viable to use on production projects. I seem to have stumbled upon an issue whith regards to updating the database with default values (String and DateTime) when a new column is created. If a new property of DateTime or String is added to an object. public class Bug { public int BugId { get; set; } public string Title { get; set; } public string Overview { get; set; } public DateTime TrackedDate { get; set; } public DateTime RemovedDate { get; set; } } When the code to add that type of object to the database is run var repository = new SimpleRepository(SimpleRepositoryOptions.RunMigrations); repository.Add(new Bug() { Title = "A Bug", Overview = "An Overview", TrackedDate = DateTime.Now }); it creates the following sql: UPDATE Bugs SET RemovedDate=''01/01/1900 00:00:00'' For some reason it is adding double 2 single quotes to each end of the string or DateTime. This is causing the following error: System.Data.SqlClient.SqlException - Incorrect syntax near '01' I am connecting to SQL Server 2005 Any help would be appreicated as apart from this issue i am finding SubSonic to be a great product. I have created a screen cast of my error here:

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  • How to retrieve value from ViewData when the object is not a string?

    - by Richard77
    Hello, Here's the functionality I'd like to exploit: I've a class myClass and would like to iterate over a collection that contains all the properties of that class. I'd like to send the index of that collection along with the other data so that I can control the each sequence of the iteration. Here's simplified versions of a Action method and View (I'll use the same action-view for that functionality). 1) Action public ActionResult CreateHierarchy(int? index) { if(index < PropertiesOfMyClass.Lenght) { //Other code omitted ViewData["index"] = ((index == null) ? 1 : index++); Return View(); } } 2)View <% Using(Html.BeginForm()){%> //Other Code omitted <% = Html.Hidden("Index", ViewData["index"])%> <input type = "submit" value = "Do someting"/> <%}%> I've also placed this at the bottom of the page so that I can check the value of the index, <% = ViewData["index"]%> Unfortunately, its not working. I'm getting only the number 1. I'm missing something? such as a cast for the Viewdata? Should I write something like this: <% = Html.Hidden("index", (int)ViewData["index"])%> It's not working either Thanks for helping

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  • Why does a conditional not affect query speed?

    - by Telos
    I have a stored procedure that was taking a "long" period of time to execute. The query only needs to return data in one case, so I figured I could check for that case and just return before hitting the actual query. The only problem is that it still takes the same amount of time to execute with an if statement. I have verified that the code inside the if is not executing, and that if I replace the complex query with a simple select the speed is fine... so now I'm confused. Why is the query being slowed down by code that doesn't get executed when the conditional is false? Here's the query itself: ALTER PROCEDURE [dbo].[pr_cbc_GetCokeInfo] @pa_record int, @pb_record int AS BEGIN SET NOCOUNT ON; declare @ticketRec int SELECT @ticketRec = TicketRecord FROM eservice_live..v_sdticket where TicketRecord=@pa_record AND serviceCompanyID = 1139 AND @pb_record IS NULL if @ticketRec IS NULL return select record = null, doc_ref = @pa_record, memo_type = 'I', memo = 'Bottler: ' + isnull(Bottler, '') + ' ' + 'Sales Loc: ' + isnull(SalesLocation, '') + ' ' + 'Outlet Desc: ' + isnull(OutletDesc, '') + ' ' + 'City: ' + isnull(OutletCity, '') + ' ' + 'EquipNo: ' + isnull(EquipNo, '') + ' ' + 'SerialNo: ' + isnull(SerialNo, '') + ' ' + 'PhaseNo: ' + isnull(cast(PhaseNo as varchar(255)), '') + ' ' + 'StaticIP: ' + isnull(StaticIP, '') + ' ' + 'Air Card: ' + isnull(AirCard, '') FROM eservice_live..v_SDExtendedInfoField ef JOIN eservice_live..CokeSNList csl ON ef.valueText=csl.SerialNo where ef.docType='CLH' AND ef.docref = @ticketRec AND ef.ExtendedDocNumber=5 SET NOCOUNT OFF; END

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  • Binding a date string parameter in an MS Access PDO query

    - by harryg
    I've made a PDO database class which I use to run queries on an MS Access database. When querying using a date condition, as is common in SQL, dates are passed as a string. Access usually expects the date to be surrounded in hashes however. E.g. SELECT transactions.amount FROM transactions WHERE transactions.date = #2013-05-25#; If I where to run this query using PDO I might do the following. //instatiate pdo connection etc... resulting in a $db object $stmt = $db->prepare('SELECT transactions.amount FROM transactions WHERE transactions.date = #:mydate#;'); //prepare the query $stmt->bindValue('mydate', '2013-05-25', PDO::PARAM_STR); //bind the date as a string $stmt->execute(); //run it $result = $stmt->fetch(); //get the results As far as my understanding goes the statement that results from the above would look like this as binding a string results in it being surrounded by quotes: SELECT transactions.amount FROM transactions WHERE transactions.date = #'2013-05-25'#; This causes an error and prevents the statement from running. What's the best way to bind a date string in PDO without causing this error? I'm currently resorting to sprintf-ing the string which I'm sure is bad practise. Edit: if I pass the hash-surrounded date then I still get the error as below: Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[22018]: Invalid character value for cast specification: -3030 [Microsoft][ODBC Microsoft Access Driver] Data type mismatch in criteria expression. (SQLExecute[-3030] at ext\pdo_odbc\odbc_stmt.c:254)' in C:\xampp\htdocs\ips\php\classes.php:49 Stack trace: #0 C:\xampp\htdocs\ips\php\classes.php(49): PDOStatement-execute() #1 C:\xampp\htdocs\ips\php\classes.php(52): database-execute() #2 C:\xampp\htdocs\ips\try2.php(12): database-resultset() #3 {main} thrown in C:\xampp\htdocs\ips\php\classes.php on line 49

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  • Converting an int64 value to a Number object in JavaScript

    - by Matt
    I have a COM object which has a method that returns an unsigned int64 (VT_UI8) value. We have an HTML page which contains some JavaScript which can load the COM object and make the call to that method, to retrieve the value as such: var foo = MyCOMObject.GetInt64Value(); This value can easily be displayed to the user in a message dialog using: alert(foo); or displayed on the page by: document.getElementById('displayToUser').innerHTML = foo; However, we cannot use this value as a Number (e.g. if we try to multiply it by 2) without the page throwing "Number expected" errors. If we check "typeof(foo)" it returns "unknown". I've found a workaround for this by doing the following: document.getElementById('displayToUser').innerHTML = foo; var bar = parseInt(document.getElementById('displayToUser').innerHTML); alert(bar*2); What I need to know is how to make that process more efficient. Specifically, is there a way to cast foo to a String explicitly, rather than having to set some document element's innerHTML to foo and then retrieve it from that. I wouldn't mind calling something like: alert(parseInt((string)foo) * 2); Even better would be if there is a way to directly convert the int64 to a Number, without going through the String conversion, but I hold out less hope for that.

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  • subtotals in columns usind reshape2 in R

    - by user1043144
    I have spent some time now learning RESHAPE2 and plyr but I still do not get it. This time I have a problem with (a) subtotals and (b) passing different aggregate functions . Here an example using data from the excellent tutorial on the blog of mrdwab http://news.mrdwab.com/ # libraries library(plyr) library(reshape2) # get data and add few more variables book.sales = read.csv("http://news.mrdwab.com/data-booksales") book.sales$Stock = book.sales$Quantity + 10 book.sales$SubjCat[(book.sales$Subject == 'Economics') | (book.sales$Subject == 'Management') ] <- '1_EconSciences' book.sales$SubjCat[book.sales$Subject %in% c('Anthropology', 'Politics', 'Sociology') ] <- '2_SocSciences' book.sales$SubjCat[book.sales$Subject %in% c('Communication', 'Fiction', 'History', 'Research', 'Statistics') ] <- '3_other' # to get to my starting dataframe (close to the project I am working on) book.sales1 <- ddply(book.sales, c('Region', 'Representative', 'SubjCat', 'Subject', 'Publisher'), summarize, Stock = sum(Stock), Sold = sum(Quantity), Ratio = round((100 * sum(Quantity)/ sum(Stock)), digits = 1)) #melt it m.book.sales = melt(data = book.sales1, id.vars = c('Region', 'Representative', 'SubjCat', 'Subject', 'Publisher'), measured.vars = c('Stock', 'Sold', 'Ratio')) # cast it Tab1 <- dcast(data = m.book.sales, formula = Region + Representative ~ Publisher + variable, fun.aggregate = sum, margins = c('Region', 'Representative')) Now my questions : I have been able to add the subtotals in rows. But is it possible also to add margins in the columns. Say for example, Totals of Stock for one Publisher ? Sorry I meant to say example total sold for all publishers There is a problem with the columns with “ratio”. How can I get “mean” instead of “sum” for this variable ? P.S: I have seen some examples using reshape. Will you recommend to use it instead of reshape2 (which seems not to include the functionalities of two functions).

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  • getting proxies of the correct type in nhibernate

    - by Nir
    I have a problem with uninitialized proxies in nhibernate The Domain Model Let's say I have two parallel class hierarchies: Animal, Dog, Cat and AnimalOwner, DogOwner, CatOwner where Dog and Cat both inherit from Animal and DogOwner and CatOwner both inherit from AnimalOwner. AnimalOwner has a reference of type Animal called OwnedAnimal. Here are the classes in the example: public abstract class Animal { // some properties } public class Dog : Animal { // some more properties } public class Cat : Animal { // some more properties } public class AnimalOwner { public virtual Animal OwnedAnimal {get;set;} // more properties... } public class DogOwner : AnimalOwner { // even more properties } public class CatOwner : AnimalOwner { // even more properties } The classes have proper nhibernate mapping, all properties are persistent and everything that can be lazy loaded is lazy loaded. The application business logic only let you to set a Dog in a DogOwner and a Cat in a CatOwner. The Problem I have code like this: public void ProcessDogOwner(DogOwner owner) { Dog dog = (Dog)owner.OwnedAnimal; .... } This method can be called by many diffrent methods, in most cases the dog is already in memory and everything is ok, but rarely the dog isn't already in memory - in this case I get an nhibernate "uninitialized proxy" but the cast throws an exception because nhibernate genrates a proxy for Animal and not for Dog. I understand that this is how nhibernate works, but I need to know the type without loading the object - or, more correctly I need the uninitialized proxy to be a proxy of Cat or Dog and not a proxy of Animal. Constraints I can't change the domain model, the model is handed to me by another department, I tried to get them to change the model and failed. The actual model is much more complicated then the example and the classes have many references between them, using eager loading or adding joins to the queries is out of the question for performance reasons. I have full control of the source code, the hbm mapping and the database schema and I can change them any way I want (as long as I don't change the relationships between the model classes). I have many methods like the one in the example and I don't want to modify all of them. Thanks, Nir

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  • Movies recommendation engine conceptual database design

    - by Supyxy
    I am working at an movie recommendations engine and i'm facing a DB design issue. My actual database looks like this: MOVIES [ID,TITLE] KEYWORDS_TABLE [ID,KEY_ID] - where ID is Foreign Key for MOVIES.id and KEY_ID is a key for a text keywords table This is not the entire DB, but i showed here what's important for my problem. I have about 50,000 movies and about 1,3 milion keywords correlations, and basically my algorithm consists in extracting all the who have the same keywords with a given movie, then ordering them by the number of keywords correlations. For example i looked for a movie similar to 'Cast away' and it returned 'Six days and six nights' because it had the most keywords correlations (4 keywords): Island Airplane crash Stranded Pilot The algorithm is based on more factors, but this one is the most important and the most difficult for the approach. Basically what i do now is getting all the movies that have at least one keyword similar to the given movie and then ordering them by other factors which are not important for a moment. There wouldn't be any problem if there weren't so many records, a query lasts in many cases up to 10-20 seconds and some of them return even over 5000 movies. Someone already helped me on here (thanks Mark Byers) with optimizing the query but that's not enough because it takes too longer SELECT DISTINCT M.title FROM keywords_table K1 JOIN keywords_table K2 ON K2.key_id = K1.key_id JOIN movies M ON K2.id = M.id WHERE K1.id = 4 So i thought it would be better if i pre-made those lists with movies recommendations for each movie, but i'm not sure how to design the tables.. whatever is it a good idea or how would you take this approach?

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  • To what degree should I use Marshal.ReleaseComObject with Excel Interop objects?

    - by DanM
    I've seen several examples where Marshal.ReleaseComObject() is used with Excel Interop objects (i.e., objects from namespace Microsoft.Office.Interop.Excel), but I've seen it used to various degrees. I'm wondering if I can get away with something like this: var application = new ApplicationClass(); try { // do work with application, workbooks, worksheets, cells, etc. } finally { Marashal.ReleaseComObject(application) } Or if I need to release every single object created, as in this method: public void CreateExcelWorkbookWithSingleSheet() { var application = new ApplicationClass(); var workbook = application.Workbooks.Add(_missing); var worksheets = workbook.Worksheets; for (var worksheetIndex = 1; worksheetIndex < worksheets.Count; worksheetIndex++) { var worksheet = (WorksheetClass)worksheets[worksheetIndex]; worksheet.Delete(); Marshal.ReleaseComObject(worksheet); } workbook.SaveAs( WorkbookPath, _missing, _missing, _missing, _missing, _missing, XlSaveAsAccessMode.xlExclusive, _missing, _missing, _missing, _missing, _missing); workbook.Close(true, _missing, _missing); application.Quit(); Marshal.ReleaseComObject(worksheets); Marshal.ReleaseComObject(workbook); Marshal.ReleaseComObject(application); } What prompted me to ask this question is that, being the LINQ devotee I am, I really want to do something like this: var worksheetNames = worksheets.Cast<Worksheet>().Select(ws => ws.Name); ...but I'm concerned I'll end up with memory leaks or ghost processes if I don't release each worksheet (ws) object. Any insight on this would be appreciated.

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  • F# exercise help - Beginner

    - by bobjink
    I hope you can help me with these exercises I have been stuck with. I am not in particular looking for the answers. Tips that help me solve them myself are just as good :) 1. Write a function implode : char list - string so that implode s returns the characters concatenated into a string: let implode (cArray:char list) = List.foldBack (+) 0 cArray;; Error. I am thinking that i need to cast every char to strings before I do the above. I bet however, that there is a much simpler and better solution. 2. Write a function palindrome : string - bool, so that palindrome s returns true if the string s is a palindrome let isIdentical cArray1 cArray2 = (cArray1 = cArray2);; let palinDrome (word:string) = isIdentical(word.ToCharArray(), Array.rev(word.ToCharArray()));; I get the value: val palinDrome : string - (char [] * char [] - bool), which is not what I want. 3. Write a function combinePair : int list - int list so that combinePair xs returns the list with elements from xs combined into pairs. If xs contains an odd number of elements, then the last element is thrown away: I have no idea for this one.

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  • How to decode base64-encoded <data> (CFData/NSData) property in a property list?

    - by bantic
    I am trying to reverse-engineer a preferences file (not for any nefarious purposes, just so that I can script usage of it) that, among other things, has arrays of coordinates stored within it. This is the salient snippet from the property list: <dict> <key>$class</key> <dict> <key>CF$UID</key> <integer>34</integer> </dict> <key>coordArray</key> <data> AAAAAAAAAAAAAAAAAAAAAT70vS8/M7xSPwAAAD8AAAA/AAAA </data> <key>coordCount</key> <integer>1</integer> </dict> I assume that data string is an array of coordinates (based on its key name). My question is, how can I figure out what data is stored there? If I simply base64-decode that string, I get gibberish. Is there a way to decode it and cast it into whatever format it came from (NSArray, I think)?

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  • JPA/Hibernate query with class name?

    - by Petteri Hietavirta
    In this example com.test.Cat extends com.test.Animal and there is no field DB in CAT table of com.test.Cat explicitly defining its type (it wasn't me). When I query my animals from DB I get a collection of Animals. It is possible to sort them by class name: order by r.class but is there a way to use class name as a criteria? For example I would like to get all animals expect dogs. But no luck - even this does not work: where r.class = ? (String "ccc.test.Cat") as I get an exception: Caused by: java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Integer at org.hibernate.type.IntegerType.set(IntegerType.java:64) at org.hibernate.type.NullableType.nullSafeSet(NullableType.java:154) at org.hibernate.type.NullableType.nullSafeSet(NullableType.java:136) at org.hibernate.param.PositionalParameterSpecification.bind(PositionalParameterSpecification.java:62) at org.hibernate.loader.hql.QueryLoader.bindParameterValues(QueryLoader.java:514) at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1589) at org.hibernate.loader.Loader.doQuery(Loader.java:696) at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259) at org.hibernate.loader.Loader.doList(Loader.java:2228) at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2125) at org.hibernate.loader.Loader.list(Loader.java:2120) at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:401) at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:361) at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196) at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1148) at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102) at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:67)

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  • Updating multiple divs w/ RJS/AJAX

    - by bgadoci
    I am successfully using RJS to implement AJAX on a page.replace.html create.js.rjs. I am attempting to update two locations instead of one and after watching Ryan Bates Railscast I am very close (I think) but have a problem in the syntax of my /views/likes/create.js.rjs file. Here is the situation: located at /views/likes/create.js.rjs is the following code: page.replace_html "votes_#{ @site.id }", :partial => @like page.replace_html "counter", 10 - (@question.likes.count :conditions => {:user_id => current_user.id}) page[@like].visual_effect :highlight My problem lies in the second line. The div "counter" displays the following code in the /views/question/show.html.erb page: <div id="counter"> You have <%= 10 - (@question.likes.count :conditions => {:user_id => current_user.id}) %> votes remaining for this question </div> From watching the screen cast I believe that my error has to do w/ the syntax of the second line. Specifically he mentions that you cannot use a local instance variable but not sure how to make the change. Thoughts?

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  • Discover generic types

    - by vittore
    Thanks @dtb for help, he advised really need piece of code for generic service locator static class Locator { private static class LocatorEntry<T> where T : ... { public static IDataManager<T> instance; } public static void Register<T>(IDataManager<T> instance) where T : ... { LocatorEntry<T>.instance = instance; } public static IDataManager<T> GetInstance<T>() where T : ... { return LocatorEntry<T>.instance; } } However in my previous version I used reflection on assembly to discover a hundred of DataManager's I want to write an method discover like the following void Discover() { var pManager = new ProtocolSQLDataManager(); Register(pManager); var rManager = new ResultSQLDataManager(); Register(rManager); var gType = typeof(ISQLDataAccessManager<>); foreach (Type type in Assembly.GetExecutingAssembly().GetTypes()) { if (type.IsSubclassOf(gType) && !type.IsAbstract)) { var manager = Activator.CreateInstance(type); // put something here in order to make next line of code works Register<T>(manager); } } } How to cast type to appropriate type in order to make Register working( and call appropriate Register ?

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