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Search found 1068 results on 43 pages for 'relation'.

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  • Rails3 nomethod error #<ActiveRecord::Relation>

    - by Dodi
    Hi! I'm writing a static page controller. I get the menuname in the routes.rb and it's call the static controller show method. match '/:menuname' = 'static#show' And static_controller.rb: @static=Staticpage.where("menuname = ?", params[:menuname]) But if I want print @static.title in the view, I get this error: undefined method `title' for # Whats wrong? the SQL query looks good: SELECT staticpages.* FROM staticpages WHERE (menuname = 'asd')

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  • How to initialize list with parent child relation

    - by user2917702
    Let's say I have the following classes. public class Parent { public string name; IList<Children> children; } public class Child { public string parentName; public int age; } As it is understandable, each parent can have multiple children, and we can have multiple parents. What is the best way to initialize these classes? Is it better to get all of the parents, and all of the children from database then use LINQ? IList<Parent> parents = GetParents()//assume this gets parents from db IList<Child> children = GetChildren() //assume this gets children from db foreach(Parent parent in parents) { parent.children = children.Where(x=>x.parentName==parent.name).ToList(); } or get all of the parents and iterate through each parent to query database by parentName to get children information? Due to requirement that I have, I cannot use datatable or dataset; I can only use datareader. IList<Parent> parents = GetParents()//assume this gets parents from db foreach(Parent parent in parents) { parent.children = GetChildrenByParentName();//assume this gets parents from db by parentName } Thank you

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  • Difference between macros and functions in C in relation to instruction memory and speed

    - by DAHANS
    To my understanding the difference between a macro and a function is, that a macro-call will be replaced by the instruction in the definition, and a function does the whole push, branch and pop -thing. Is this right, or have I understand something wrong? Additionally, if this is right, it would mean, that macros would take more space, but would be faster (because of the lack of the push,branch and pop instructions.), wouldn't it?

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  • Ruby on rails edit form for has_one relation

    - by user2900873
    I have a clan.rb and clan_options.rb clan.rb class Clan < ActiveRecord::Base has_one :options, :class_name => "ClanOptions", :foreign_key => "clan_id", dependent: :destroy end clan_options.rb class ClanOptions < ActiveRecord::Base belongs_to :clan end To create an edit form for clan.rb I use the following: <%= form_for @clan, :html => {:class => 'form-horizontal'} do |clan| %> <fieldset> <!-- form stuff --> </fieldset> <% end %> It works how I want. But now I want to create an edit form for the clan_options.rb, I have no idea how to do this. If anymore information is needed to solve this, ask me.

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  • One-to-One relation classes

    - by SeyZ
    I want to have a class named ProjectDirectory and a class named MetaDirectory. Each project has a MetaDirectory which contains some meta data. Is it the good way to write the classes like this: class ProjectDirectory(object): def __init__(self, directory=None): self.directory = directory self.meta_directory = MetaDirectory(self) def __repr__(self): return self.directory class MetaDirectory(object): def __init__(self, project_directory=None): self.project_directory = project_directory self.directory = "%s/.meta/" % project_directory ProjectDirectory has a reference to MetaDirectory and MetaDirectory has a reference to ProjectDirectory. Is there an other solution or this solution is good ?

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  • Select_related() backwards relation - auto model population

    - by Nick
    Hi. If I have the following model: class Contact(models.Model) name = models.CharField(max_length=100) ... class ContactAddress(models.Model) line1 = models.CharField(max_length=100) line2 = models.CharField(max_length=100) ... contact = models.ForeignKey(Contact) I now want to grab all Contacts and for the address to be auto populated. What would be the best way to do this? The only way I have found so far is to filter out the Contacts I want and loop around each contact and assign this to Contact.addresses. I then use this for outputting each Contacts address within a template. Is there a better way of doing this? Select_related() almost does what I want, but doesn't seem to be able to work in the opposite direction. Thanks in advance for your help on this one!

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  • using onDelete with Doctrine 2

    - by tamir
    I can't get the onDelete to work in Doctrine2 (with YAML Mapping). I tried this relation in my Product class: oneToOne: category: targetEntity: Category onDelete: CASCADE But that doesn't work.. EDIT: I've set the ON DELETE: CASCADE manually in the database imported the YAML mapping with doctrine:mapping:import, emptied the database updated it from the schema with doctrine:schema:update and got no ON DELETE in the foreign key.. so looks like even Doctrine doesn't know how to do it lol..

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  • Relation between " lines of the longest working program " in a language and familiarity with it?

    - by Tim
    In some computer master program online application, it says: Please list the programming languages in which you have written programs. For each language, indicate the length in lines of the longest working program you have written in that language. You may approximate, but only count those parts of the program that you wrote yourself. I don't quite remember that, and I have never counted the lines of each program. Do programmers always know approximately how many lines in each of his programs, and keep record of them? What is the relation between " lines of the longest working program " in a language and familiarity with it? Typically, how many lines will indicate the programmer being excellent, good, fair, or unfamiliar with the language? Is knowing "lines of the longest working program" really helpful?

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  • Rails Model Relationship: Has one but also belongs to many

    - by Lowgain
    I have two Models, Modela and Modelb. Modela can only own one Modelb, but Modelb can be a part of many Modela's. What I have right now is class Modela < ActiveRecord::Base has_one :modelb end class Modelb < ActiveRecord::Base belongs_to :modela, :foreign_key => "modela_id" #might not make sense? end Not too sure about the whole :foreign_key thing I was doing there, but it was where it was when I left off. As I am trying to allow Modelb to be part of many Modela's, I don't want to add a modela_id field to the Modelb table. What is the best way to do this?

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  • Finding recurrence relations of an algorithm

    - by Roarke
    I'm reading my algorithms text book, and I'm reading about recurrence relations and finding the algorithms big O complexity. I run across this line "In the case of the merge-sort algorithm, we get the recurrence equation: t(n) = b if n < 2 = 2t(n/2) +bn if n >= 2 for b > 0 my response was "how the heck did we know that?!?!" So i'm wondering if there is a systematic approach, or just a logical way of getting these recurrence relations from the algorithms can some one explain where the b and the two 2's come from?

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  • How to delete refClass record in Doctrine?

    - by terrani
    Hi all! I have many-to-many relations with the following tables. post tag post_tag I created three classes with Doctrine, so I have the following classes as well. BasePost BaseTag BasePostTag in the setUp() method, I defined relations. I like to delete tag record when I delete post record. So I simply put cascade as descirbed on Doctrine document. $this->hasMany("Tag as Tags",array( 'refClass' => 'PostTag', 'local'=>'object_id', 'foreign'=>'tag_id', 'cascade'=> array('delete') )); it works without a problem. My questions is, how do I delete a record from post_tag table? Do I need to create a query myself?

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  • Rails 3 query in multiple date ranges

    - by NeoRiddle
    Suppose we have some date ranges, for example: ranges = [ [(12.months.ago)..(8.months.ago)], [(7.months.ago)..(6.months.ago)], [(5.months.ago)..(4.months.ago)], [(3.months.ago)..(2.months.ago)], [(1.month.ago)..(15.days.ago)] ] and a Post model with :created_at attribute. I want to find posts where created_at value is in this range, so the goal is to create a query like: SELECT * FROM posts WHERE created_at BETWEEN '2011-04-06' AND '2011-08-06' OR BETWEEN '2011-09-06' AND '2011-10-06' OR BETWEEN '2011-11-06' AND '2011-12-06' OR BETWEEN '2012-01-06' AND '2012-02-06' OR BETWEEN '2012-02-06' AND '2012-03-23'; If you have only one range like this: range = (12.months.ago)..(8.months.ago) we can do this query: Post.where(:created_at => range) and query should be: SELECT * FROM posts WHERE created_at BETWEEN '2011-04-06' AND '2011-08-06'; Is there a way to make this query using a notation like this Post.where(:created_at => range)? And what is the correct way to build this query? Thank you

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  • Big-O complexity of c^n + n*(logn)^2 + (10*n)^c

    - by zebraman
    I need to derive the Big-O complexity of this expression: c^n + n*(log(n))^2 + (10*n)^c where c is a constant and n is a variable. I'm pretty sure I understand how to derive the Big-O complexity of each term individually, I just don't know how the Big-O complexity changes when the terms are combined like this. Ideas? Any help would be great, thanks.

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  • generate parent child relation from the array to print a multi-level menu?

    - by Karthick Selvam
    How to get parent child relation from this array to print a multi-level menu $menus = array ( 0 => array ( 'id'=>0, 'check' => 1, 'display' =>'Arete Home', 'ordering' => -10, 'parent' => none, ), 1 => array ( 'id'=>1, 'check' => 1, 'display' => 'Submit Paper', 'ordering' => -10, 'parent' => 2, 'subordering' => -10, ), 2 => array ( 'id'=>2, 'check' => 1, 'display' => 'Buy Now', 'ordering' => -10, 'parent' => 1, 'subordering' => -10, ), 1461 => array ( 'id'=>1461, 'check' => 1, 'display' => 'Where are We?', 'ordering' => -10, 'parent' => 2, 'subordering' => -10, ), 1463 => array ( 'id'=>1463, 'check' => 1, 'display' =>' About Me?', 'ordering' => -10, 'parent' => 2, 'subordering' => -10, ), 1464 => array ( 'id'=>1464, 'check' => 1, 'display' => 'About You?', 'ordering' => -10, 'parent' => 2, 'subordering' => -10, ), 1465 => array ( 'id'=>1465, 'check' => 1, 'display' => 'About who?', 'ordering' => -10, 'parent' => 1, 'subordering' => -10, ), ); code sample: foreach($menus as $id=>$values) { $values['parent']=isset($values['parent']) ? $values['parent'] : 0; $menus[$values['parent']]['childs'][$id]=$values; unset($menus[$id]); } foreach($menus as $id1=>$value2) { $value2['parent']=isset($value2['parent']) ? $value2['parent'] : 0; $menus[$value2['parent']]['childs'][$id1]=$value2; unset($menus[$id1]); }

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  • errors with libosmscout [migrated]

    - by Katlego Moukangwe
    I am using the libosmscout library for routing and I get the following error when I run the Routing demo; Routing . 169639811 169639816 169639831 253045594 //Running the routing demo with the map in the current directory. Cannot get start way! There was an error while calculating the route! I think It might be during the import stage since I get the following warnings; !! Cannot resolve way member 28693141 for relation 28322 boundary_administrative Mecklenburg-Vorpommern !! Cannot resolve way member 152675051 for relation 28936 boundary_administrative Bergedorf !! Cannot resolve way member 26496646 for relation 28964 boundary_administrative Harburg (Hamburg) !! Node 323985058 of way 135078286 cannot be joined with any other way of the relation 1817154 Neuenkirchen WW Multipolygon relation 2136137 has conflicting types for outer boundary (place_island vs. boundary_administrative) !! Cannot resolve way member 162656856 for relation 2174826 landuse_forest

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  • How is this relation in 4th normal form? Is the dependency trivial?

    - by squ
    I have a question that concerns multi value dependency. The relation looks like this: R(A,B) with A -->> B (A multi value determines B) I've been told that this relation is in 4th normal form, but I don't really se how. I know that if the multi value dependency is trivial, then it doesn't violate the 4th normal form. But is this trivial? It would be trivial if it, for example, looked like this: {A,B} -->> B But the first dependency example shouldn't be trivial. The other rule for 4th NF says that A in this case needs to be a super key of the relation, but it isn't. As far as I can tell, A isn't a super key, since {A,B} is needed to identify a tuple. So the question is, why is this in 4th normal form? It seems to be violating both of the rules.

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  • What&rsquo;s wrong with See[Mike]Code? (no relation)

    - by mbcrump
    I have been hearing a lot about the website See[Mike]Code. Basically, the site creates an interview url and a job candidate url and lets you see the potential programmer’s code (specifically .NET developer). Below is the candidate’s URL   Below is the interviewer url   So you might think, ah, this is a good thing. We can screen candidates cheaper and more efficiently. In reality, this is only a good thing if you want your programmer to develop using notepad.  I use the most efficient tools that exist to do my job. I would simply fire up VS2010 and type “for” and hit the tab key twice and get the following template.   I have no problem keeping MSDN/Google in one of my monitors. I spend time learning VS macros and using Aurora XAML/Expression to produce my XAML for WPF. Sure, I can write a for loop without using the VS Macro, but the real question is, “Why should I?”. My point being, if you really want to test a .NET programmer knowledge then fire up his native working environment and let him use the features of the IDE to develop the simple 10-line program. For a more sophisticated program, then give him 20 minutes and allow access to msdn/google. If the programmer cannot find at the right path then give him the boot.

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  • What does "enterprise" means in relation to software architecture?

    - by SkonJeet
    I see the term "enterprise" being thrown around software developers and programmers a lot and used loosely it seems. en·ter·prise/'ent?r?priz/ Noun: A project or undertaking, typically one that is difficult or requires effort. Initiative and resourcefulness. Can someone please clarify what this term actually encompasses? "At an enterprise level", "enterprise scale"? There are even "enterprise editions" of things. What exactly does it mean? It obviously doesn't make sense judging by the above definition so more specifically to software what does one mean when using the word enterprise? EDIT: To add a spin on this - how does this term then fit into phrases such as Enterprise Framework Model? What does data access and data context have to do with company-wide descriptions?

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  • When is the best time to do self learning in relation with software management?

    - by shankbond
    It all started from here. I have been following Software Estimation: Demystifying the Black Art (Best Practices (Microsoft)). The third chapter says that in Software Management: You cannot give too much time to software developers, if you give it to them, then it is likely that extra time given to them will be filled by some other tasks (in other words, the developers will eat that time :)) Parkinson's Law You can also not squeeze the time from their schedule because if you do that, it is likely that they will develop poor quality product, poor design and will hurt you in the long run, there will be a panic situation and total chaos in the project, lots of rework etc. My question is related to the first point. If you don't give enough time then will the typical software engineer learn his/her skills? The market is always coming with new technologies, you need to learn them. Even with the existing familiar technologies there are always best practices and dos and don'ts.

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  • What is the relation between NetworkManager and network service in Fedora/RHEL/Centos?

    - by Patrick L
    Hi I am new to Fedora/Centos/RHEL. I am confused about NetworkManager and network service in these Linux OS. May I know what is the relation between NetworkManager and network service? If I am using NetworkManager, do i need to turn off network service? Similarly, if I am using network service, do I need to turn off NetworkManager? Will they conflict with each other if I use both application at the same time?

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  • Do you know any studies on relation of productivity of a programmer and the workstation used?

    - by Tomasz Blachowicz
    I was wondering if there are any studies (formal or not-so-formal) that show correlation between a developer productivity and the workstation used to develop software. It is often heard as argument that the high spec workstations increase the productivity (or the low spec machines impact productivity to the greater extent). To me it sound reasonable, however I'd like to verify the statement with some studies if such exists. Can you help me with that?

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