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  • Relationships via Email Rather Than User List

    - by Bob Lerner
    I'm new at Drupal, so I may have missed a solution despite a lot of research: I want users to be able to invite non-users and other users into a named relationship they've set up (using e.g. the Friendlist or User Relationships module) using only email addresses and not the user list. I believe that invitations from both of those modules are done only after the inviter selects the invitee after selecting the invitee from a list of all users. Frankly, I would be surprised if no email solution exists since a large site's user list would be daunting. Does anyone know if this is possible using Organic Groups? Thanks very much.

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  • Other link relationships and impact to the SEO

    - by haha
    Example other link relationships <head> <link rel='index' title='Main Title' href='http://domain.com/' /> <link rel='start' title='Part Three' href='http://domain.com/part-3/' /> <link rel='prev' title='Part Two' href='http://domain.com/part-2/' /> <link rel='next' title='Part Four' href='http://domain.com/part-4/' /> </head> Questions Have a big impact to make my site get a nice rank to Search Engine?

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  • Representing parent-child relationships in SharePoint lists

    - by Chris Farmer
    I need to create some functionality in our SharePoint app that populates a list or lists with some simple hierarchical data. Each parent record will represent a "submission" and each child record will be a "submission item." There's a 1-to-n relationship between submissions and submission items. Is this practical to do in SharePoint? The only types of list relationships I've done so far are lookup columns, but this seems a bit different. Also, once such a list relationship is established, then what's the best way to create views on this kind of data. I'm almost convinced that it'd be easier just to write this stuff to an external database, but I'd like to give SharePoint a shot in order to take advantage of the automated search capabilities.

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  • Chaining Many-To-Many Dimensional Relationships in SSAS

    - by Ray Saltrelli
    I'm developing a cube in SSAS and attempting to model the following relationships: Many Facts to 1 Customer Many Customers to Many Sales Reps Many Sales Reps (Subordinates) to Sales Reps (Managers) Each M2M relationship is facilitated by a bridge table which also acts as a fact table in the cube I have most of this working. I can slice Facts by Customer and by Sales Rep (Subordinate), but when I add Sales Rep (Manager) to the query it appears to return every subordinate/manager combination regardless of whether or not that relationship exists in the bridge table. Any ideas as to what I might be doing wrong?

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  • IndexedDB and Relationships

    - by Josh Johnson
    Can I create relationships between my object stores in IndexedDB? For example, I have two object stores: artist and album. An artist has a one-to-many relationship with an album. album.artistId relates the album to artist.id. I'm thinking along the lines of Hibernate here. I would like to do a query for artists and have the albums belonging to that artist returned as an array called artists on the album object. artist.albums = [];

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  • LINQ to Entites: Doing a count over one-to-many relationships

    - by chris
    I have a couple of tables where there are one to many relationships. Let's say I have a Country table, a State table with a FK to Country, and a City table with a FK to State. I'd like to be able to create a count of all Cities for a given country, and also a count of cities based on a filter - something like: foreach( var country in Model.Country ) { total = country.State.All().City.All().Count() ; filtered = country.State.All().City.Any(c=>c.field == value).Count(); } Obviously, this doesn't work - is there any way to do this?

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  • Entity Framework 4 and 0:1, 0:1 relationships

    - by Eric J.
    I'm using the Model First approach with EF 4 and hit a snag with two tables, Participant (singular because pre-existing from another app) and ActiveParticipants. A Participant may or may not be associated with exactly one ActiveParticipant and vice versa. When I create an association, everything seems to go well on the surface, but then I get a runtime error complaining that Participant does not contain the column ActiveParticipant_Id. It does contain a column ActiveParticipantId (no underscore). When I view the diagram as XML, there's a line like this: <Property Name="ActiveParticipant_Id" Type="uniqueidentifier" Nullable="true" /> Why is it adding an underscore? Is there anything special I need to do for 0:1, 0:1 relationships?

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  • Computed Column with relationships

    - by Sethery
    I have a table, MapLocation, which has a column and two relationships with tables that have a field that really need to be displayed as a single concatenated value. I was thinking this was a perfect case for a computed column, but not sure how to go about it. MapLocation MaoNo Section _____________________ _____________________ _____________________ MapNoId MapNoId SectionId SectionId MapNumber (int) Section (int) Identifier (nvarchar) LocationName (nvarchar) LocationName = "MapNUmber - SectionNumber - Identifier" ex: 20 - 03 - SW4 How would I write that? I haven't done much with computed columns or concatenating in SQL. Edit: I need an actual computed column that is automatically updated, im looking for the formula. Or is this more of a function/trigger? Its possible, I certainly barely know what I'm doing. The idea is that I dont want to have to do two more server calls and concatenate these values client side.

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  • Problem building relationships between models

    - by Brian Roisentul
    Until now, I've been using acts_as_taggable_on plugin for tagging announcements. That plugin creates the following tables: taggings: relates tags and announcements table(for the tagged item, it has a field called taggable_id, which I rename to "announcement_id" for what I'll explain below). tags: has the tag ids and names. The other day, I discovered that I had no way of getting the announcements tagged with a certain tag, but doing Announcement.tagged_with(tag_name), and I don't want to search by name, but for id. So, as I'm using almost nothing of the functionality in that plugin, I decided to create the models for taggings and tags tables, to accomplish this: Announcement.tags. The models' relationships look as following: class Tagging < ActiveRecord::Base belongs_to :announcement belongs_to :tag end class Tag < ActiveRecord::Base has_many :announcements, :through => :taggings end class Announcement < ActiveRecord::Base has_many :tags, :through => :taggings Why can't I execute the command Announcement.tags? Because when I try, I get undefined method `tags'

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  • C#: How to resolve this circular dependency?

    - by Rosarch
    I have a circular dependency in my code, and I'm not sure how to resolve it. I am developing a game. A NPC has three components, responsible for thinking, sensing, and acting. These components need access to the NPC controller to get access to its model, but the controller needs these components to do anything. Thus, both take each other as arguments in their constructors. ISenseNPC sense = new DefaultSenseNPC(controller, worldQueryEngine); IThinkNPC think = new DefaultThinkNPC(sense); IActNPC act = new DefaultActNPC(combatEngine, sense, controller); controller = new ControllerNPC(act, think); (The above example has the parameter simplified a bit.) Without act and think, controller can't do anything, so I don't want to allow it to be initialized without them. The reverse is basically true as well. What should I do? ControllerNPC using think and act to update its state in the world: public class ControllerNPC { // ... public override void Update(long tick) { // ... act.UpdateFromBehavior(CurrentBehavior, tick); CurrentBehavior = think.TransitionState(CurrentBehavior, tick); } // ... } DefaultSenseNPC using controller to determine if it's colliding with anything: public class DefaultSenseNPC { // ... public bool IsCollidingWithTarget() { return worldQuery.IsColliding(controller, model.Target); } // ... }

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  • Circular Dependencies in XML file

    - by user3006081
    my android xml layout file keeps on Exception raised during rendering: Circular dependencies cannot exist in RelativeLayout Exception details are logged in Window Show View Error Log I cant figure out why? here is my code <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.amandhapola.ribbit.LoginActivity" android:background="@drawable/background_fill" > <ImageView android:id="@+id/backgroundImage" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_alignParentLeft="true" android:layout_alignParentTop="true" android:scaleType="fitStart" android:src="@drawable/background" android:contentDescription="@string/content_desc_background"/> <TextView android:id="@+id/title" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_above="@+id/subtitle" android:layout_centerHorizontal="true" android:textSize="60sp" android:layout_marginTop="32dp" android:textColor="@android:color/white" android:textStyle="bold" android:text="@string/app_name" /> <TextView android:id="@+id/subtitle" android:layout_centerHorizontal="true" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/title" android:layout_above="@+id/usernameField" android:textSize="13sp" android:textColor="@android:color/white" android:textStyle="bold" android:text="@string/subtitle"/> <EditText android:id="@+id/usernameField" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_above="@+id/passwordField" android:layout_below="@+id/subtitle" android:layout_alignParentLeft="true" android:ems="10" android:hint="@string/username_hint" /> <EditText android:id="@+id/passwordField" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/usernameField" android:layout_above="@+id/loginButton" android:layout_alignParentLeft="true" android:layout_marginBottom="43dp" android:ems="10" android:hint="@string/password_hint" android:inputType="textPassword" /> <Button android:id="@+id/loginButton" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/passwordField" android:layout_above="@+id/signUpText" android:layout_alignParentLeft="true" android:text="@string/login_button_label" /> <TextView android:id="@+id/signUpText" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="12dp" android:layout_centerHorizontal="true" android:textColor="@android:color/white" android:layout_below="@+id/loginButton" android:text="@string/sign_up_text" /> </RelativeLayout>

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  • Circular dependecy in winforms app using Castle Windsor

    - by Sven
    Hello, I was experimenting a little bit with Castle winforms in a winforms project. I wanted to register all my form dependencies with Castle windsor. This way I would have a single instance for all my forms. Now I have some problem though. I'm in a situation that form x has a dependency on form y and form y has a dependency on form x. Practical example maybe: form x is used to create an order, form y is the screen that has a list of customers. From form x there is a button to select a customer for the order. This will open form y where ou can search the customer. There is a button that lets you add the found customer to the order. It will call a method on form x and passes the selected customer object. I could do this with events. Raise an event in form y and listen for that in form x. But isn't there a way around the circular dependency in Castle Windsor, lazy registration or something? Can anyone help me out? Thanks in advance

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  • jCarousel - achieving an active state AND wrap:circular

    - by swisstony
    Hey folks A while back I implemented the jCarousel image solution for a client that required a numbered active state. After a bit of googling a found the answer but noticed that the preferred circular option would not work. What would happen is that once the carousel had cycled through all its (5) images, upon the return to the first, the active state would be lost, because, according to jcarousel it was actually the 6th (the index just keeps on incrementing). I just went ahead and instead used wrap:'both' which at least had a correctly functioning active state. However now the client says they dont like this effect and simply want the animation to return to position 1 after the final image. This means I need to get'wrap: 'both' working somehow. Below is my current code. Can someone please solve this one, as its a little above my head! function highlight(carousel, obejctli,liindex,listate){ jQuery('.jcarousel-control a:nth-child('+ liindex +')').attr("class","active"); }; function removehighlight(carousel, obejctli,liindex,listate){ jQuery('.jcarousel-control a:nth-child('+ liindex +')').removeAttr("class","active"); }; jQuery('#mycarousel').jcarousel({ initCallback: mycarousel_initCallback, auto: 5, wrap: 'both', vertical: true, scroll: 1, buttonNextHTML: null, buttonPrevHTML: null, animation: 1000, itemVisibleInCallback: highlight, itemVisibleOutCallback: removehighlight }); }); Thanks in advance

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  • Json.Net Issues: StackOverflowException is thrown when serialising circular dependent ISerializable object with ReferenceLoopHandling.Ignore

    - by keyr
    I have a legacy application that used binary serialisation to persist the data. Now we wanted to use Json.net 4.5 to serialise the data without much changes to the existing classes. Things were working nice till we hit a circular dependent class. Is there any workaround to solve this problem? Sample code as shown below [Serializable] class Department : ISerializable { public Employee Manager { get; set; } public string Name { get; set; } public Department() { } public Department( SerializationInfo info, StreamingContext context ) { Manager = ( Employee )info.GetValue( "Manager", typeof( Employee ) ); Name = ( string )info.GetValue( "Name", typeof( string ) ); } public void GetObjectData( SerializationInfo info, StreamingContext context ) { info.AddValue( "Manager", Manager ); info.AddValue( "Name", Name ); } } [Serializable] class Employee : ISerializable { [NonSerialized] //This does not work [XmlIgnore]//This does not work private Department mDepartment; public Department Department { get { return mDepartment; } set { mDepartment = value; } } public string Name { get; set; } public Employee() { } public Employee( SerializationInfo info, StreamingContext context ) { Department = ( Department )info.GetValue( "Department", typeof( Department ) ); Name = ( string )info.GetValue( "Name", typeof( string ) ); } public void GetObjectData( SerializationInfo info, StreamingContext context ) { info.AddValue( "Department", Department ); info.AddValue( "Name", Name ); } } And the test code Department department = new Department(); department.Name = "Dept1"; Employee emp1 = new Employee { Name = "Emp1", Department = department }; department.Manager = emp1; Employee emp2 = new Employee() { Name = "Emp2", Department = department }; IList<Employee> employees = new List<Employee>(); employees.Add( emp1 ); employees.Add( emp2 ); var memoryStream = new MemoryStream(); var formatter = new BinaryFormatter(); formatter.Serialize( memoryStream, employees ); memoryStream.Seek( 0, SeekOrigin.Begin ); IList<Employee> deserialisedEmployees = formatter.Deserialize( memoryStream ) as IList<Employee>; //Works nicely JsonSerializerSettings jsonSS= new JsonSerializerSettings(); jsonSS.TypeNameHandling = TypeNameHandling.Objects; jsonSS.TypeNameAssemblyFormat = FormatterAssemblyStyle.Full; jsonSS.Formatting = Formatting.Indented; jsonSS.ReferenceLoopHandling = ReferenceLoopHandling.Ignore; //This is not working!! //jsonSS.ReferenceLoopHandling = ReferenceLoopHandling.Serialize; //This is also not working!! jsonSS.PreserveReferencesHandling = PreserveReferencesHandling.All; string jsonAll = JsonConvert.SerializeObject( employees, jsonSS ); //Throws stackoverflow exception Edit1: The issue has been reported to Json (http://json.codeplex.com/workitem/23668)

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  • Ternary (and n-ary) relationships in Hibernate

    - by Bytecode Ninja
    Q 1) How can we model a ternary relationship using Hibernate? For example, how can we model the ternary relationship presented here using Hibernate (or JPA)? Ideally I prefer my model to be like this: class SaleAssistant { Long id; //... } class Customer { Long id; //... } class Product { Long id; //... } class Sale { SalesAssistant soldBy; Customer buyer; Product product; //... } Q 1.1) How can we model this variation, in which each Sale item might have many Products? class SaleAssistant { Long id; //... } class Customer { Long id; //... } class Product { Long id; //... } class Sale { SalesAssistant soldBy; Customer buyer; Set<Product> products; //... } Q 2) In general, how can we model n-ary, n = 3 relationships with Hibernate? Thanks in advance.

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  • Modeling multiple polymorphic relationships using Hibernate

    - by f-potter
    Ruby on Rails has polymorphic relations which are really useful for implementing functionality such as commenting, tagging and rating to name a few. We can have a comment, tag or rating class which has a many to one polymorphic relationship with a commentable, taggable and rateable object. Also, a given domain object can choose to implement any combination of such relations. So, it can for example be commentable, taggable and rateable at the same time. I couldn't think up of a straightforward way to duplicate this functionality in Hibernate. Ideally, there would be a Comment class which will have a many to one relationship with a Commentable class and a Commentable class will conversely have a one to many relationship with Comments. It will be ideal if the concrete domain classes can inherit from a number of such classes, say Commentable and Taggable. Things seem a little complicated as a Java class can only extend one other class and some code might end up being duplicated across a number of classes. I wanted to know what are the best practices for modeling such relationships neatly and concisely using Hibernate?

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  • How to setup relationships in contact Database

    - by Walt
    I am currently embarking on a new venture to learn PHP and MySQL. I have done some simple databases in the past using Access, but this one is to be a web-centric database for tracking a myriad of data including contacts and project information. I will need to link the various tables in various relationships, and I am not sure the best way to do that. Since I am just starting out with PHP/MySQL I am researching online sources for learning as much as possible. If anyone has recommendations on books or websites, I would appreciate it. In setting up my tables, one major area that I am concerned with is contacts. I will have a variety of contacts that include: employees, clients, vendors, subcontractors, etc.. and a single contact can be multiple types and each type would have various additional fields that pertain to them. My thought was to have one contacts table that links to other tables for the various contact types. I'm not sure which field type or setup of table options are best... Thoughts? This scenario will likely play out in other areas of the database as well for projects and products. Any pointers/direction would be appreciated. WES

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  • How to properly set relationships in Core Data when using setValue and data already exists

    - by ern
    Let's say I have two objects: Articles and Categories. For the sake of this example all relevant categories have already been added to the data store. When looping through data that holds edits for articles, there is category relationship information that needs to be saved. I was planning on using the -setValue method in the Article class in order to set the relationships like so: - (void)setValue:(id)value forUndefinedKey:(NSString *)key { if([key isEqualToString:@"categories"]){ NSLog(@"trying to set categories..."); } } The problem is that value isn't a Category, it is just a string (or array of strings) holding the title of a category. I could certainly do a lookup within this method for each category and assign it, but that seems inefficient when processing a whole bunch of articles at once. Another option is to populate an array of all possible categories and just filter, but my question is where to store that array? Should it be a class method on Article? Is there a way to pass in additional data to the -setValue method? Is there another, better option for setting the relationship I'm not thinking of? Thanks for your help.

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  • Managing Many to Many relationships in asp.net Wizard Control

    - by Luis
    Say I have this entity with a lot of attributes. In the input form I have decided to implement a wizard control so I can collect information about this entity in several steps. The problem is that I need to collect information that has been modeled has many to many relationships. I am planning to use a telerik gridview to manage this (add/edit/delete), the problem is where do I store that data since the entity in a insert form is not created on the database yet. OK so I can store all that info in temporary lists residing in the viewstate, waiting for the final submit where I dump all that in the DB, but one of the steps I am collecting files...now storing files in the viewstate is out of the question, same as as storing them in the session... I have been thinking of implementing in a way that the user has to submit some info first (say first 3 steps), commit the data to the database creating the parent entity and then start inserting all the childs entities...but this will get weird as it's confusing since on the first steps you not saving the data to the DB and on the next ones you are commiting directly... Anyone has any thoughts on this? Thanks

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  • Crop circular or elliptical image from original UIImage

    - by vikas ojha
    I am working on openCV for detecting the face .I want face to get cropped once its detected.Till now I got the face and have marked the rect/ellipse around it on iPhone. Please help me out in cropping the face in circular/elliptical pattern (UIImage *) opencvFaceDetect:(UIImage *)originalImage { cvSetErrMode(CV_ErrModeParent); IplImage *image = [self CreateIplImageFromUIImage:originalImage]; // Scaling down /* Creates IPL image (header and data) ----------------cvCreateImage CVAPI(IplImage*) cvCreateImage( CvSize size, int depth, int channels ); */ IplImage *small_image = cvCreateImage(cvSize(image->width/2,image->height/2), IPL_DEPTH_8U, 3); /*SMOOTHES DOWN THYE GUASSIAN SURFACE--------:cvPyrDown*/ cvPyrDown(image, small_image, CV_GAUSSIAN_5x5); int scale = 2; // Load XML NSString *path = [[NSBundle mainBundle] pathForResource:@"haarcascade_frontalface_default" ofType:@"xml"]; CvHaarClassifierCascade* cascade = (CvHaarClassifierCascade*)cvLoad([path cStringUsingEncoding:NSASCIIStringEncoding], NULL, NULL, NULL); // Check whether the cascade has loaded successfully. Else report and error and quit if( !cascade ) { NSLog(@"ERROR: Could not load classifier cascade\n"); //return; } //Allocate the Memory storage CvMemStorage* storage = cvCreateMemStorage(0); // Clear the memory storage which was used before cvClearMemStorage( storage ); CGColorSpaceRef colorSpace; CGContextRef contextRef; CGRect face_rect; // Find whether the cascade is loaded, to find the faces. If yes, then: if( cascade ) { CvSeq* faces = cvHaarDetectObjects(small_image, cascade, storage, 1.1f, 3, 0, cvSize(20, 20)); cvReleaseImage(&small_image); // Create canvas to show the results CGImageRef imageRef = originalImage.CGImage; colorSpace = CGColorSpaceCreateDeviceRGB(); contextRef = CGBitmapContextCreate(NULL, originalImage.size.width, originalImage.size.height, 8, originalImage.size.width * 4, colorSpace, kCGImageAlphaPremultipliedLast|kCGBitmapByteOrderDefault); //VIKAS CGContextDrawImage(contextRef, CGRectMake(0, 0, originalImage.size.width, originalImage.size.height), imageRef); CGContextSetLineWidth(contextRef, 4); CGContextSetRGBStrokeColor(contextRef, 1.0, 1.0, 1.0, 0.5); // Draw results on the iamge:Draw all components of face in the form of small rectangles // Loop the number of faces found. for(int i = 0; i < faces->total; i++) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; // Calc the rect of faces // Create a new rectangle for drawing the face CvRect cvrect = *(CvRect*)cvGetSeqElem(faces, i); // CGRect face_rect = CGContextConvertRectToDeviceSpace(contextRef, // CGRectMake(cvrect.x * scale, cvrect.y * scale, cvrect.width * scale, cvrect.height * scale)); face_rect = CGContextConvertRectToDeviceSpace(contextRef, CGRectMake(cvrect.x*scale, cvrect.y , cvrect.width*scale , cvrect.height*scale*1.25 )); facedetectapp=(FaceDetectAppDelegate *)[[UIApplication sharedApplication]delegate]; facedetectapp.grabcropcoordrect=face_rect; NSLog(@" FACE off %f %f %f %f",facedetectapp.grabcropcoordrect.origin.x,facedetectapp.grabcropcoordrect.origin.y,facedetectapp.grabcropcoordrect.size.width,facedetectapp.grabcropcoordrect.size.height); CGContextStrokeRect(contextRef, face_rect); //CGContextFillEllipseInRect(contextRef,face_rect); CGContextStrokeEllipseInRect(contextRef,face_rect); [pool release]; } } CGImageRef imageRef = CGImageCreateWithImageInRect([originalImage CGImage],face_rect); UIImage *returnImage = [UIImage imageWithCGImage:imageRef]; CGImageRelease(imageRef); CGContextRelease(contextRef); CGColorSpaceRelease(colorSpace); cvReleaseMemStorage(&storage); cvReleaseHaarClassifierCascade(&cascade); return returnImage; } } Thanks Vikas

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  • derby + hibernate ConstraintViolationException using manytomany relationships

    - by user364470
    Hi, I'm new to Hibernate+Derby... I've seen this issue mentioned throughout the google, but have not seen a proper resolution. This following code works fine with mysql, but when I try this on derby i get exceptions: ( each Tag has two sets of files and vise-versa - manytomany) Tags.java @Entity @Table(name="TAGS") public class Tags implements Serializable { @Id @GeneratedValue(strategy=GenerationType.AUTO) public long getId() { return id; } @ManyToMany(targetEntity=Files.class ) @ForeignKey(name="USER_TAGS_FILES",inverseName="USER_FILES_TAGS") @JoinTable(name="USERTAGS_FILES", joinColumns=@JoinColumn(name="TAGS_ID"), inverseJoinColumns=@JoinColumn(name="FILES_ID")) public Set<data.Files> getUserFiles() { return userFiles; } @ManyToMany(mappedBy="autoTags", targetEntity=data.Files.class) public Set<data.Files> getAutoFiles() { return autoFiles; } Files.java @Entity @Table(name="FILES") public class Files implements Serializable { @Id @GeneratedValue(strategy=GenerationType.AUTO) public long getId() { return id; } @ManyToMany(mappedBy="userFiles", targetEntity=data.Tags.class) public Set getUserTags() { return userTags; } @ManyToMany(targetEntity=Tags.class ) @ForeignKey(name="AUTO_FILES_TAGS",inverseName="AUTO_TAGS_FILES") @JoinTable(name="AUTOTAGS_FILES", joinColumns=@JoinColumn(name="FILES_ID"), inverseJoinColumns=@JoinColumn(name="TAGS_ID")) public Set getAutoTags() { return autoTags; } I add some data to the DB, but when running over Derby these exception turn up (the don't using mysql) Exceptions SEVERE: DELETE on table 'FILES' caused a violation of foreign key constraint 'USER_FILES_TAGS' for key (3). The statement has been rolled back. Jun 10, 2010 9:49:52 AM org.hibernate.event.def.AbstractFlushingEventListener performExecutions SEVERE: Could not synchronize database state with session org.hibernate.exception.ConstraintViolationException: could not delete: [data.Files#3] at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:96) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:2712) at org.hibernate.persister.entity.AbstractEntityPersister.delete(AbstractEntityPersister.java:2895) at org.hibernate.action.EntityDeleteAction.execute(EntityDeleteAction.java:97) at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:268) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:260) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:184) at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321) at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:51) at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1206) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:613) at org.hibernate.context.ThreadLocalSessionContext$TransactionProtectionWrapper.invoke(ThreadLocalSessionContext.java:344) at $Proxy13.flush(Unknown Source) at data.HibernateORM.removeFile(HibernateORM.java:285) at data.DataImp.removeFile(DataImp.java:195) at booting.DemoBootForTestUntilTestClassesExist.main(DemoBootForTestUntilTestClassesExist.java:62) I have never used derby before so maybe there is something crutal that i'm missing 1) what am I doing wrong? 2) is there any way of cascading properly when I have 2 many-to-many relationships between two classes? Thanks!

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  • How common are circular references? Would reference-counting GC work just fine?

    - by user9521
    How common are circular references? The less common they are, the fewer hard cases you have if you are writing in a language with only reference counting-GC. Are there any cases where it wouldn't work well to make one of the references a "weak" reference so that reference counting still works? It seems like you should be able to have a language only use reference counting and weak references and have things work just fine most of the time, with the goal of efficiency. You could also have tools to help you detect memory leaks caused by circular references. Thoughts, anyone? It seems that Python uses references counting (I don't know if it uses a tracing collector occasionally or not for sure) and I know that Vala uses reference counting with weak references; I know that it's been done before, but how well would it work?

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  • How to avoid circular dependencies between Player and World?

    - by futlib
    I'm working on a 2D game where you can move up, down, left and right. I have essentially two game logic objects: Player: Has a position relative to the world World: Draws the map and the player So far, World depends on Player (i.e. has a reference to it), needing its position to figure out where to draw the player character, and which portion of the map to draw. Now I want to add collision detection to make it impossible for the player to move through walls. The simplest way I can think of is to have the Player ask the World if the intended movement is possible. But that would introduce a circular dependency between Player and World (i.e. each holds a reference to the other), which seems worth avoiding. The only way I came up with is to have the World move the Player, but I find that somewhat unintuitive. What is my best option? Or is avoiding a circular dependency not worth it?

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  • Implementing Unowned relationship Google App Engine

    - by nwallman
    My question is more of a best practices question on how to implement unowned relationships with Google App Engine. I am using JDO to do my persistence and like recommended in the google docs I'm persisting my list of unowned relationships like so: @PersistenceCapable(identityType = IdentityType.APPLICATION) public class User implements Serializable, UserDetails { ... @Persistent private List<Key> groups; ... } Now I came across my predicament when I went to query that list of objects using they Key object. So when I get my list of group keys in order to actually return a list of Group objects I have to do a look up on that key to get the object. My question is what is the recommended way of doing a unowned look up on a model object? Should I have an instance of the PersistanceManagerFactory on my Model object so I can do a lookup? Should I have an instance of my GroupDAO object on my Model object so I can do a look up? Should I have a Utility to do this type of lookup? I'm new to this so I just want to know which is the best way to do this. Thanks.

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  • Nullable One To One Relationships with Integer Keys in LINQ-to-SQL

    - by Craig Walker
    I have two objects (Foo and Bar) that have a one-to-zero-or-one relationship between them. So, Foo has a nullable foreign key reference to Bar.ID and a (nullbusted) unique index to enforce the "1" side. Bar.ID is an int, and so Foo.BarID is a nullable int. The problem occurs in the LINQ-to-SQL DBML mapping of .NET types to SQL datatypes. Since int is not a nullable type in .NET, it gets wrapped in a Nullable<int>. However, this is not the same type as int, and so Visual Studio gives me this error message when I try to create the OneToOne Association between them: Cannot create an association "Bar_Foo". Properties do not have matching types: "ID", "BarID". Is there a way around this?

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