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  • Where does the data model go in a Prism app?

    - by HawkeyeJoeS
    I'm having trouble where to put our data model in our Prism app. Most, if not all or our data will be coming from web services and the web services are unique for each module. Unfortunately, there will be objects that need to be shared (such as a person/user object). I'm really torn about whether to add these services directly to the module, so that each is truly independent, or create a separate project to house the web service proxies and business entities. The modules are being built by different teams, but will all live in the same solution (and source control, of course).

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  • Add fields to Django ModelForm that aren't in the model

    - by Cyclic
    I have a model that looks like: class MySchedule(models.Model): start_datetime=models.DateTimeField() name=models.CharField('Name',max_length=75) With it comes its ModelForm: class MyScheduleForm(forms.ModelForm): startdate=forms.DateField() starthour=forms.ChoiceField(choices=((6,"6am"),(7,"7am"),(8,"8am"),(9,"9am"),(10,"10am"),(11,"11am"), (12,"noon"),(13,"1pm"),(14,"2pm"),(15,"3pm"),(16,"4pm"),(17,"5pm"), (18,"6pm" startminute=forms.ChoiceField(choices=((0,":00"),(15,":15"),(30,":30"),(45,":45")))),(19,"7pm"),(20,"8pm"),(21,"9pm"),(22,"10pm"),(23,"11pm"))) class Meta: model=MySchedule def clean(self): starttime=time(int(self.cleaned_data.get('starthour')),int(self.cleaned_data.get('startminute'))) return self.cleaned_data try: self.instance.start_datetime=datetime.combine(self.cleaned_data.get("startdate"),starttime) except TypeError: raise forms.ValidationError("There's a problem with your start or end date") Basically, I'm trying to break the DateTime field in the model into 3 more easily usable form fields -- a date picker, an hour dropdown, and a minute dropdown. Then, once I've gotten the three inputs, I reassemble them into a DateTime and save it to the model. A few questions: 1) Is this totally the wrong way to go about doing it? I don't want to create fields in the model for hours, minutes, etc, since that's all basically just intermediary data, so I'd like a way to break the DateTime field into sub-fields. 2) The difficulty I'm running into is when the startdate field is blank -- it seems like it never gets checked for non-blankness, and just ends up throwing up a TypeError later when the program expects a date and gets None. Where does Django check for blank inputs, and raise the error that eventually goes back to the form? Is this my responsibility? If so, how do I do it, since it doesn't evaluate clean_startdate() since startdate isn't in the model. 3) Is there some better way to do this with inheritance? Perhaps inherit the MyScheduleForm in BetterScheduleForm and add the fields there? How would I do this? (I've been playing around with it for over an hours and can't seem to get it) Thanks! [Edit:] Left off the return self.cleaned_data -- lost it in the copy/paste originally

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  • Custom DateTime model binder in Asp.net MVC

    - by Robert Koritnik
    I would like to write my own model binder for DateTime type. First of all I'd like to write a new attribute that I can attach to my model property like: [DateTimeFormat("d.M.yyyy")] public DateTime Birth { get; set,} This is the easy part. But the binder part is a bit more difficult. I would like to add a new model binder for type DateTime. I can either implement IModelBinder interface and write my own BindModel() method inherit from DefaultModelBinder and override BindModel() method My model has a property as seen above (Birth). So when the model tries to bind request data to this property, my model binder's BindModel(controllerContext, bindingContext) gets invoked. Everything ok, but. How do I get property attributes from controller/bindingContext, to parse my date correctly? How can I get to the PropertyDesciptor of property Birth? Edit Because of separation of concerns my model class is defined in an assembly that doesn't (and shouldn't) reference System.Web.MVC assembly. Setting custom binding (similar to Scott Hanselman's example) attributes is a no-go here.

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  • Explaining the forecasts from an ARIMA model

    - by Samik R.
    I am trying to explain to myself the forecasting result from applying an ARIMA model to a time-series dataset. The data is from the M1-Competition, the series is MNB65. For quick reference, I have a google doc spreadsheet with the data. I am trying to fit the data to an ARIMA(1,0,0) model and get the forecasts. I am using R. Here are some output snippets: > arima(x, order = c(1,0,0)) Series: x ARIMA(1,0,0) with non-zero mean Call: arima(x = x, order = c(1, 0, 0)) Coefficients: ar1 intercept 0.9421 12260.298 s.e. 0.0474 202.717 > predict(arima(x, order = c(1,0,0)), n.ahead=12) $pred Time Series: Start = 53 End = 64 Frequency = 1 [1] 11757.39 11786.50 11813.92 11839.75 11864.09 11887.02 11908.62 11928.97 11948.15 11966.21 11983.23 11999.27 I have a few questions: (1) How do I explain that although the dataset shows a clear downward trend, the forecast from this model trends upward. This also happens for ARIMA(2,0,0), which is the best ARIMA fit for the data using auto.arima (forecast package) and for an ARIMA(1,0,1) model. (2) The intercept value for the ARIMA(1,0,0) model is 12260.298. Shouldn't the intercept satisfy the equation: C = mean * (1 - sum(AR coeffs)), in which case, the value should be 715.52. I must be missing something basic here. (3) This is clearly a series with non-stationary mean. Why is an AR(2) model still selected as the best model by auto.arima? Could there be an intuitive explanation? Thanks.

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  • Pass ng-model and place-holder value into directive

    - by Zen
    I have a segment of code needs to be reuse a lot, there for I want to just create a directive for it. <div class="btn-group"> <div class="input-group"> <div class="has-feedback"> <input type="text" class="form-control" placeholder="BLAH BLAH" ng-model="model"> <span class="times form-control-feedback" ng-click="model=''" ng-show="model.length > 0"></span> </div> </div> </div> I want to use this code as template in directive. Create a directive used as follow: <div search-Field ng-model="model" placeholder="STRING"></div> to replace to old html, ng-model and placeholder will be as variables. angular.module('searchField', []) .directive('searchField', [function () { return { scope: { placeholder: '@', ngModel: '=' }, templateUrl: 'Partials/_SearchInputGroup.html' } }]); Is it the way of doing it?

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  • How does Backbone.js connect View to Model

    - by William Sham
    I am trying to learn backbone.js through the following example. Then I got stuck at the point ItemView = Backbone.View.extend why you can use this.model.get? I thought this is referring to the instance of ItemView that would be created. Then why would ItemView has a model property at all?!! (function($){ var Item = Backbone.Model.extend({ defaults: { part1: 'hello', part2: 'world' } }); var List = Backbone.Collection.extend({ model: Item }); var ItemView = Backbone.View.extend({ tagName: 'li', initialize: function(){ _.bindAll(this, 'render'); }, render: function(){ $(this.el).html('<span>'+this.model.get('part1')+' '+this.model.get('part2')+'</span>'); return this; } }); var ListView = Backbone.View.extend({ el: $('body'), events: { 'click button#add': 'addItem' }, initialize: function(){ _.bindAll(this, 'render', 'addItem', 'appendItem'); this.collection = new List(); this.collection.bind('add', this.appendItem); this.counter = 0; this.render(); }, render: function(){ $(this.el).append("<button id='add'>Add list item</button>"); $(this.el).append("<ul></ul>"); _(this.collection.models).each(function(item){ appendItem(item); }, this); }, addItem: function(){ this.counter++; var item = new Item(); item.set({ part2: item.get('part2') + this.counter }); this.collection.add(item); }, appendItem: function(item){ var itemView = new ItemView({ model: item }); $('ul', this.el).append(itemView.render().el); } }); var listView = new ListView(); })(jQuery);

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  • Domain Models (PHP)

    - by Calum Bulmer
    I have been programming in PHP for several years and have, in the past, adopted methods of my own to handle data within my applications. I have built my own MVC, in the past, and have a reasonable understanding of OOP within php but I know my implementation needs some serious work. In the past I have used an is-a relationship between a model and a database table. I now know after doing some research that this is not really the best way forward. As far as I understand it I should create models that don't really care about the underlying database (or whatever storage mechanism is to be used) but only care about their actions and their data. From this I have established that I can create models of lets say for example a Person an this person object could have some Children (human children) that are also Person objects held in an array (with addPerson and removePerson methods, accepting a Person object). I could then create a PersonMapper that I could use to get a Person with a specific 'id', or to save a Person. This could then lookup the relationship data in a lookup table and create the associated child objects for the Person that has been requested (if there are any) and likewise save the data in the lookup table on the save command. This is now pushing the limits to my knowledge..... What if I wanted to model a building with different levels and different rooms within those levels? What if I wanted to place some items in those rooms? Would I create a class for building, level, room and item with the following structure. building can have 1 or many level objects held in an array level can have 1 or many room objects held in an array room can have 1 or many item objects held in an array and mappers for each class with higher level mappers using the child mappers to populate the arrays (either on request of the top level object or lazy load on request) This seems to tightly couple the different objects albeit in one direction (ie. a floor does not need to be in a building but a building can have levels) Is this the correct way to go about things? Within the view I am wanting to show a building with an option to select a level and then show the level with an option to select a room etc.. but I may also want to show a tree like structure of items in the building and what level and room they are in. I hope this makes sense. I am just struggling with the concept of nesting objects within each other when the general concept of oop seems to be to separate things. If someone can help it would be really useful. Many thanks

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  • Should Business Interfaces be part of the Model layer?

    - by Mik378
    In an oriented-services enterprise application, isn't it an antipattern to mix Service APIs (containing interface that external users depends on) with Model objects (entities, custom exceptions objects etc...) ? According to me, Services should only depends on Model layer but never mixed with it. In fact, my colleague told me that it doesn't make sense to separate it since client need both. (model and service interfaces) But I notice that everytime a client asks for some changes, like adding a new method in some interface (means a new service), Model layer has to be also delivered... Thus, client who has not interested by this "addition" is constrained to be concerned by this update of Model... and in a large enterprise application, this kind of delivery is known to be very risked... What is the best practice ? Separate services(only interfaces so) and model objects or mix it ?

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  • Is there a way to customize how the value for a custom Model Field is displayed in a template?

    - by Jordan Reiter
    I am storing dates as an integer field in the format YYYYMMDD, where month or day is optional. I have the following function for formatting the number: def flexibledateformat(value): import datetime, re try: value = str(int(value)) except: return None match = re.match(r'(\d{4})(\d\d)(\d\d)$',str(value)) if match: year_val, month_val, day_val = [int(v) for v in match.groups()] if day_val: return datetime.datetime.strftime(datetime.date(year_val,month_val,day_val),'%b %e, %Y') elif month_val: return datetime.datetime.strftime(datetime.date(year_val,month_val,1),'%B %Y') else: return str(year_val) Which results in the following outputs: >>> flexibledateformat(20100415) 'Apr 15, 2010' >>> flexibledateformat(20100400) 'April 2010' >>> flexibledateformat(20100000) '2010' So I'm wondering if there's a function I can add under the model field class that would automatically call flexibledateformat. So if there's a record r = DataRecord(name='foo',date=20100400) when processed in the form the value would be 20100400 but when output in a template using {{ r.date }} it shows up as "April 2010". Further clarification I do normally use datetime for storing date/time values. In this specific case, I need to record non-specific dates: "x happened in 2009", "y happened sometime in June 1996". The easiest way to do this while still preserving most of the functionality of a date field, including sorting and filtering, is by using an integer in the format of yyyymmdd. That is why I am using an IntegerField instead of a DateTimeField. This is what I would like to happen: I store what I call a "Flexible Date" in a FlexibleDateField as an integer with the format yyyymmdd. I render a form that includes a FlexibleDateField, and the value remains an integer so that functions necessary for validating it and rendering it in widgets work correctly. I call it in a template, as in {{ object.flexibledate }} and it is formatted according to the flexibledateformat rules: 20100416 - April 16, 2010; 20100400 - April 2010; 20100000 - 2010. This also applies when I'm not calling it directly, such as when it's used as a header in admin (http://example.org/admin/app_name/model_name/). I'm not aware if these specific things are possible.

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  • [Database] How to model this one-to-one relation?

    - by pbean
    I have several entities which respresent different types of users who need to be able to log in to a particular system. Additionally, they have different types of information associated with them. For example: a "general user", which has an e-mail address and "admin user", which has a workstation number (note that this a hypothetical case). Both entities also share common properties like first name, surname, address and telephone number. Finally, they naturally need to have a (unique) user name and a password to log in. In the application, the user just has to fill in his user name and password, and the functionality of the application changes slightly according to the type of the user. You can imagine that the username needs to be unique for this work. How should I model this effectively? I can't just create two tables, because then I can't force a unique constaint on the user name. I also can't put them all in just one table, because they have different types of specific information associated to them. I think I might need 3 seperate tables, one for "users" (with user name and password), one for the "general users" and another one for the "admin users", but how would the relations between these work? Or is there another solution? (By the way, the target DBMS is MySQL, so I don't think generalization is supported in the database system itself).

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  • How to do an additional search on archive in rails if record not found, by extending model?

    - by Nick Gorbikoff
    Hello, I was wondering if somebody knows an elegant solution to the following: Suppose I have a table that holds orders, with a bunch of data. So I'm at 1M records, and searches begin to take time. So I want to speed it up by archiving some data that is more than 3 years old - saving it into a table called orders-archive, and then purging them from the orders table. So if we need to research something or customer wants to pull older information - they still can, but 99% of the lookups are done on the orders no older than a year and a half - so there is no reason to keep looking through older data all the time. These move & purge operations can be then croned to be done on a weekly basis. I already did some tests and I know that I will slash my search times by about 4 times. So far so good, right? However I was thinking about how to implement older archival lookups and the only reasonable thing I can think of is some sort of if-else If not found in orders, do a search in orders-archive. However - I have about 20 tables that I want to archive and god knows how many searches / finds are done through out the code, that I don't want to modify. So I was wondering if there is an elegant rails-way solution to this problem, by extending a model somehow? Has anyone dealt with similar case before? Thank you.

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  • What do you call a generalized (non-GUI-related) "Model-View-Controller" architecture?

    - by dcuccia
    I am currently refactoring code that coordinates multiple hardware components for data acquisition, and feeling a bit like I'm recreating the wheel. In particular, an MVC-like pattern seems to be emerging. Except, this has nothing to do with a GUI and I'm worried that I'm forcing this particular pattern where another might be more appropriate. Here's my scenario: Individual hardware "component" classes obey interface contracts for each hardware type. Previously, component instances were orchestrated by a single monolithic InstrumentController class, which relied heavily on configuration + branching logic for executing a specific acquisition sequence. After an iteration, I have a separate controller for each component, with these controllers all managed by a small InstrumentControllerBase (or its derivatives). The composite system will receive "input" either programmatically or via inter-hardware component triggering - in either case these interactions are routed to, and handled by, the appropriate controller. So, I have something that feels MVC-esque, but I don't know if that's because I'm forcing the point. With little direct MVC experience in application development, it's hard to know if I'm just trying to make my scenario fit MVC, where another pattern might be a good alternative or complimentary. My problem is, search results and wiki documentation of these family of patterns seems to immediately drop me into GUI-specific discussions. I understand "M means Model data and the V means View" - but do you call the superset pattern? Component-Commander-Controller? Whence can I exhume examples exemplary?

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  • Data Modeling: Logical Modeling Exercise

    - by swisscheese
    In trying to learn the art of data storage I have been trying to take in as much solid information as possible. PerformanceDBA posted some really helpful tutorials/examples in the following posts among others: is my data normalized? and Relational table naming convention. I already asked a subset question of this model here. So to make sure I understood the concepts he presented and I have seen elsewhere I wanted to take things a step or two further and see if I am grasping the concepts. Hence the purpose of this post, which hopefully others can also learn from. Everything I present is conceptual to me and for learning rather than applying it in some production system. It would be cool to get some input from PerformanceDBA also since I used his models to get started, but I appreciate all input given from anyone. As I am new to databases and especially modeling I will be the first to admit that I may not always ask the right questions, explain my thoughts clearly, or use the right verbage due to lack of expertise on the subject. So please keep that in mind and feel free to steer me in the right direction if I head off track. If there is enough interest in this I would like to take this from the logical to physical phases to show the evolution of the process and share it here on Stack. I will keep this thread for the Logical Diagram though and start new one for the additional steps. For my understanding I will be building a MySQL DB in the end to run some tests and see if what I came up with actually works. Here is the list of things that I want to capture in this conceptual model. Edit for V1.2 The purpose of this is to list Bands, their members, and the Events that they will be appearing at, as well as offer music and other merchandise for sale Members will be able to match up with friends Members can write reviews on the Bands, their music, and their events. There can only be one review per member on a given item, although they can edit their reviews and history will be maintained. BandMembers will have the chance to write a single Comment on Reviews about the Band they are associated with. Collectively as a Band only one Comment is allowed per Review. Members can then rate all Reviews and Comments but only once per given instance Members can select their favorite Bands, music, Merchandise, and Events Bands, Songs, and Events will be categorized into the type of Genre that they are and then further subcategorized into a SubGenre if necessary. It is ok for a Band or Event to fall into more then one Genre/SubGenre combination. Event date, time, and location will be posted for a given band and members can show that they will be attending the Event. An Event can be comprised of more than one Band, and multiple Events can take place at a single location on the same day Every party will be tied to at least one address and address history shall be maintained. Each party could also be tied to more then one address at a time (i.e. billing, shipping, physical) There will be stored profiles for Bands, BandMembers, and general members. So there it is, maybe a bit involved but could be a great learning tool for many hopefully as the process evolves and input is given by the community. Any input? EDIT v1.1 In response to PerformanceDBA U.3) That means no merchandise other than Band merchandise in the database. Correct ? That was my original thought but you got me thinking. Maybe the site would want to sell its own merchandise or even other merchandise from the bands. Not sure a mod to make for that. Would it require an entire rework of the Catalog section or just the identifying relationship that exists with the Band? Attempted a mod to sell both complete albums or song. Either way they would both be in electronic format only available for download. That is why I listed an Album as being comprised of Songs rather then 2 separate entities. U.5) I understand what you bring up about the circular relation with Favorite. I would like to get to this “It is either one Entity with some form of differentiation (FavoriteType) which identifies its treatment” but how to is not clear to me. What am I missing here? u.6) “Business Rules This is probably the only area you are weak in.” Thanks for the honest response. I will readdress these but I hope to clear up some confusion in my head first with the responses I have posted back to you. Q.1) Yes I would like to have Accepted, Rejected, and Blocked. I am not sure what you are referring to as to how this would change the logical model? Q.2) A person does not have to be a User. They can exist only as a BandMember. Is that what you are asking? Minor Issue Zero, One, or More…Oops I admit I forgot to give this attention when building the model. I am submitting this version as is and will address in a future version. I need to read up more on Constraint Checking to make sure I am understanding things. M.4) Depends if you envision OrderPurchase in the future. Can you expand as to what you mean here? EDIT V1.2 In response to PerformanceDBA input... Lessons learned. I was mixing the concept of Identifying / Non-Identifying and Cardinality (i.e. Genre / SubGenre), and doing so inconsistently to make things worse. Associative Tables are not required in Logical Diagrams as their many-to-many relationships can be depicted and then expanded in the Physical Model. I was overlooking the Cardinality in a lot of the relationships The importance of reading through relationships using effective Verb Phrases to reassure I am modeling what I want to accomplish. U.2) In the concept of this model it is only required to track a Venue as a location for an Event. No further data needs to be collected. With that being said Events will take place on a given EventDate and will be hosted at a Venue. Venues will host multiple events and possibly multiple events on a given date. In my new model my thinking was that EventDate is already tied to Event . Therefore, Venue will not need a relationship with EventDate. The 5th and 6th bullets you have listed under U.2) leave me questioning my thinking though. Am I missing something here? U.3) Is it time to move the link between Item and Band up to Item and Party instead? With the current design I don't see a possibility to sell merchandise not tied to the band as you have brought up. U.5) I left as per your input rather than making it a discrete Supertype/Subtype Relationship as I don’t see a benefit of having that type of roll up. Additional Revisions AR.1) After going through the exercise for FavoriteItem, I feel that Item to Review requires a many-to-many relationship so that is indicated. Necessary? Ok here we go for v1.3 I took a few days on this version, going back and forth with my design. Once the logical process is complete, as I want to see if I am on the right track, I will go through in depth what I had learned and the troubles I faced as a beginner going through this process. The big point for this version was it took throwing in some Keys to help see what I was missing in the past. Going through the process of doing a matrix proved to be of great help also. Regardless of anything, if it wasn't for the input given by PerformanceDBA I would still be a lost soul wondering in the dark. Who knows my current design might reaffirm that I still am, but I have learned a lot so I am know I at least have a flashlight in my hand. At this point in time I admit that I am still confused about identifying and non-identifying relationships. In my model I had to use non-identifying relationships with non nulls just to join the relationships I wanted to model. In reading a lot on the subject there seems to be a lot of disagreement and indecisiveness on the subject so I did what I thought represented the right things in my model. When to force (identifying) and when to be free (non-identifying)? Anyone have inputs? EDIT V1.4 Ok took the V1.3 inputs and cleaned things up for this V1.4 Currently working on a V1.5 to include attributes.

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  • Is learning the Caché database hard coming from relational databases and object oriented programming

    - by Edelcom
    I am currently running the local version of Caché on my system in order to determine if I can (and will) take on a new possible project. The current project uses Delphi 7 as a front end calling a Caché dll where the business logic is stored in the database. I have a background of Sqlserver and Firebird (and before Access and Paradox) as databases. I use Delphi 7 for 95% of my Windows development, so I know about object programming. I would like to recieve opinions from persons having used Caché and either SqlServer, Firebird or Oracle and having developed in Delphi (or C++ or C# - an object oriented language). I have read the pro's and con's from other questions, but I am not asking for this, I need input from Caché developers. Thanks in advance.

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  • integrating tinymce with asp .net MVC 4.0

    - by user1865670
    using ASP .NET MVC 4.0 , VS2012. In one of my page, I tried to integrate a WYSIWYG editor "TinyMCE". To integrate, I followed the following URL : .tugberkugurlu.com My view page is like : @model AboutModels @using FileUploadDemo.Models <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.js"></script> <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script> <script src="Scripts/tinymce/jquery.tinymce.js" type="text/javascript"></script> @{ ViewBag.Title = "About"; } @using (Html.BeginForm()) { @Html.ValidationSummary(true) <fieldset> <legend>About</legend> <div class="editor-label"> @Html.LabelFor(model => model.Title) </div> <div class="editor-field"> @Html.EditorFor(model => model.Title) @Html.ValidationMessageFor(model => model.Title) </div> <div class="editor-label"> @Html.LabelFor(model => model.PostedOn) </div> <div class="editor-field"> @Html.EditorFor(model => model.PostedOn) @Html.ValidationMessageFor(model => model.PostedOn) </div> <div class="editor-label"> @Html.LabelFor(model => model.Tags) </div> <div class="editor-field"> @Html.EditorFor(model => model.Tags) @Html.ValidationMessageFor(model => model.Tags) </div> <div class="editor-label"> @Html.LabelFor(model => model.Content) </div> <div class="editor-field"> @Html.EditorFor(model => model.Content) @Html.ValidationMessageFor(model => model.Content) </div> <p> <input type="submit" value="Create" /> </p> <p> Posted Content : @ViewBag.HtmlContent </p> </fieldset> } Here my Model is like : public class AboutModels { public string Title { get; set; } public DateTime PostedOn { get; set; } public string Tags { get; set; } [UIHint("tinymce_jquery_full"), AllowHtml] public string Content { get; set; } } My about page loads with all features. "@html.EditorFor(model=>model.content)" also loads fine. but no "WYSIWYG" pane(i donno what it is called, the pane is used to edit my text written in the textarea(HTml.editorFor())) is loaded. In the runtime, Exception is thrown in jquery.tinymce.js file. Error Message : `Unhandled exception at line 86, column 11 in http://localhost:1706/Home/About 0x800a01b6 - Microsoft JScript runtime error: Object doesn't support this property or method` And give me two options, Continue or Break . If i continue, the page loads with features as i mentioned earlier. If i Break, then it stays in the jquery.tinymce.js file with a yellow text-background. I have no experience with Javascript/jquery. And new in ASP .NET MVC 4.0, actually this is my first try of web application in .net. I updated jquery from nuGet. What could be the possible ways to solve it?

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  • MySQL Relational Database Foreign Key

    - by user623879
    To learn databasing, I am creating a movie database. To associate multiple directors with a movie, I have the following schema: movie(m_ID, ....) m_director(dirID, dirName)//dirID is a autoincrement primary key m_directs(dirID, m_ID) //dirID, m_ID are set as foreign Keys in the mysql database(InnoDB engine) I have a program that connects to the db that needs to add a movie to the database. I can easily add a new entry to the movie table and the m_director table, but I am having trouble adding a entry in the m_directs table. INSERT INTO m_director (dirName) VALUES("Jason Reitman"); INSERT INTO m_directs (dirID, m_ID) VALUES(LAST_INSERT_ID(), "tt0467406"); I am using this sql statement to insert a new director and add the association to the movie. I know the primary key of the movie, but I don't know the dirID, so I use LAST_INSERT_ID() to get the last id of the director just inserted. The problem I am having is that I get the following error: MySql.Data.MySqlClient.MySqlException (0x80004005): Cannot add or update a child row: a foreign key constraint fails (`siteproducts`. `m_directs`, CONSTRAINT `m_directs_ibfk_2` FOREIGN KEY (`dirID`) REFERENCES `m_directs` (`dirID`) ON DELETE CASCADE ON UPDATE CASCADE) Any ideas?

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  • Pros/Cons of document based database vs relational database

    - by damian
    I've been trying to see if I can accomplish some requirements with a document based database, in this case CouchDB. Two generic requirements: CRUD of entities with some fields which have unique index on it ecommerce web app like eBay (better description here). And I'm begining to think that a Document-based database isn't the best choice to address these requirements. Furthermore, I can´t imagine a use for a Document based database (maybe my imagination is too little). Can you explain me if I am asking pears to an elm when I try to use a Document based database for this requirements?

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  • Example of an ASP.NET MVC post model?

    - by Anthony Potts
    I was watching the HaHaa presentation on ASP.NET MVC from MIX and they mentioned using a Post Model where I guess they were saying you could use a model that was ONLY for posting. I have tried looking for examples for this. Am I not understanding what they are saying? Does anyone have an example of how this might work in a strongly typed view where the view model and post model are not of the same type?

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  • Django User model, adding function

    - by Hellnar
    Hello, I want to add a new function to the default User model of Django for retrieveing a related list of Model type. Such Foo model: class Foo(models.Model): owner = models.ForeignKey(User, related_name="owner") likes = models.ForeignKey(User, related_name="likes") ........ #at some view user = request.user foos= user.get_related_foo_models() Hwo can this be achieved ?

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  • relational database: how to design this table

    - by donpal
    I'm a database newbie designing a database. I'll use SO to ask my question because it's easier to ask it on something that you can see already, but it's not the same, it will just help me understand the right approach. As you can see, there are many questions here and each can have many answers. How should I store the answers in a table? Should I store all the answers in the SAME table with a unique id (make it the key) and just a new field for the question id? What if there are 100,000 answers like there is here? Do I still store them in 1 table? What keys should I use to minimize search time when I want to search for the answers of a specific question? The database is both read and write if that makes any difference in this case.

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  • WPF - 'Relational' Data in XAML Using DataContext

    - by Andy T
    Hi, Say I have a list of Employee IDs from one data source and a separate data source with a list of Employees, with their ID, Surname, FirstName, etc. Is it possible in XAML only to get the Employee's name from the second data source and display it next to the ID, using something like this (with the syntax corrected)?.. <TextBlock x:Name="EmployeeID" Text="{Binding ID}"></TextBlock> <TextBlock Grid.Column="1" DataContext="{StaticResource EmployeeList[**where ID = {Binding ID}**]}" Text="{Binding Surname}"/> I'm thinking back to my days using XML and XSLT with XPath to achieve the kind of thing shown above. Is this kind of thing possible in XAML? Or do I need to 'denormalize' the data first in code, into one consolidated list? It seems like it should be possible to do this simple task using XAML only, but I can't quite get my head around how you would switch the DataContext correctly and what the syntax would be to achieve this. Is it possible, or am I barking up the wrong tree? Thanks, AT

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  • Options for keeping models and the UI in sync (in a desktop application context)

    - by Benju
    In my experience I have only had 2 patterns work for large-scale desktop application development when trying to keep the model and UI in sync. 1-An eventbus approach via a shared eventbus command objects are fired (ie:UserDemographicsUpdatedEvent) and have various parts of the UI update if they are bound to the same user object updated in this event. 2-Attempt to bind the UI directly to the model adding listeners to the model itself as needed. I find this approach rather clunky as it pollutes the domain model. Does anybody have other suggestions? In a web application with something like JSP binding to the model is easy as you ussually only care about the state of the model at the time your request comes in, not so in a desktop type application. Any ideas?

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  • Explanation of converting exporting an XML document as a relational database using XSLT

    - by Yaaqov
    I would like to better understand the basic steps needed to a take an XML document like this Breakfast Menu... <?xml version="1.0" encoding="ISO-8859-1"?> <breakfast_menu> <food> <name>Belgian Waffles</name> <price>$5.95</price> <description>two of our famous Belgian Waffles with plenty of real maple syrup</description> <calories>650</calories> </food> <food> <name>Strawberry Belgian Waffles</name> <price>$7.95</price> <description>light Belgian waffles covered with strawberries and whipped cream</description> <calories>900</calories> </food> <food> <name>Berry-Berry Belgian Waffles</name> <price>$8.95</price> <description>light Belgian waffles covered with an assortment of fresh berries and whipped cream</description> <calories>900</calories> </food> <food> <name>French Toast</name> <price>$4.50</price> <description>thick slices made from our homemade sourdough bread</description> <calories>600</calories> </food> <food> <name>Homestyle Breakfast</name> <price>$6.95</price> <description>two eggs, bacon or sausage, toast, and our ever-popular hash browns</description> <calories>950</calories> </food> </breakfast_menu> And "export" it to say, an Access or MySQL database using XSLT, creating two joined tables: Table: breakfast_menu Field: menu_item_id Field: food_id Table: food Field: food_id Field: name Field: price Field: description Field: calories If there are online tutorials on this that you know of, I'd be interesting in learning more, as well. Thanks.

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  • C#: Inheritance, Overriding, and Hiding

    - by Rosarch
    I'm having difficulty with an architectural decision for my C# XNA game. The basic entity in the world, such as a tree, zombie, or the player, is represented as a GameObject. Each GameObject is composed of at least a GameObjectController, GameObjectModel, and GameObjectView. These three are enough for simple entities, like inanimate trees or rocks. However, as I try to keep the functionality as factored out as possible, the inheritance begins to feel unwieldy. Syntactically, I'm not even sure how best to accomplish my goals. Here is the GameObjectController: public class GameObjectController { protected GameObjectModel model; protected GameObjectView view; public GameObjectController(GameObjectManager gameObjectManager) { this.gameObjectManager = gameObjectManager; model = new GameObjectModel(this); view = new GameObjectView(this); } public GameObjectManager GameObjectManager { get { return gameObjectManager; } } public virtual GameObjectView View { get { return view; } } public virtual GameObjectModel Model { get { return model; } } public virtual void Update(long tick) { } } I want to specify that each subclass of GameObjectController will have accessible at least a GameObjectView and GameObjectModel. If subclasses are fine using those classes, but perhaps are overriding for a more sophisticated Update() method, I don't want them to have to duplicate the code to produce those dependencies. So, the GameObjectController constructor sets those objects up. However, some objects do want to override the model and view. This is where the trouble comes in. Some objects need to fight, so they are CombatantGameObjects: public class CombatantGameObject : GameObjectController { protected new readonly CombatantGameModel model; public new virtual CombatantGameModel Model { get { return model; } } protected readonly CombatEngine combatEngine; public CombatantGameObject(GameObjectManager gameObjectManager, CombatEngine combatEngine) : base(gameObjectManager) { model = new CombatantGameModel(this); this.combatEngine = combatEngine; } public override void Update(long tick) { if (model.Health <= 0) { gameObjectManager.RemoveFromWorld(this); } base.Update(tick); } } Still pretty simple. Is my use of new to hide instance variables correct? Note that I'm assigning CombatantObjectController.model here, even though GameObjectController.Model was already set. And, combatants don't need any special view functionality, so they leave GameObjectController.View alone. Then I get down to the PlayerController, at which a bug is found. public class PlayerController : CombatantGameObject { private readonly IInputReader inputReader; private new readonly PlayerModel model; public new PlayerModel Model { get { return model; } } private float lastInventoryIndexAt; private float lastThrowAt; public PlayerController(GameObjectManager gameObjectManager, IInputReader inputReader, CombatEngine combatEngine) : base(gameObjectManager, combatEngine) { this.inputReader = inputReader; model = new PlayerModel(this); Model.Health = Constants.PLAYER_HEALTH; } public override void Update(long tick) { if (Model.Health <= 0) { gameObjectManager.RemoveFromWorld(this); for (int i = 0; i < 10; i++) { Debug.WriteLine("YOU DEAD SON!!!"); } return; } UpdateFromInput(tick); // .... } } The first time that this line is executed, I get a null reference exception: model.Body.ApplyImpulse(movementImpulse, model.Position); model.Position looks at model.Body, which is null. This is a function that initializes GameObjects before they are deployed into the world: public void Initialize(GameObjectController controller, IDictionary<string, string> data, WorldState worldState) { controller.View.read(data); controller.View.createSpriteAnimations(data, _assets); controller.Model.read(data); SetUpPhysics(controller, worldState, controller.Model.BoundingCircleRadius, Single.Parse(data["x"]), Single.Parse(data["y"]), bool.Parse(data["isBullet"])); } Every object is passed as a GameObjectController. Does that mean that if the object is really a PlayerController, controller.Model will refer to the base's GameObjectModel and not the PlayerController's overriden PlayerObjectModel? In response to rh: This means that now for a PlayerModel p, p.Model is not equivalent to ((CombatantGameObject)p).Model, and also not equivalent to ((GameObjectController)p).Model. That is exactly what I do not want. I want: PlayerController p; p.Model == ((CombatantGameObject)p).Model p.Model == ((GameObjectController)p).Model How can I do this? override?

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  • Replace textfields with dropdown select fields

    - by 47
    I have three model classes that look as below: class Model(models.Model): model = models.CharField(max_length=20, blank=False) manufacturer = models.ForeignKey(Manufacturer) date_added = models.DateField(default=datetime.today) def __unicode__(self): name = ''+str(self.manufacturer)+" "+str(self.model) return name class Series(models.Model): series = models.CharField(max_length=20, blank=True, null=True) model = models.ForeignKey(Model) date_added = models.DateField(default=datetime.today) def __unicode__(self): name = str(self.model)+" "+str(self.series) return name class Manufacturer(models.Model): MANUFACTURER_POPULARITY_CHOICES = ( ('1', 'Primary'), ('2', 'Secondary'), ('3', 'Tertiary'), ) manufacturer = models.CharField(max_length=15, blank=False) date_added = models.DateField(default=datetime.today) manufacturer_popularity = models.CharField(max_length=1, choices=MANUFACTURER_POPULARITY_CHOICES) def __unicode__(self): return self.manufacturer I want to have the fields for model series and manufacturer represented as dropdowns instead of text fields. I have customized the model forms as below: class SeriesForm(ModelForm): series = forms.ModelChoiceField(queryset=Series.objects.all()) class Meta: model = Series exclude = ('model', 'date_added',) class ModelForm(ModelForm): model = forms.ModelChoiceField(queryset=Model.objects.all()) class Meta: model = Model exclude = ('manufacturer', 'date_added',) class ManufacturerForm(ModelForm): manufacturer = forms.ModelChoiceField(queryset=Manufacturer.objects.all()) class Meta: model = Manufacturer exclude = ('date_added',) However, the dropdowns are populated with the unicode in the respective class...how can I further customize this to get the end result I want? Also, how can I populate the forms with the correct data for editing? Currently only SeriesForm is populated. The starting point of all this is from another class whose declaration is as below: class CommonVehicle(models.Model): year = models.ForeignKey(Year) series = models.ForeignKey(Series) .... def __unicode__(self): name = ''+str(self.year)+" "+str(self.series) return name

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