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  • Rails Nested Attributes, Relationship for Shared or Common Object

    - by SooDesuNe
    This has to be a common problem, so I'm surprised that Google didn't turn up more answers. I'm working on a rails app that has several different kinds of entities, those entities by need a relation to a different entity. For example: Address: a Model that stores the details of a street address (this is my shared entity) PersonContact: a Model that includes things like home phone, cell phone and email address. This model needs to have an address associated with it DogContact: Obviously, if you want to contact a dog, you have to go to where it lives. So, PersonContact and DogContact should have foreign keys to Address. Even, though they are really the "owning" object of Address. This would be fine, except that accepts_nested_attributes_for is counting on the foreign key being in Address to work correctly. What's the correct strategy to keep the foreign key in Address, but have PersonContact and DogContact be the owning objects?

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  • Search filenames in MySQL database table restricted by filetype?

    - by ju
    Hello I have a MySQL database that I replicate from another server. The database contains a table with this columns ID, FileName and FileSize In the table there are more than 4'000'000 records. I want to make fast a search in FileName (varchar) column I found that I can use for this Sphinx search engine. The problem is that I want to restrict searches by filetype. Do I have to and how (trigers?) to extract file extensions for all rows? May be I have to create another table (because this one is replicated) and join them in 1:1 relation? Can you give me some advices please :)

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  • Can someone please explain to me the basic function of Intents in the Android OS?

    - by K-RAN
    I'm new to programming applications for the Android OS. As far as general architecture of the OS goes, I understand that processes are implemented as Linux processes and that each one is sandboxed. However, I'm utterly confused on the IPCs and syscalls (if any) used. I know that the IBinder is a form of this; parcels are sent back and forth between processes and Bundles are array forms of parcels (?). But even that is still unfamiliar to me. Same with Intents. All in all, I don't understand what kinds of IPCs are implemented and how. Could someone briefly explain to me the specific methods used by user level applications in Android OS to communicate with each other and the OS? I've done kernel programming and played with various IPCs in Linux (Ubuntu and Debian) so it would help immensely if this was all explained in relation to what I'm familiar with... Thanks in advance!

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  • Best Dijkstra papers to explain this quote?

    - by jemfinch
    I was enjoying "The Humble Programmer" earlier today and ran across this choice quote: Therefore, for the time being and perhaps forever, the rules of the second kind present themselves as elements of discipline required from the programmer. Some of the rules I have in mind are so clear that they can be taught and that there never needs to be an argument as to whether a given program violates them or not. Examples are the requirements that no loop should be written down without providing a proof for termination nor without stating the relation whose invariance will not be destroyed by the execution of the repeatable statement. I'm looking for which of Dijkstra's 1300+ writings best describe in further detail rules such as he was describing above.

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  • django getting current user id

    - by dana
    hello, i have a mini app where users can login, view their profile, and follow each other. 'Follow' is a relation like a regular 'friend' relationship in virtual communities, but it is not necessarily reciprocal, meaning that one can follow a user, without the need that the user to be following back that person who follows him. my problem is: if i am a logged in user, and i navigate to a profile X, and push the button follow, how can i take the current profile id ?(current profile meaning the profile that I, the logged in user, am viewing right now.) the view: def follow(request): if request.method == 'POST': form = FollowForm(request.POST) if form.is_valid(): new_obj = form.save(commit=False) new_obj.initiated_by = request.user u = User.objects. what here? new_obj.follow = u new_obj.save() return HttpResponseRedirect('.') else: form = FollowForm() return render_to_response('followme/follow.html', { 'form': form, }, context_instance=RequestContext(request)) thanks in advance!

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  • Exception while trying to deserialize JSON into EntityFramework using JavaScriptSerializer

    - by Barak
    I'm trying to deserialize JSON which I'm getting from an external source into an Entity Framework entity class using the following code: var serializer = new JavaScriptSerializer(); IList<Feature> obj = serializer.Deserialize<IList<Feature>>(json); The following exception is thrown: Object of type 'System.Collections.Generic.List1[JustTime.Task]' cannot be converted to type 'System.Data.Objects.DataClasses.EntityCollection1[JustTime.Task]'. My model is simple: The Feature class has a one-to-many relation to the Tasks class. The problem appears to be the deserializer is trying to create a generic List to hold the collection of tasks instead of an EntityCollection. I've tried implementing a JavaScriptConverted which would handle System.Collections.Generic.List but it didn't get called by the deserializer.

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  • Is it possible to listen to relational database update?

    - by Morgan Cheng
    Is it possible to listen to relation database update? For example, my web app want to send data update to client through Comet technology. I can have the program to poll the database periodically, but that would not be performant and scalable. If app can hood to a "event handler" of database, then app can get notification every time given database table data is updated. This sounds more promising, but I didn't find any concrete example for it. This is listener pattern. Does common relational database support such feature?

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  • Entity Framework 4 code-only reference column name

    - by Victor
    I created classes: public class Country { public long CountryId {get;set;} public string CountryName {get;set;} } public class Profile { public long ProfileId {get;set;} public string ProfileName {get;set;} public Country Country {get;set;} } and configuration for Profile: public class ProfileConfiguration : EntityConfiguration<Profile> { public IlluminatiCoreProfileConfiguration() { Relation(p => p.Country); } } Then I create context and run context.CreateDatabase(). New database contains table Profiles with column Country_CountryId. How can I write configuration for changing column name to "CountryId"? Thanks.

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  • Upgrade Oracle database from 9.2.0.7 to 9.2.0.8

    - by b_dws
    We are planning to upgrade from Oracle 9.2.0.7 to 9.2.0.8. Main reason of the proposed upgrade is to address the issue in relation to exception "terminated with error: ORA-00904: "T2"."SYS_DS_ALIAS_4": invalid identifier" when we try to execute DBMS_STATS.GATHER_SCHEMA_STATS. We are concerned that the proposed upgrade may have negative impact on our Java application or in the worst case may not even support by our Java application. What are the possible approaches or strategies that we can take to ensure the upgrade from Oracle 9.2.0.7 to 9.2.0.8 will not have adverse impact on our Java application or will not cause our Java application to function incorrectly. Essentially we just want to confirm that our application will still support Oracle 9.2.0.8. Thank you.

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  • Dynamic table in Asp.Net

    - by Sivakumar
    Hi guys here I've created d dynamic table and how can i set d properties of the table like height, width and etc? Pls help me.. Thanks... code private void GenerateTable(int rowsCount) { Table table = new Table(); for (int i = 0; i < rowsCount; i++) { TableRow row = new TableRow(); TableCell cell = new TableCell(); TextBox tb1 = new TextBox(); DropDownList drp1 = new DropDownList(); tb1.ID= "dname"+i;drp1.ID = "relation" + i; cell.Controls.Add(tb1); cell.Controls.Add(drp1); row.Cells.Add(cell);table.Rows.Add(row); } rowsCount++; ViewState["RowsCount"] = rowsCount; }

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  • Best way to order menu items injected by an IoC/plugin Framework

    - by Daver
    One of the common things I've seen done in applications built on IoC/plugin frameworks is to add commands to menus or toolbars from the dynamically loaded plugins. For example, the application's default plugins supply actions like "New, Open, Save" that show up in the context menu for a certain item in the workspace. A new plugin may add "Mail, Post, Encrypt" commands, but where do those commands show up in relation to "New, Open, Save"? How can the application that is loading components through IoC impose order on the items that get injected? Does it require metadata from the plugins that give a hint on how to group or order the items? Does it use a config file of previously known menu names (or ids) to define the order (seems a little weak to me)? Or are "unknown" plugins treated as second class citizens and always get dumped into sub menus? Something I've never even imagined (which I'm hoping to see in the answers)

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  • Should I use Enumeration or Class stereotype in UML to represent a type directory table?

    - by Ivan
    Let's take 2 UML class model entities: One represents an actual Order and another represents an Orede Type. Any Order corresponds to one Type. A 2-way-naviglabe many Orders to one Type relation is meant. Order Type instances are, for example, "Request availability", "Request price", "Preorder", "Buy", "Cancel", "Request support", etc. Order Types are to be addable and editable in the resulting application. Should I model Order Type as Class or as Enumeration? From the data perspective I can't see the difference actually.

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  • SQL timetable for employee

    - by latinunit-net
    Hi guys, i need to create an employee shift database. so i have 3 tables so far, employee, employee_shift, and shift im suppose to calculate how many shifts an employee has done at the end of the month, my question means, because a month has 30 days some have 28 and 31 days. this means i need to create in the shift table 31 different variations? one for each day of the month? in order to calculate which employee has worked the most? in my business relation it says an employee has either 1 or 2 shifts per day therefore do i have to have 60 different rows of variations? im i right or is there an easy way to work it out

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  • Too Many Left Outer Joins in Entity Framework 4?

    - by Adam
    I have a product entity, which has 0 or 1 "BestSeller" entities. For some reason when I say: db.Products.OrderBy(p = p.BestSeller.rating).ToList(); the SQL I get has an "extra" outer join (below). And if I add on a second 0 or 1 relation ship, and order by both, then I get 4 outer joins. It seems like each such entity is producing 2 outer joins rather than one. LINQ to SQL behaves exactly as you'd expect, with no extra join. Has anyone else experienced this, or know how to fix it? SELECT [Extent1].[id] AS [id], [Extent1].[ProductName] AS [ProductName] FROM [dbo].[Products] AS [Extent1] LEFT OUTER JOIN [dbo].[BestSeller] AS [Extent2] ON [Extent1].[id] = [Extent2].[id] LEFT OUTER JOIN [dbo].[BestSeller] AS [Extent3] ON [Extent2].[id] = [Extent3].[id] ORDER BY [Extent3].[rating] ASC

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  • Query a column and a calculation of columns at the same time PostgreSQL

    - by pablo
    Hi I have two tables, Products and BundleProducts that have o2o relation with BaseProducts. A BundleProduct is a collection of Products using a m2m realtion to the Products table. Products has a price column and the price of a BundleProduct is calculated as the sum of the prices of its Products. BaseProducts have columns like name and description so I can query it to get both Products and BundleProducts. Is it possible to query and sort by price both for the price column of the Products and calculated price of the BundleProducts? Thanks

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  • java protected method accessibility

    - by JavaUser
    In the below code the Consumer class can access the protected method of Parent class.How is it possible since there is no relation between Parent and Consumer class.Please explain class Parent { public void method1(){ System.out.println("PUBLIC METHOD"); } private void method2(){ System.out.println("PRIVATE METHOD"); } protected void method3(){ System.out.println("PROTECTED METHOD"); } } public class Consumer { public static void main(String[] args){ Parent parentObj = new Parent(); parentObj.method1(); //parentObj.method2(); parentObj.method3(); } } Thanks

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  • Store data in file system rather than SQL or Oracle database.

    - by nunu
    Hi All, As I am working on Employee Management system, I have two table (for example) in database as given below. EmployeeMaster (DB table structure) EmployeeID (PK) | EmployeeName | City MonthMaster (DB table structure) Month | Year | EmployeeID (FK) | PrenentDays | BasicSalary Now my question is, I want to store data in file system rather than storing data in SQL or ORACLE. I want my data in file system storage for Insert, Edit and Delete opration with keeping relation with objects too. I am a C# developer, Could anybody have thoughts or idea on it. (To store data in file system with keeping relations between them) Thanks in advance. Any ideas on it?

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  • Android: Constructing a triangle based on Geographical information

    - by Aidan
    Hi Guys, I'm constructing a geolocation based application and I'm trying to figure out a way to make my application realise when a user is facing the direction of the given location (a particular long / lat co-ord). I've got the math figured, I just have the triangle to construct. Here's a further clarification of what I want to do.. I just want to know is there a way to get java to construct 2 other co-ordinates based on my orientation in relation to true north and my current co-ordinate? I'd like to construct a tri-angle, 45 degrees out each way of my current location (one of the points) and 1 kilometer in that direction. The problem is I don't know how to make Android/Java recognise that I want to find that point in the direction I'm currently facing.. Anyone got any ideas?

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  • Multiple foreign keys from one table linking to single primary key in second table

    - by croker10
    Hi all, I have a database with three tables, a household table, an adults table and a users table. The Household table contains two foreign keys, iAdult1ID and iAdult2ID. The Users table has a iUserID primary key and the Adult table has a corresponding iUserID foreign key. One of the columns in the Users table is strUsername, an e-mail address. I am trying to write a query that will allow me to search for an e-mail address for either adult that has a relation to the household. So I have two questions, assuming that all the values are not null, how can I do this? And two, in reality, iAdult2ID can be null, is it still possible to write a query to do this? Thanks for your help. Let me know if you need any more information.

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  • what is the best and valid way for cross browser min-height?

    - by metal-gear-solid
    for #main-content I don't want to give any fix height because content can be long and short but if content is short then it should take minimum height 500px. i need compatibility in all browser. Is thery any w3c valid and cross browser way without using !important because i read !important should not be used In conclusion, don’t use the !important declaration unless you’ve tried everything else first, and keep in mind any drawbacks. If you do use it, it would probably make sense, if possible, to put a comment in your CSS next to any styles that are being overridden, to ensure better code maintainability. I tried to cover everything significant in relation to use of the !important declaration, so please offer comments if you think there’s anything I’ve missed, or if I’ve misstated anything, and I’ll be happy to make any needed corrections. http://www.impressivewebs.com/everything-you-need-to-know-about-the-important-css-declaration/

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  • django many to many validation when add()

    - by Julien
    Hi i have a Category model with parent/child self relation For primary category and sub categories : class Place(models.Model): name = models.CharField(_("name"), max_length=100) categories = models.ManyToManyField("Category", verbose_name=_("categories")) class Category(models.Model): name = models.CharField(_("name"), max_length=100) parent = models.ForeignKey('self', blank=True, null=True, related_name='child_set') i need to prevent orphans, to prevent this kind of errors (in admin web interface) c_parent = Category(name='Restaurant') c_parent.save() c_child = Category(name="Japanese restaurant", parent=c_parent) c_child.save() place1 = Place (name="Planet sushi") place1.save() place1.categories.add(c_parent) place1.categories.add(c_child) So now we have a new Place called "Planet sushi", it's a Restaurant (root category), and a Japanese Restaurant (sub category) but i want to prevent this kind of things : place2 = Place (name="Tokyofood") place2.save() place2.categories.add(c_child) because parent is not set, or is not the correct parent category where can i do form validation for the admin ? and other forms (because any user can add a new place and will have to choose correct categories for)

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  • C doubt regarding array of pointers please explain

    - by ramya
    why do we use static with array of pointers?what is the relation betwwen static and array of pointers??plz help.... for eg: main() { int a[]={1,2,3}; int *p[]={a,a+1,a+2}; ...... } this code shows illegal initialization.why?whereas the following code works main() { static int a[]={1,2,3}; static int *p[]={a,a+1,a+2}; ...... } please do clear my doubt as soon as possible....

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  • sqlite - Foreign keys in VS2008 Designer

    - by rene marxis
    Hello I'm starting over to use strong typed datasets in VS 2008 with sqlite and running into a problem. I have some tables that have foreign keys allready defined in the database. I can see those in the Server-Explorer. Now i create a new strong typed Dataset with the designer and add only one table from that realtion to the dataset. Then i like to add the second one and i get an error message "Unexpected error ... Source: Microsoft.VSDesigner; ErrorCode:-1" No Additional Info. The error does not occure if i add both tables at the same time (say i drag them from the serverexplorer). Is there any way to add subsequent tables to an dataset that are in relation(s) to alreay added once? Many thanks _rene

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  • Empty dict-like collection problem in SQLAlchemy

    - by maksymko
    I have a mapping in SQLAlchemy that looks like this: t_property_value = sa.Table('property_value', MetaData, autoload = True, autoload_with = engine) orm.mapper(PropertyValue, t_property_value) t_estate = sa.Table('estate', MetaData, autoload = True, autoload_with = engine) orm.mapper(Estate, t_estate, properties = dict( property_hash = orm.relation(PropertyValue, collection_class = column_mapped_collection(t_property_value.c.property_id)) )) Now, everything seems to be fine, when I load the Estate object and it has some relations to PropertyValue objects. However, when it does not, then property_hash attribute is None, instead of being something dict-like, so I can not add new relations like this: estate.property_hash[prop_id] = PropertyValue(...) because I get the "'NoneType' object does not support item assignment" error. So, is there any way to force SQLAlchemy to create proper empty collection?

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  • Help me refactor this nasty Ruby if/else statement

    - by Suborx
    Hello, so I have this big method in my application for newsletter distribution. Method is for updating rayons and I need to assign a user to rayon. I have relation n:n through table colporteur_in_rayons which has attributes since_date and until_date. I am a junior programmer and I know this code is pretty dummy :) I appreciate every suggestion. def update rayon = Rayon.find(params[:id]) if rayon.update_attributes(params[:rayon]) if params[:user_id] != "" unless rayon.users.empty? unless rayon.users.last.id.eql?(params[:user_id]) rayon.colporteur_in_rayons.last.update_attributes(:until_date => Time.now) Rayon.assign_user(rayon.id,params[:user_id]) flash[:success] = "Rayon #{rayon.name} has been succesuly assigned to #{rayon.actual_user.name}." return redirect_to rayons_path end else Rayon.assign_user(rayon.id,params[:user_id]) flash[:success] = "Rayon #{rayon.name} has been successfully assigned to #{rayon.actual_user.name}." return redirect_to rayons_path end end flash[:success] = "Rayon has been successfully updated." return redirect_to rayons_path else flash[:error] = "Rayon has not been updated." return redirect_to :back end end

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