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  • Rails Associations Question

    - by Mutuelinvestor
    I'm new to rails and have volunteered to help out the local High School Track team with a simple database that tracks the runners performances. For the moment, I have three models: Runners, Race_Data and Races. I have the following associations. Runners have_many Race_Data Races have_many Race_Data I also want create the association Runners Have_Many Races Through Race_Data, but as my look at the diagram I have drawn, there is already a many to one relationship from Race_data to Races. Does the combination of Runners having many Race_Data and Race_Data having one Race imply a Many_to_Many relationship between Runners and Races?

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  • SugarCRM installation frozen

    - by Tom S.
    Hi there. I'm trying to install SugarCRM version 5.5.1. on a webhost. Everything goes nice until the step when the installation begins. The output is this one: Creating Sugar configuration file (config.php) Creating Sugar application tables, audit tables and relationship metadata ............. And never moves on! I check the database and can see that there are tables missing. The install.log file doesnt have any errors, and the last line in the file is: 2010-04-27 22:17:03...creating Relationship Meta for Bug It seems the installation stopped here, but i cant get why! Iv searched in the foruns, etc, but cant get it... Anyone had this issue? Any clues about whats happening? Thanks a lot

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  • ActiveRecord Associations Question

    - by Mutuelinvestor
    I'm new to rails and have volunteered to help out the local High School Track team with a simple database that tracks the runners performances. For the moment, I have three models: Runners, Race_Data and Races. I have the following associations. Runners have_many Race_Data Races have_many Race_Data I also want create the association Runners Have_Many Races Through Race_Data, but as my look at the diagram I have drawn, there is already a many to one relationship from Race_data to Races. Does the combination of Runners having many Race_Data and Race_Data having one Race imply a Many_to_Many relationship between Runners and Races?

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  • How to eager load sibling data using LINQ to SQL?

    - by Scott
    The goal is to issue the fewest queries to SQL Server using LINQ to SQL without using anonymous types. The return type for the method will need to be IList<Child1>. The relationships are as follows: Parent Child1 Child2 Grandchild1 Parent Child1 is a one-to-many relationship Child1 Grandchild1 is a one-to-n relationship (where n is zero to infinity) Parent Child2 is a one-to-n relationship (where n is zero to infinity) I am able to eager load the Parent, Child1 and Grandchild1 data resulting in one query to SQL Server. This query with load options eager loads all of the data, except the sibling data (Child2): DataLoadOptions loadOptions = new DataLoadOptions(); loadOptions.LoadWith<Child1>(o => o.GrandChild1List); loadOptions.LoadWith<Child1>(o => o.Parent); dataContext.LoadOptions = loadOptions; IQueryable<Child1> children = from child in dataContext.Child1 select child; I need to load the sibling data as well. One approach I have tried is splitting the query into two LINQ to SQL queries and merging the result sets together (not pretty), however upon accessing the sibling data it is lazy loaded anyway. Adding the sibling load option will issue a query to SQL Server for each Grandchild1 and Child2 record (which is exactly what I am trying to avoid): DataLoadOptions loadOptions = new DataLoadOptions(); loadOptions.LoadWith<Child1>(o => o.GrandChild1List); loadOptions.LoadWith<Child1>(o => o.Parent); loadOptions.LoadWith<Parent>(o => o.Child2List); dataContext.LoadOptions = loadOptions; IQueryable<Child1> children = from child in dataContext.Child1 select child; exec sp_executesql N'SELECT * FROM [dbo].[Child2] AS [t0] WHERE [t0].[ForeignKeyToParent] = @p0',N'@p0 int',@p0=1 exec sp_executesql N'SELECT * FROM [dbo].[Child2] AS [t0] WHERE [t0].[ForeignKeyToParent] = @p0',N'@p0 int',@p0=2 exec sp_executesql N'SELECT * FROM [dbo].[Child2] AS [t0] WHERE [t0].[ForeignKeyToParent] = @p0',N'@p0 int',@p0=3 exec sp_executesql N'SELECT * FROM [dbo].[Child2] AS [t0] WHERE [t0].[ForeignKeyToParent] = @p0',N'@p0 int',@p0=4 I've also written LINQ to SQL queries to join in all of the data in hopes that it would eager load the data, however when the LINQ to SQL EntitySet of Child2 or Grandchild1 are accessed it lazy loads the data. The reason for returning the IList<Child1> is to hydrate business objects. My thoughts are I am either: Approaching this problem the wrong way. Have the option of calling a stored procedure? My organization should not be using LINQ to SQL as an ORM? Any help is greatly appreciated. Thank you, -Scott

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  • How can this C and PHP programmer learn Ruby and Rails?

    - by Winston
    I came from a C, php and bash background, it was easy to learn because they all have the same C structure, which I can associate with what I already know. Then 2 years ago I learned Python and I learned it quite well, Python is easier for me to learn than Ruby. Then since last year, I was trying to learn Ruby, then Rails, and I admit, until now I still couldn't get it, the irony is that those are branded as easy to learn, but for a seasoned programmer like me, I just couldn't associate it with what I learned before, I have 2 books on both Ruby and Rails, and when I'm reading it nothing is absorbed into my mind, and I'm close to giving up... In ruby, I'm having a hard time grasping the concepts of blocks, and why there's @variables that can be accessed by other functions, and what does $variable and :variable do? And in Rails, why there's function like this_is_another_function_that_do_this, so thus ruby, is it just a naming convention or it's auto-generated with thisvariable _can_do_this_function. I'm still puzzled that where all those magic concepts and things came from? And now, 1 year of trying and absorbing, but still no progress... Edit: To summarize: How can I learn about blocks, and how can it be related to concepts from PHP/C? Variables, what does does it mean when a variable is prefixed with: @ $ : "Magic concepts", suchs as rails declarations of Records, what happens behind the scenes when I write has_one X OK so, bear with me with my confusion, at least I'm honest with myself, and it's over a year now since I first trying to learn ruby, and I'm not getting younger.. so I learned this in Bash/C/PHP solve_problem($problem) { if [ -e $problem == "trivial" ]; then write_solution(); else breakdown_problem_into_N_subproblems(\; define_relationship_between_subproblems; for i in $( command $each_subproblem ); do solve_problem $i done fi } write_solution(problem) { some_solution=$(command <parameters> "input" | command); command | command $some_solution > output_solved_problem_to_file } breakdown_problem_into_N_subproblems($problems) { for i in $problems; do command $i | command > i_can_output_a_file_right_away done } define_relationship_between_subproblems($problems) { if [ -e $problem == "relationship" ]; then relationship=$(command; command | command; command;) elsif [ -e $problem == "another_relationship" ]; relationship=$(command; command | command; command;) fi } In C/PHP is something like this solve_problem(problem) { if (problem == trivial) write_solution; else { breakdown_problem_into_N_subproblems; define_relationship_between_subproblems; for (each_subproblem) solve_problems(subproblem); } } And now, I just couldn't connect the dots with Ruby, |b|{ blocks }, using @variables, :variables, and variables_with_this_things..

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  • sql server 2000 and for xml explicit

    - by Marcin
    Hi everyone, I've got a problem with using for xml explicit in SQL Server 2000 (so I can't use the new path() stuff from sql 2005/8) Essentially I have two tables and the XML structure I want to have is <xml> <table_1 field1="foo" field2="foobar2" field3="foobar3"> <a_row_from_table_2 field1="goo" field2="goobar2" field3="goobar3" /> <a_row_from_table_2 field1="hoo" field2="hoobar2" field3="hoobar3" /> </table_1> </xml> That is, table_1 has a one-to-many relationship with table_2, and I want to make a hierarchy of it. So far I can't seem to get it, the closest I've managed to get is all the records from table1, with all the records from table2 appended to the very last element of table1 Any help with setting up this kind of relationship would be greatly appreciated. -Marcin

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  • Entity Framework and the XmlIgnoreAttribute

    - by Mikey Cee
    Say you have a one to one relationship in your entity model. The code generator will decorate it with the following attributes: [global::System.Xml.Serialization.XmlIgnoreAttribute()] [global::System.Xml.Serialization.SoapIgnoreAttribute()] public RelatedObject Relationship { get {...} set {...} } I want to serialize my parent object together with all its properties for which data has been loaded through an XML web service. Obviously, these related properties do not get serialized because of these attributes. So for my purposes I just want to remove these "don't serialize me" attributes. I can do a find and replace in the designer code, but any modifications I make in the designer will put these attributes back in. How do I permanently get rid of these attributes? VS 2008 / EF 3.5.

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  • Hibernate @OneToOne @NotNull

    - by Marty Pitt
    Is it valid to declare @OneToOne and @NotNull on both sides of a relationship, such as: class ChangeEntry { @OneToOne(cascade=CascadeType.ALL) @NotNull ChangeEntryDetails changeEntryDetails; } class ChangeEntryDetails { @OneToOne(cascase=CascadeType.ALL) @NotNull ChangeEntry changeEntry; } I can't find anything that says this is invalid, but it seems that during persistence at least one side of the relationship must be violated. (Eg., if writing changeEntry first, changeEntryDetails will be null temporarily). When trying this, I see an exception thrown not-null property references a null or transient value. I'd like to avoid relaxing the constraint if possible, because both sides must be present.

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  • ManyToMany Relation does not create the primary key

    - by Javi
    Hello, I have a ManyToMany relationship between two classes: ClassA and ClassB, but when the table for this relationship (table called objectA_objectB) there is no primary key on it. In my ClassA I have the following: @ManyToMany(fetch=FetchType.LAZY) @OrderBy(value="name") @JoinTable(name="objectA_objectB", joinColumns= @JoinColumn(name="idObjectA", referencedColumnName="id"), inverseJoinColumns= @JoinColumn(name="idObjectB", referencedColumnName="id") ) private List<ClassB> objectsB; and in my ClassB I have the reversed relation @ManyToMany List<ClassA> objectsA; I just want to make a primary key of both id's but I need to change the name of the columns as I do. Why is the PK missing? How can I define it? I use JPA 2.0 Hibernate implementation, if this helps. Thanks.

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  • creating managed objects using code in xcode & core-data

    - by themadpeacock
    New to objective-c xcode and core-data so sorry for the remedial question. I have set up a very simple data model: Entity1 and Entity2, both contain a single attribute (String) and a one-to-many relationship with the other. I want to scan Entity1 and depending on the results of the scan create one or more Entity2 objects that link to Entity1. How can I do this? I don’t understand how I create Entity2 type objects in code and how I would define the relationship to the Entity1 object they are related to. I come from a SQL programming background where inserting elements into the Entity2 table with the ID of the related Entiry1 entry is easy. I can’t get my head around the xcode core-data abstraction and would appreciate any help.

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  • Trying to verify understanding of foreign keys SQL Server

    - by msarchet
    So I'm working on just a learning project to expose myself to doing some things I do not get to do at work. I'm just making a simple bug and case tracking app (I know there are a million this is just to work with some tools I don't get to). So I was designing my database and realized I've never actually used Foreign Keys before in any of my projects, I've used them before but never actually setting up a column as a FK. So I've designed my database as follows, which I think is close to correct (at least for the initial layout). However When I try to add the FK's to the linking Tables I get an error saying, "The tables present in the relationship must have the same number of columns". I'm doing this by in SQLSMS by going to the Keys 'folder' and adding a FK. Is there something that I am doing wrong here, I don't understand why the tables would have to have the same number of columns for me to add a FK relationship between the tables?

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  • Binding Many-to-Many Core Data relationships in UI

    - by Kevin
    Basically my setup is this. I have a many-to-many relationship in Core Data where a student entity can have multiple courses, and a course entity can have multiple students. My problem is in trying to figure out how to bind this relationship to the UI in Interface Builder. I want to be able to add courses to a course array controller, then have those courses displayed in a popup menu in a NSTableView in the Edit Student window where you can add courses to a student. This is what I have so far: http://vimeo.com/10671726 It's probably easier to understand from the video. Thanks

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  • insertNewObjectForEntityForName: inManagedObjectContext: returning NSNumber bug?

    - by beinstein
    I'm relatively well versed in CoreData and have been using it for several years with little or no difficulty. All of a sudden I'm now dumbfounded by an error. For the life of me, I can't figure out why insertNewObjectForEntityForName:inManagedObjectContext: is all of a sudden returning some sort of strange instance of NSNumber. GDB says the returned object is of the correct custom subclass of NSManagedObject, but when I go to print a description of the NSManagedObject itself, I get the following error: *** -[NSCFNumber objectID]: unrecognized selector sent to instance 0x3f26f50 What's even stranger, is that I'm able to set some relationships and attributes using setValue:forKey: and all is good. But when I try to set once specific relationship, I get this error: *** -[NSCFNumber entity]: unrecognized selector sent to instance 0x3f26f50 Has anyone ever encountered anything like this before? I've tried clean all targets, restarting everything, even changing the model to the relationship in question is a to-one instead of a to-many. Nothing makes any difference.

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  • error 2016: Condition cannot be specified for Column member

    - by IP
    I am having some issues with Entity Framework in VS2010 The problem I'm getting is described very well here... http://social.msdn.microsoft.com/Forums/en/adonetefx/thread/cacf6a76-09a8-4c90-9502-d8b87c2f6bea It's basically happening when a Foreign key is pointed at the primary key of another table...but if I take off the StoreGeneratedPattern as "Identity", then it tries to insert a value into the identity field ** EDIT So, what it seems to be is that EF4 can't handle a null relationship when the primary key is set to StoreGeneratedPattern="Identity". If I create a FK pointing to this primary key, and make it nullable (effectively creating a 0...M relationship), then it throws this compilation error. Removing StoreGeneratedPattern="Identity" fixes the issue, but causes issues elseware It works if the foreign key is set to not nullable

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  • how to get group total in self refrenced data in data table ?

    - by Nikhil Vaghela
    I have three columns in my data table. 1) ProductID 2) ProductParentID 3) ProductTotal ProductID and ProductParentID are self refrencing columns where i can set parent child relationship and get child rows based on my relationship. Let us say i have following data Product1     Product11     Product12     Product13         Product131         Product132         Product133 Product2     Product21     Product22     Product23 Next to above hierarchy in Product total column what i want is total of each child rows and sum of those child rows product total should be rolled up to it parent product. E.g if Product 131 total is 10,Product 13 total is 15 and Product 133 total is 5 then the product 13 total should be 30. The logic should work for n number of self hierarchy. Is there any functionality in data table itself where i can achieve this without iterating through each row and do it manually ? Thanks.

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  • mySQL one-to-many query

    - by Stomped
    I've got 3 tables that are something like this (simplified here ofc): users user_id user_name info info_id user_id rate contacts contact_id user_id contact_data users has a one-to-one relationship with info, although info doesn't always have a related entry. users has a one-to-many relationship with contacts, although contacts doesn't always have related entries. I know I can grab the proper 'users' + 'info' with a left join, is there a way to get all the data I want at once? For example, one returned record might be: user_id: 5 user_name: tom info_id: 1 rate: 25.00 contact_id: 7 contact_data: 555-1212 contact_id: 8 contact_data: 555-1315 contact_id: 9 contact_data: 555-5511 Is this possible with a single query? Or must I use multiple?

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  • How to perform a many-to-many Linq query with Include in the EF.

    - by despart
    Hi, I don't know how to perform this query using Linq and the EF. Imagine I have three tables A, B and C. A and B have a many-to-many relationship. B and C have a 1-to-many relationship. I want to obtain records from B including C but filtering from A's Id. I can get easily the records from B: var b = Context.A.Where(x => x.Id.Equals(aId)).SelectMany(x => x.B); but when I try to include C I don't know how to do it: //This doesn't work var b = Context.A.Where(x => x.Id.Equals(aId)).SelectMany(x => x.B.Include("C")); Also I've tried this with no luck (it is equivalent to the above): //Not working var b = (from a in Context.A.Where(x => x.Id.Equals(aId)) from b in a.B.Include("C") select b); Thanks for your help.

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  • How do I delete a child entity from a parent collection with Entity Framework 4?

    - by simonjreid
    I'm using Entity Framework 4 and have a one-to-many relationship between a parent and child entity. I'm trying to delete a child using the parent repository by removing it from the parent's children collection: public virtual void RemoveChild(Child child) { children.Remove(child); } When I try to save the changes I get the following error: A relationship from the 'ParentChild' AssociationSet is in the 'Deleted' state. Given multiplicity constraints, a corresponding 'Child' must also in the 'Deleted' state. Surely I don't have to delete the child entity explicitly using a child repository!

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  • Best application for process flow with expandable attributes

    - by Marcus
    I am looking for the best software application to do the following I have a set of use cases that are in relationship to each other. I want to show an overview of this relationship. If the user desires the attributes for each use case (such as business rules, data elements, etc) should be expandable. This is potentially a large map which is the reason why the attributes should be expandable / collapsable. Finally all this needs to be printable. Any idea of the ideal application to do this? Thanks a lot in advance

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  • How to define one-to-many connection between a same model through another model

    - by Mekajiki
    I want to define one-to-many relationship as follows; User has one introducer User has many newcomers(who is introduced by the user) Use "Introduction" model instead of adding a column to users table. My table and model definition is as follows; DB Scheme: create_table "introductions", force: true do |t| t.integer "introducer_id" t.integer "newcomer_id" t.datetime "created_at" t.datetime "updated_at" User model: class User < ActiveRecord::Base has_many :introductions, foreign_key: :introducer_id has_many :newcomers, through: :introductions, source: :newcomer belongs_to :introduction, foreign_key: :newcomer_id belongs_to :introducer end Introduction model: class Introduction < ActiveRecord::Base belongs_to :introducer, class_name: 'User' belongs_to :newcomer, class_name: 'User' end This works fine: user1.newcomers.push user2 but, user2.introducer # => nil How can I define belongs_to relationship correctly?

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  • How to deal with many to many relationships with NSFetchedResultsController?

    - by Phil Yates
    OK so I have two entities in my data model (let's say entityA and entityB), both of these entities have a to-many relationship to each other. I have setup a NSFetchedResultsController to fetch a bunch of entityA. Now I'm trying to have the section names for the tableview be the title of entityB. sectionNameKeyPath:@"entityB.title" Now this causes a problem, where by the section name returned from that relationship appears to be ({title1}) or ({title1,title2...titleN}) obviously depending on how many different entityB's are involved. This doesn't look great in a tableview and doesn't group the objects as I would like. What I would like is a section per entityB title with entityA appearing under each section, under multiple sections if necessary. I'm at a loss as how I am supposed to achieve this whether I need to update the predicate to get the entity to appear multiple times or whether I need to update the section and header functions to do some processing as the controller loops through the objects. Any help is appreciated :) Thanks

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  • insertNewObjectForEntityForName:inManagedObjectContext: returning NSNumber bug?

    - by beinstein
    I'm relatively well versed in CoreData and have been using it for several years with little or no difficulty. For the life of me, I can't figure out why insertNewObjectForEntityForName:inManagedObjectContext: is all of a sudden returning some sort of strange instance of NSNumber. GDB says the returned object is of the correct custom subclass of NSManagedObject, but when I go to print a description of the NSManagedObject itself, I get the following error: *** -[NSCFNumber objectID]: unrecognized selector sent to instance 0x3f26f50 What's even stranger, is that I'm able to set some relationships and attributes using setValue:forKey: and all is good. But when I try to set one specific relationship, I get this error: *** -[NSCFNumber entity]: unrecognized selector sent to instance 0x3f26f50 I've tried everything from clean all targets, to restarting both mac and iPhone, even editing the model so that the relationship in question is to-one instead of to-many. No matter what I do, the same problem appears. Has anyone ever seen anything like this before?

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  • SQL efficiency argument, add a column or solvable by query?

    - by theTurk
    I am a recent college graduate and a new hire for software development. Things have been a little slow lately so I was given a db task. My db skills are limited to pet projects with Rails and Django. So, I was a little surprised with my latest task. I have been asked by my manager to subclass Person with a 'Parent' table and add a reference to their custodian in the Person table. This is to facilitate going from Parent to Form when the custodian, not the Parent, is the FormContact. Here is a simplified, mock structure of a sql-db I am working with. I would have drawn the relationship tables if I had access to Visio. We have a table 'Person' and we have a table 'Form'. There is a table, 'FormContact', that relates a Person to a Form, not all Persons are related to a Form. There is a relationship table for Person to Person relationships (Employer, Parent, etc.) I've asked, "Why this couldn't be handled by a query?" Response, Inefficient. (Really!?!) So, I ask, "Why not have a reference to the Form? That would be more efficient since you wouldn't be querying the FormContacts table with the reference from child/custodian." Response, this would essentially make the Parent is a FormContact. (Fair enough.) I went ahead an wrote a query to get from non-FormContact Parent to Form, and tested on the production server. The response time was instantaneous. *SOME_VALUE* is the Parent's fk ID. SELECT FormID FROM FormContact WHERE FormContact.ContactID IN (SELECT SourceContactID FROM ContactRelationship WHERE (ContactRelationship.RelatedContactID = *SOME_VALUE*) AND (ContactRelationship.Relationship = 'Parent')); If I am right, "This is an unnecessary change." What should I do, defend my position or should I concede to the managers request? If I am wrong. What is my error? Is there a better solution than the manager's?

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