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  • Modelling class relations

    - by phenevo
    Hi, I have a few classes: Article ------- Content ID Magazine -------- Name Code And 3 tables in database: Articles Magazines ArticlesInMagazines (two fields: IDArticle and CodeMagazine) In my app, I've got a module to manage Articles, and a datagridview to relate their associated magazines DataGridView has twofields: MagazineCode IsPublished (indicates articles which have been published in this magazine). The same article can be in many magazines (1:n) How would you implement on model ? Article have to has a field : List ?? I am concerned because Magazine associates Articles

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  • Hibernate and parent/child relations

    - by Marco
    Hi to all, I'm using Hibernate in a Java application, and i feel that something could be done better for the management of parent/child relationships. I've a complex set of entities, that have some kind of relationships between them (one-to-many, many-to-many, one-to-one, both unidirectional and bidirectional). Every time an entity is saved and it has a parent, to estabilish the relationship the parent has to add the child to its collection (considering a one-to-may relationship). For example: Parent p = (Parent) session.load(Parent.class, pid); Child c = new Child(); c.setParent(p); p.getChildren().add(c); session.save(c); session.flush(); In the same way, if i remove a child then i have to explicitly remove it from the parent collection too. Child c = (Child) session.load(Child.class, cid); session.delete(c); Parent p = (Parent) session.load(Parent.class, pid); p.getChildren().remove(c); session.flush(); I was wondering if there are some best practices out there to do this jobs in a different way: when i save a child entity, automatically add it to the parent collection. If i remove a child, automatically update the parent collection by removing the child, etc. For example, Child c = new Child(); c.setParent(p); session.save(c); // Automatically update the parent collection session.flush(); or Child c = (Child) session.load(Child.class, cid); session.delete(c); // Automatically updates its parents (could be more than one) session.flush(); Anyway, it would not be difficult to implement this behaviour, but i was wondering if exist some standard tools or well known libraries that deals with this issue. And, if not, what are the reasons? Thanks

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  • Tables as relations in ER diagrams

    - by Richard Mar.
    Assume I have the following tables (**bold** - primary key, *italics* - foreign key): patient(**patient_id**, name) disease(**disease_id**, name) patient_disease(**p_d_id**, *patient_id*, *disease,_id* ) I want to draw the ER diagram for this. My idea is to make two entities, one for patient and one for disease, then make a n-to-n relation between them, with p_d_id as its attribute. Is that how it's supposed to be?

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  • Formtastic with Mongoid embedded_in relations

    - by miah
    Is there any quick way to make a form for embeds_many-embedded_in relation? I have the following: class Team include Mongoid::Document field :name, :type => String embeds_many :players end class Player include Mongoid::Document embedded_in :team, :inverse_of => :players field :name, :type => String end I want to create a form for team with embedded editing for players. Seen https://github.com/bowsersenior/formtastic_with_mongoid_tutorial but "TODO" there.

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  • how to query with child relations to same table and order this correctly

    - by robertpnl
    Hi, Take this table: id name sub_id --------------------------- 1 A (null) 2 B (null) 3 A2 1 4 A3 1 The sub_id column is a relation to his owm table, to column ID. subid --- 0:1 --- id Now I have the problem to make a correctly SELECT query to show that the child rows (which sub_id is not null) directly selected under his parent row. So this must be a correctly order: 1 A (null) 3 A2 1 4 A3 1 2 B (null) A normal SELECT order the id. But how or which keyword help me to order this correctly? JOIN isn't possible I think because I want to get all the rows seperated. Because the rows will be displayed on a Gridview (ASP.Net) with EntityDataSource but the child rows must be displayed directly under his parent. Thank you.

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  • MATLAB: Automatic detection of relations between workspace variables through functions

    - by Peterstone
    Hi all, I´m trying to write a function what detect this relation between the variables I have got in the workspace: v1 - fft(v2) = 0 Where v1, v2 are variables of my workspace. Sometimes I need to know which variables have a certain numerical relation. If I have thirty, I don´t want to be looking for this relation in "manual way", just itroducing a sentence for each pair of different variables. I would like a function in which I introuce (or I modify this function every time I need it) the sentence (for instance what I wrote before) and the function show me the pair of variables a I am looking for. Does anyone know how to do it? Thank you so much!

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  • Help with active record relations

    - by Christian Fazzini
    class CreateActivities < ActiveRecord::Migration def self.up create_table :activities do |t| t.references :user t.references :media t.integer :artist_id t.string :type t.timestamps end end def self.down drop_table :activities end end class Fan < Activity belongs_to :user, :counter_cache => true end class Activity < ActiveRecord::Base belongs_to :user belongs_to :media belongs_to :artist, :class_name => 'User', :foreign_key => 'artist_id' end class User < ActiveRecord::Base has_many :activities has_many :fans end I tried changing my activity model too, without any success: class Activity < ActiveRecord::Base has_many :activities, :class_name => 'User', :foreign_key => 'user_id' has_many :activities, :class_name => 'User', :foreign_key => 'artist_id' end One thing to note. Activity is an STI. Fan inherits from Activity. In console, I do: # Create a fan object. User is a fan of himself fan = Fan.new => #<Fan id: nil, user_id: nil, media_id: nil, artist_id: nil, type: "Fan", comment: nil, created_at: nil, updated_at: nil> # Assign a user object fan.user = User.first => #<User id: 1, genre_id: 1, country_id: 1, .... # Assign an artist object fan.artist_id = User.first.id => 1 # Save the fan object fan.save! => true Activity.last => #<Fan id: 13, user_id: 1, media_id: nil, artist_id: 1, type: "Fan", comment: nil, created_at: "2010-12-30 08:41:25", updated_at: "2010-12-30 08:41:25"> Activity.last.user => #<User id: 1, genre_id: 1, country_id: 1, ..... But... Activity.last.artist => nil Why is Activity.last.artist returning nil?

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  • Rails: Design Pattern to Store Order of Relations

    - by ChrisInCambo
    Hi, I have four models: Customer, QueueRed, QueueBlue, QueueGreen. The Queue models have a one to many relationship with customers A customer must always be in a queue A customer can only be in one queue at a time A customer can change queues We must be able to find out the customers current position in their respective queue In an object model the queues would just have an array property containing customers, but ActiveRecord doesn't have arrays. In a DB I would probably create some extra tables just to handle the order of the stories in the queue. My question is what it the best way to model the relationship in ActiveRecord? Obviously there are many ways this could be done, but what is the best or the most in line with how ActiveRecord should be used? Cheers, Chris

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  • Confusions with CSS and JavaScript relations ?

    - by Anil Namde
    I have table cell which has class "cellActive". Which has following defination .cellActive{background:"#DDDDDD"} Now i am trying to read the background color property for the cell and it comes null/"". var bgColor = cell.style.backgroundColor; // returning "" Is that something mistake on my part of its by behavior. If CSS class is assigning CSS to element can't we read its value in JS ? Does this mean that if we are not assigning property directly to the element we cant get it if in case its inheriting it ?

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  • CSS and JavaScript relations ?

    - by Anil Namde
    I have table cell which has class "cellActive". Which has following defination .cellActive{background:"#DDDDDD"} Now i am trying to read the background color property for the cell and it comes null/"". var bgColor = cell.style.backgroundColor; // returning "" Is that something mistake on my part of its by behavior. If CSS class is assigning CSS to element can't we read its value in JS ? Does this mean that if we are not assigning property directly to the element we cant get it if in case its inheriting it ?

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  • Enable export to XML via HTTP on a large number of models with child relations

    - by Vasil
    I've a large number of models (120+) and I would like to let users of my application export all of the data from them in XML format. I looked at django-piston, but I would like to do this with minimum code. Basically I'd like to have something like this: GET /export/applabel/ModelName/ Would stream all instances of ModelName in applabel together with it's tree of related objects . I'd like to do this without writing code for each model. What would be the best way to do this?

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  • Django: remove all m2m relations

    - by pistacchio
    Hi, if I have two simple models: class Tag(models.Model): name = models.CharField(max_length=100) class Post(models.Model): title = models.CharField(max_length=100) tags = models.ManyToManyField(Tag, blank=True) given a Post object with a number of Tags added to it, I know hot to remove any of them, but how to do a mass remove (remove all)? Thanks

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  • How to solve recursion relations in mathematica efficiently?

    - by Qiang Li
    I have a recursion to solve for. f(m,n)=Sum[f[m - 1, n - 1 - i] + f[m - 3, n - 5 - i], {i, 2, n - 2*m + 2}] + f[m - 1, n - 3] + f[m - 3, n - 7] f(0,n)=1, f(1,n)=n However, the following mma code is very inefficient f[m_, n_] := Module[{}, If[m < 0, Return[0];]; If[m == 0, Return[1];]; If[m == 1, Return[n];]; Return[Sum[f[m - 1, n - 1 - i] + f[m - 3, n - 5 - i], {i, 2, n - 2*m + 2}] + f[m - 1, n - 3] + f[m - 3, n - 7]];] It takes unbearably long to compute f[40,20]. Could anyone please suggest an efficient way of doing this? Many thanks!

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  • doctrine default values and relations

    - by Skirmantas
    Concept: Lets say we have table Properties with columns id and name (lets say with some predefined values: "Good" "Better" "Best"). Another table Users has column property_id with many to one relation on Properties (property_id = id). Users has default value on property_id, lets say 1 which means "Good". We might have another table analogue to Users however with default property, lets say "Better". What I need is ability to change default value for Users or other tables in administrator's panel. In mysql I can set default value for column like this: ALTER TABLE <Table> CHANGE <Column> DEFAULT <NEW_DEFAULT_VALUE> I can retrieve default value: SELECT DEFAULT(<Column>) FROM <Table> LIMIT 1 Is it possible to achieve this concept with Doctrine? What I actually need is such method in my table class: class UserTable extend Doctrine_Table { /* ... */ getDefaultProperty() { } setDefaultProperty($value) { /* $value can be either integer or Doctrine_Record */ } }

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  • A better understanding of the relations beetween database tables

    - by Nistor Alexandru
    Hi I am trying to get a better understanding of relational databases and there is something that I keep bumping into and don't understand.Let's take this two tables: In this case Login.ID is the primary key with auto_increment set and Profile.ID_LOGIN is the Foreign KEY.When a user is created and it's username and password is stored in the login database does the ID coresponding to the curesnt username and password get automaticly added into ID_LOGIN or do I have to create an SQL statement to do this? If I have to create a SQL statement how should I aproach adding the ID_LOGIN to make sure I am adding it corectly?

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  • Dynamic class_name for has_many relations

    - by vooD
    I'm trying to make has_many relation with dynamic class_name attribute class Category < ActiveRecord::Base has_many :ads, :class_name => ( lambda { return self.item_type } ) end or class Category < ActiveRecord::Base has_many :ads, :class_name => self.item_type end But i got errors: can't convert Proc into String or undefined method `item_type' for #<Class:0xb62c6c88> Thank you for any help!

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  • Trying to make models in Kohana, relations problem.

    - by Asaf
    I have a table of Hits, Articles and Categories Now, a Hit belongs_to an Article/Category (depends on where it was done). so I have a column on Hits table with the name 'parenttype' That tells me 'Article' or 'Category'. I wrote in the Hit model (extends ORM) protected $_belongs_to= array( 'page' => array('model'=> $this->parenttype) ); Now it complains about $this-parenttype not being expected?

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  • dist-upgrade runs and completes but current kernel stays the same

    - by jaguare22
    I think that my system is staying at an older kernel version. It seems to update when I run dist-upgrade but the current kernel version doesn't change. Is it possible the system is set to install new kernel updates but only load an older version at start up? $ uname -a Linux HTPC 3.2.0-32-generic #51-Ubuntu SMP Wed Sep 26 21:32:50 UTC 2012 i686 athlon i386 GNU/Linux $ dpkg --list | grep linux-image ii linux-image-3.2.0-32-generic 3.2.0-32.51 Linux kernel image for version 3.2.0 on 32 bit x86 SMP ii linux-image-3.2.0-32-generic-pae 3.2.0-32.51 Linux kernel image for version 3.2.0 on 32 bit x86 SMP ii linux-image-3.2.0-32-virtual 3.2.0-32.51 Linux kernel image for version 3.2.0 on 32 bit x86 Virtual Guests dpkg -l 'linux-*' | sed '/^ii/!d;/'"$(uname -r | sed "s/\(.*\)-\([^0-9]\+\)/\1/")"'/d;s/^[^ ]* [^ ]* \([^ ]*\).*/\1/;/[0-9]/!d' linux-headers-3.2.0-36 linux-headers-3.2.0-36-generic-pae linux-headers-3.2.0-37 linux-headers-3.2.0-37-generic-pae linux-headers-3.2.0-38 linux-headers-3.2.0-38-generic-pae linux-headers-3.2.0-39 linux-headers-3.2.0-39-generic-pae linux-headers-3.2.0-40 linux-headers-3.2.0-40-generic-pae linux-headers-3.2.0-41 linux-headers-3.2.0-41-generic-pae linux-headers-3.2.0-43 linux-headers-3.2.0-43-generic-pae linux-headers-3.2.0-44 linux-headers-3.2.0-44-generic-pae linux-headers-3.2.0-45 linux-headers-3.2.0-45-generic-pae linux-headers-3.2.0-48 linux-headers-3.2.0-48-generic-pae

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  • Generic Sorting using C# and Lambda Expression

    - by Haitham Khedre
    Download : GenericSortTester.zip I worked in this class from long time and I think it is a nice piece of code that I need to share , it might help other people searching for the same concept. this will help you to sort any collection easily without needing to write special code for each data type , however if you need special ordering you still can do it , leave a comment and I will see if I need to write another article to cover the other cases. I attached also a fully working example to make you able to see how do you will use that .     public static class GenericSorter { public static IOrderedEnumerable<T> Sort<T>(IEnumerable<T> toSort, Dictionary<string, SortingOrder> sortOptions) { IOrderedEnumerable<T> orderedList = null; foreach (KeyValuePair<string, SortingOrder> entry in sortOptions) { if (orderedList != null) { if (entry.Value == SortingOrder.Ascending) { orderedList = orderedList.ApplyOrder<T>(entry.Key, "ThenBy"); } else { orderedList = orderedList.ApplyOrder<T>(entry.Key,"ThenByDescending"); } } else { if (entry.Value == SortingOrder.Ascending) { orderedList = toSort.ApplyOrder<T>(entry.Key, "OrderBy"); } else { orderedList = toSort.ApplyOrder<T>(entry.Key, "OrderByDescending"); } } } return orderedList; } private static IOrderedEnumerable<T> ApplyOrder<T> (this IEnumerable<T> source, string property, string methodName) { ParameterExpression param = Expression.Parameter(typeof(T), "x"); Expression expr = param; foreach (string prop in property.Split('.')) { expr = Expression.PropertyOrField(expr, prop); } Type delegateType = typeof(Func<,>).MakeGenericType(typeof(T), expr.Type); LambdaExpression lambda = Expression.Lambda(delegateType, expr, param); MethodInfo mi = typeof(Enumerable).GetMethods().Single( method => method.Name == methodName && method.IsGenericMethodDefinition && method.GetGenericArguments().Length == 2 && method.GetParameters().Length == 2) .MakeGenericMethod(typeof(T), expr.Type); return (IOrderedEnumerable<T>)mi.Invoke (null, new object[] { source, lambda.Compile() }); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }

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  • how to concatenate two strings in shell script in 3.13.0-34-generic kernel

    - by saikrishna
    I want to concatenate two strings for the shell file im getting error when i have created the shell file in following manner could you please suggest how to get it set export APP_HOME="/home/sfptladmin/ArchivalDaemon" export JAVA_HOME="/usr/lib/jvm/java-7-oracle/jre" export LIBPATH="/home/sfptladmin/ArchivalDaemon/lib" export CPATH=$APP_HOME/conf export CPATH=$CPATH:$LIBPATH/commons-beanutils-core-1.7.0.jar export CPATH=$CPATH:$LIBPATH/commons-collections-3.2.jar export CPATH=$CPATH:$LIBPATH/commons-io-1.4.jar export CPATH=$CPATH:$LIBPATH/commons-lang.jar export CPATH=$CPATH:$LIBPATH/commons-net.jar export CPATH=$CPATH:$LIBPATH/dataloader-27.0.1-uber.jar export CPATH=$CPATH:$LIBPATH/dom4j-1.6.1.jar export CPATH=$CPATH:$LIBPATH/log4j-1.2.15.jar export CPATH=$CPATH:$LIBPATH/opencsv2.3.jar export CPATH=$CPATH:$LIBPATH/poi-3.7.jar export CPATH=$CPATH:$LIBPATH/poi-ooxml-3.7.jar export CPATH=$CPATH:$LIBPATH/poi-ooxml-schemas-3.7.jar export CPATH=$CPATH:$LIBPATH/wsc-23-min.jar export CPATH=$CPATH:$LIBPATH/xmlbeans-2.5.0.jar export CPATH=$CPATH:$LIBPATH/archival-daemon-main.jar export CPATH=$CPATH:$LIBPATH/sbmclasspath.jar export CPATH=$CPATH java -Xms256m -Xmx512m -classpath $CPATH "-Dfile.encoding=UTF-8" com.genpact.proflow.daemon.archival.manager.ArchivalManager echo $CPATH

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  • Generic log analyzer that produces reports

    - by Eugene
    About 600 customers use our application. We have very detailed logs for everything that happens in the application, from changes in the data model, memory and CPU/GPU usage to clicks on the UI elements. We want to be able to parse the logs coming from these customers and analyze them to understand how users use our application and what happens internally in the application. Is there a log analyzer that can produce such reports automatically?

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  • Some More New ADF Features in JDeveloper 11.1.2

    - by Steven Davelaar
    The official list of new features in JDeveloper 11.1.2 is documented here. While playing with JDeveloper 11.1.2 and scanning the web user interface developer's guide for 11.1.2, I noticed some additional new features in ADF Faces, small but might come in handy:  You can use the af:formatString and af:formatNamed constructs in EL expressions to use substituation variables. For example: <af:outputText value="#{af:formatString('The current user is: {0}',someBean.currentUser)}"/> See section 3.5.2 in web user interface guide for more info. A new ADF Faces Client Behavior tag: af:checkUncommittedDataBehavior. See section 20.3 in web user interface guide for more info. For this tag to work, you also need to set the  uncommittedDataWarning  property on the af:document tag. And this property has quite some issues as you can read here. I did a quick test, the alert is shown for a button that is on the same page, however, if you have a menu in a shell page with dynamic regions, then clicking on another menu item does not raise the alert if you have pending changes in the currently displayed region. For now, the JHeadstart implementation of pending changes still seems the best choice (will blog about that soon). New properties on the af:document tag: smallIconSource creates a so-called favicon that is displayed in front of the URL in the browser address bar. The largeIconSource property specifies the icon used by a mobile device when bookmarking the page to the home page. See section 9.2.5 in web user interface guide for more info. Also notice the failedConnectionText property which I didn't know but was already available in JDeveloper 11.1.1.4. The af:showDetail tag has a new property handleDisclosure which you can set to client for faster rendering. In JDeveloper 11.1.1.x, an expression like #{bindings.JobId.inputValue} would return the internal list index number when JobId was a list binding. To get the actual JobId attribute value, you needed to use #{bindings.JobId.attributeValue}. In JDeveloper 11.1.2 this is no longer needed, the #{bindings.JobId.inputValue} expression will return the attribute value corresponding with the selected index in the choice list. Did you discover other "hidden" new features? Please add them as comment to this blog post so everybody can benefit. 

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  • Designing generic render/graphics component in C++?

    - by s73v3r
    I'm trying to learn more about Component Entity systems. So I decided to write a Tetris clone. I'm using the "style" of component-entity system where the Entity is just a bag of Components, the Components are just data, a Node is a set of Components needed to accomplish something, and a System is a set of methods that operates on a Node. All of my components inherit from a basic IComponent interface. I'm trying to figure out how to design the Render/Graphics/Drawable Components. Originally, I was going to use SFML, and everything was going to be good. However, as this is an experimental system, I got the idea of being able to change out the render library at will. I thought that since the Rendering would be fairly componentized, this should be doable. However, I'm having problems figuring out how I would design a common Interface for the different types of Render Components. Should I be using C++ Template types? It seems that having the RenderComponent somehow return it's own mesh/sprite/whatever to the RenderSystem would be the simplest, but would be difficult to generalize. However, letting the RenderComponent just hold on to data about what it would render would make it hard to re-use this component for different renderable objects (background, falling piece, field of already fallen blocks, etc). I realize this is fairly over-engineered for a regular Tetris clone, but I'm trying to learn about component entity systems and making interchangeable components. It's just that rendering seems to be the hardest to split out for me.

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