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  • Django foreign key error

    - by Hulk
    In models the code is as, class header(models.Model): title = models.CharField(max_length = 255) created_by = models.CharField(max_length = 255) def __unicode__(self): return self.id() class criteria(models.Model): details = models.CharField(max_length = 255) headerid = models.ForeignKey(header) def __unicode__(self): return self.id() In views, p_l=header.objects.filter(id=rid) for rows in row_data: row_query =criteria(details=rows,headerid=p_l) row_query.save() In row_query =criteria(details=rows,headerid=p_l) there is an error saying 'long' object is not callable in models.py in __unicode__, What is wrong in the code Thanks..

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  • Mode specific key bindings

    - by rejeep
    Hey, I have a minor mode that also comes with a global mode. The mode have some key bindings and I want the user to have the posibility to specify what bindings should work for each mode. (my-minor-mode-bindings-for-mode 'some-mode '(key1 key2 ...)) (my-minor-mode-bindings-for-mode 'some-other-mode '(key3 key4 ...)) So I need some kind of mode/buffer-local key map. Buffer local is a bit problematic since the user can change the major mode. I have tried some solutions of which neither works any good. Bind all possible keys always and when the user types the key, check if the key should be active in that mode. Execute action if true, otherwise fall back. Like the previous case only that no keys are bound. Instead I use a pre command hook and check if the key pressed should do anything. For each buffer update (whatever that means), run a function that first clears the key map and then updates it with the bindings for that particular mode. I have tried these approaches and I found problems with all of them. Do you know of any good way to solve this? Thanks!

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  • Database Instance

    - by Sam
    I read a statement from an exercise: construct a database instance which conforms to diagram 1 but not to diagram 2. The diagrams are different n-ary relationships that have different relationships. Diagram 1 has a many to one to many to one relationship. Diagram 2 has many to many to many to one relationship. So, to really understand this problem, what does a database instance mean? Is it to make an example or abstract entities like a1, a2, or a3. Thanks for your time.

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  • Synonym for "Many-to-Many" relationship (relational databases)

    - by Byron
    What's a synonym for a "many-to-many" relationship? I've finished writing an object-relational mapper but I'm still stumped as to what to name the function that adds that relation. addParent() and addChild() seemed quite logical for the many-to-one/one-to-many and addSuperclass() for one-to-one inheritance, but addManyToMany() would sound quite unintuitive to an object-oriented programmer. addSibling() or addCousin() doesn't really make sense either. Any suggestions? And before you dismiss this as a non-programming question, please remember that consistent naming schemes and encapsulation are pretty integral to programming :)

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  • rails override default getter for a relationship (belongs_to)

    - by brad
    So I know how to override the default getters for attributes of an ActiveRecord object using def custom_getter return self[:custom_getter] || some_default_value end I'm trying to achieve the same thing however for a belongs to association. For instance. class Foo < AR belongs_to :bar def bar return self[:bar] || Bar.last end end class Bar < AR has_one :foo end When I say: f = Foo.last I'd like to have the method f.bar return the last Bar, rather than nil if that association doesn't exist yet. This doesn't work however. The reason is that self[:bar] is always undefined. It's actually self[:bar_id]. I can do something naive like: def bar if self[:bar_id] return Bar.find(self[:bar_id]) else return Bar.last end end However this will always make a db call, even if Bar has already been fetched, which is certainly not ideal. Does anyone have an insight as to how I might have a relationship such that the belongs_to attribute is only loaded once and has a default value if not set.

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  • Using a UIPickerView to make a CoreData Relationship

    - by DVG
    Okay, so I have a fairly simple application set up. I have two different CoreData Entities, Games and Platforms, each have one attribute: name, and they have a one-to-many relationship between them. Platforms are populated on the first launch of the application, and will never change as a result of user input. I'm working on my Add view to let the user add new games to their personal database, and each game should select from a platform. The add view itself is a grouped table view with static custom cells. Tapping the platform cell should advance the user to another view to select the platform. My thought is that UIPickerView seems like a logical choice for the control, since the Platform list is static, but I'm not sure how to use it with CoreData. Even if I construct a fetch request to get the Platform objects and extract the strings out, how do I go about linking the new Game object to the original Platform object?

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  • Ruby on Rails ActiveRecord: eager loading issue with foreign and primary key

    - by Krishnaswamy Subramanian
    The eager loading on Ruby on Rails is not working properly for the following scenario. First we had a model called marks which has the following fields id, student, subject, mark the student is a string column which has the active directory login value, later on for reporting functionality we introduce another table called user which has the following fields id, ad_name, full_name Now on the Mark model, we have added the belongs to class belongs_to :student_details, :class_name = "User", :foreign_key = "student", :primary_key = "ad_name" and when loading using the ActiveRecord's find method we are passing in the include conditon for eager loading Marks.find(:all, :include = :reserved_user) but when the find is executed, for each and every mark a student select query executed. Is this a known bug in ROR? or am i missing something?

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  • Sqlalchemy+elixir: How query with a ManyToMany relationship?

    - by Hugo
    Hi, I'm using sqlalchemy with Elixir and have some troubles trying to make a query.. I have 2 entities, Customer and CustomerList, with a many to many relationship. customer_lists_customers_table = Table('customer_lists_customers', metadata, Column('id', Integer, primary_key=True), Column('customer_list_id', Integer, ForeignKey("customer_lists.id")), Column('customer_id', Integer, ForeignKey("customers.id"))) class Customer(Entity): [...] customer_lists = ManyToMany('CustomerList', table=customer_lists_customers_table) class CustomerList(Entity): [...] customers = ManyToMany('Customer', table=customer_lists_customers_table) I'm tryng to find CustomerList with some customer: customer = [...] CustomerList.query.filter_by(customers.contains(customer)).all() But I get the error: NameError: global name 'customers' is not defined customers seems to be unrelated to the entity fields, there's an special query form to work with relationships (or ManyToMany relationships)? Thanks

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  • MySQL nested set hierarchy with foreign table

    - by Björn
    Hi! I'm using a nested set in a MySQL table to describe a hierarchy of categories, and an additional table describing products. Category table; id name left right Products table; id categoryId name How can I retrieve the full path, containing all parent categories, of a product? I.e.: RootCategory > SubCategory 1 > SubCategory 2 > ... > SubCategory n > Product Say for example that I want to list all products from SubCategory1 and it's sub categories, and with each given Product I want the full tree path to that product - is this possible? This is as far as I've got - but the structure is not quite right... select parent.`name` as name, parent.`id` as id, group_concat(parent.`name` separator '/') as path from categories as node, categories as parent, (select inode.`id` as id, inode.`name` as name from categories as inode, categories as iparent where inode.`lft` between iparent.`lft` and iparent.`rgt` and iparent.`id`=4 /* The category from which to list products */ order by inode.`lft`) as sub where node.`lft` between parent.`lft` and parent.`rgt` and node.`id`=sub.`id` group by sub.`id` order by node.`lft`

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  • Rails AR validates_uniqueness_of against polymorphic relationship

    - by aaronrussell
    Is it posible to validate the uniqueness of a child model's attribute scoped against a polymorphic relationship? For example I have a model called field that belongs to fieldable: class Field < ActiveRecord::Base belongs_to :fieldable, :polymorphic => :true validates_uniqueness_of :name, :scope => :fieldable_id end I have several other models (Pages, Items) which have many Fields. So what I want is to validate the uniqueness of the field name against the parent model, but the problem is that occasionally a Page and an Item share the same ID number, causing the validations to fail when they shouldn't. Am I just doing this wrong or is there a better way to do this?

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  • Applying the Hibernate filter attribute to a Bag with a many-to-many relationship

    - by David P
    Consider the following Hibernate mapping file: <hibernate-mapping ...> <class name="ContentPackage" table="contentPackages"> <id name="Id" column="id" type="int"><generator class="native" /></id> ... <bag name="Clips" table="contentAudVidLinks"> <key column="fk_contentPackageId"></key> <many-to-many class="Clip" column="fk_AudVidId"></many-to-many> <filter name="effectiveDate" condition=":asOfDate BETWEEN startDate and endDate" /> </bag> </class> </hibernate-mapping> When I run the following command: _session.EnableFilter("effectiveDate").SetParameter("asOfDate", DateTime.Today); IList<ContentPackage> items = _session.CreateCriteria(typeof(ContentPackage)) .Add(Restrictions.Eq("Id", id)) .List<ContentPackage>(); The resulting SQL has the WHERE clause on the intermediate mapping table (contentAudVidLinks), rather than the "Clips" table even though I have added the filter attribute to the Bag of Clips. What am I doing wrong?

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  • NHibernate ManyToMany Relationship Cascading AllDeleteOrphan StackOverflowException

    - by Chris
    I have two objects that have a ManyToMany relationship with one another through a mapping table. Though, when I try to save it, I get a stack overflow exception. The following is the code for the mappings: //EventMapping.cs HasManyToMany(x => x.Performers).Table("EventPerformer").Inverse().Cascade.AllDeleteOrphan().LazyLoad().ParentKeyColumn("EventId").ChildKeyColumn("PerformerId"); //PerformerMapping.cs HasManyToMany<Event>(x => x.Events).Table("EventPerformer").Inverse().Cascade.AllDeleteOrphan().LazyLoad().ParentKeyColumn("PerformerId").ChildKeyColumn("EventId"); When I change the performermapping.cs to Cascade.None() I get rid of the exception but then my Event Object doesn't have the performer I associate with it. //In a unit test, paraphrased event.Performers.Add(performer); //Event eventRepository.Save<Event>(event); eventResult = eventRepository.GetById<Event>(event.id); //Event eventResult.Performers[0]; //is null, should have performer in it How should I be writing this properly? Thanks

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  • Silverlight error-handling conventions: There is no relationship between onSilverlightError and Repo

    - by rasx
    When I see the call System.Windows.Browser.HtmlPage.Window.Eval (which is evil) in ReportErrorToDOM (in App.xaml.cs) this shows me that it has no relationship to onSilverlightError. So what kind of JavaScript-based scenario calls onSilverlightError? When will onSilverlightError definitely be needed? What are Silverlight error-handling conventions in general? This is a very important comment by Erik Monk but needs more detail: There are 2 kinds of terminal errors in Silverlight. 1) Managed errors (hit the managed Application_UnhandledException method). Note that some errors may not even get to this point. If the managed infrastructure can't be loaded for some reason (out of memory error maybe...), you won't get this kind of error. Still, if you can get it, you can use a web service (or the CLOG project) to communicate it back to the server. 2) Javascript errors.

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  • NHibernate - does it work well with database-level cascading deletions on foreign key constraints

    - by Nelson LaQuet
    Dose nHibernate play well with database level cascading deletions? What I mean is that if I have a constraint set at the RDBMS level to cascade delete all orphans, will nHibernate invoke any custom delete logic at the application level if I were to delete an entity though nHibernate? Or should I remove the cascading deletions from the RDBMS level and just use the cascading delete feature of nHibernate itself by defining that behavior though its configuration? Thanks

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  • SQL: many-to-many relationship, IN condition

    - by Maarten
    I have a table called transactions with a many-to-many relationship to items through the items_transactions table. I want to do something like this: SELECT "transactions".* FROM "transactions" INNER JOIN "items_transactions" ON "items_transactions".transaction_id = "transactions".id INNER JOIN "items" ON "items".id = "items_transactions".item_id WHERE (items.id IN (<list of items>)) But this gives me all transactions that have one or more of the items in the list associated with it and I only want it to give me the transactions that are associated with all of those items. Any help would be appreciated.

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  • has_many through a habtm relationship in Rails

    - by macek
    I'm trying to define a has_many X, :through => Y where Y is a habtm relationship. Rails is throwing a fit about this. See comment in user model: class User < ActiveRecord::Base has_many :posts # I want to display a list of all tags this user is involved in has_many :tags, :through => :posts # ERROR end class Post < ActiveRecord::Base has_and_belongs_to_many :tags end class Tag < ActiveRecord::Base has_and_belongs_to_many :posts end What can I do to fix this?

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  • validates_uniqueness_of with HABTM relationship

    - by jeffshantz
    I've got a HABTM relationship between two models: Publication and Author. I want to ensure that one cannot create a publication with the same title, year, and author list. However, if I try something like this: class Publication < ActiveRecord::Base validates_uniqueness_of :title, :scope => [:year, :authors] end This obviously won't work since there is no authors column. Can this be done with validates_uniqueness_of, or do I need a custom validator? Thank you.

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  • Cannot set g:checkbox to off for a child on one-to-many relationship

    - by icon911
    Got a weird issue with g:checkbox not being saved when its switched from on to off for a child in one-to-many relationship. For example: class Parent { Boolean enabled static hasMany = [children: Child] static constraints = { enabled(blank: true, nullable: true) } } class Child { Boolean enabled static belongsTo = [parent: Parent] static constraints = { enabled(blank: true, nullable: true) } } Posting to Parent controller true/false values will work for Parent: <g:checkBox name="enabled" value="${parentInstance?.enabled}"/> However, not for Child! When posting to Parent controller I can only go from false to true, trying to change from true to false again will not work: <g:each in="${parentInstance.children}" status="i" var="child"> <g:checkBox name="child[${i}].enabled" value="${child?.enabled}" /> </g:each> That seems to be a bug. Any ideas? Thanks.

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  • Core Data Relationships in pre-populated SQLite database

    - by Cardinal
    Hi All, I'm new to Core Data. Currently I have following tables on hand: tbl_teahcer tbl_student tbl_course tbl_student_course_map ----------- ----------- ---------- ---------------------- teacher_id student_id course_id student_id name name name course_id teahcer_id And I'm going to make the xcdatamodel as below: Course Teacher ------ ------- name name teacher <<----------> courses students <<---| | Student | ------- | name |----->> courses My questions are as follows: As I'd like to create TableView for Cource Entity, is it a must to create the Inverse Relationship from Teacher to Course, and Student to Course? What is the beneit for having the Inverse Relationship? I got some pre-defined data on hand, and I'd like to create a SQLite storage for pre-populated source. How can I set up the relationships (both directions) in SQLite? Thank you for your help! Regards, Cardinal

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  • How do I order by foreign attribute for belongs_to refernece where there are 2 keys to foreign table

    - by Will
    I have a Model which has a belongs_to association with another Model as follows class Article belongs_to :author, :class_name => "User" end If I wanted to find all articles for a particular genre ordered by author I would do something like the following articles = Article.all(:includes => [:author], :order => "users.name") However if Article happens to have two references to User how can I sort on :author? class Article belongs_to :editor, :class_name => "User" belongs_to :author, :class_name => "User" end I have tried articles = Article.all(:includes => [:author], :order => "users.name") #=> incorrect results articles = Article.all(:includes => [:author], :order => "authors.name") #=> Exception Thrown

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  • Using attr_accessible in a join model with has_many :through relationship

    - by Paulo Oliveira
    I have a USER that creates a COMPANY and become an EMPLOYEE in the process. The employees table has an :user_id and a :company_id. class User has_many :employees has_many :companies, :through => :employees class Employee belongs_to :user belongs_to :company attr_accessible :active class Company has_many :employees has_many :users, :through => employees Pretty basic. But here's the thing, the resource EMPLOYEE has other attributes than its foreign keys, like the boolean :active. I would like to use attr_accessible, but this causes some problems. The attribute :user_id is set right, but :company_id is nil. @user.companies << Company.new(...) Employee id:1 user_id:1 company_id:nil So my question is: if :user_id is set right, despite it is not an attr_accessible, why :company_id isn't set right just the same? It shouldn't be an attr_accessible. I'm using Rails 3.0.8, and have also tested with 3.0.7.

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  • Dajano admin site foreign key fields

    - by user292652
    hi i have the following models setup class Player(models.Model): #slug = models.slugField(max_length=200) Player_Name = models.CharField(max_length=100) Nick = models.CharField(max_length=100, blank=True) Jersy_Number = models.IntegerField() Team_id = models.ForeignKey('Team') Postion_Choices = ( ('M', 'Manager'), ('P', 'Player'), ) Poistion = models.CharField(max_length=1, blank=True, choices =Postion_Choices) Red_card = models.IntegerField( blank=True, null=True) Yellow_card = models.IntegerField(blank=True, null=True) Points = models.IntegerField(blank=True, null=True) #Pic = models.ImageField(upload_to=path/for/upload, height_field=height, width_field=width, max_length=100) class PlayerAdmin(admin.ModelAdmin): list_display = ('Player_Name',) search_fields = ['Player_Name',] admin.site.register(Player, PlayerAdmin) class Team(models.Model): """Model docstring""" #slug = models.slugField(max_length=200) Team_Name = models.CharField(max_length=100,) College = models.CharField(max_length=100,) Win = models.IntegerField(blank=True, null=True) Loss = models.IntegerField(blank=True, null=True) Draw = models.IntegerField(blank=True, null=True) #logo = models.ImageField(upload_to=path/for/upload, height_field=height, width_field=width, max_length=100) class Meta: pass #def __unicode__(self): # return Team_Name #def save(self, force_insert=False, force_update=False): # pass @models.permalink def get_absolute_url(self): return ('view_or_url_name') class TeamAdmin(admin.ModelAdmin): list_display = ('Team_Name',) search_fields = ['Team_Name',] admin.site.register(Team, TeamAdmin) my question is how do i get to the admin site to show Team_name in the add player form Team_ID field currently it is only showing up as Team object in the combo box

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  • Ruby on Rails - Primary and Foreign key

    - by Eef
    Hey, I am creating a site in Ruby on Rails, I have two models a User model and a Transaction model. These models both belong to an account so they both have a field called account_id I am trying to setup a association between them like so: class User < ActiveRecord::Base belongs_to :account has_many :transactions end class Transaction < ActiveRecord::Base belongs_to :account belongs_to :user end I am using these associations like so: user = User.find(1) transactions = user.transactions At the moment the application is trying to find the transactions with the user_id, here is the SQL it generates: Mysql::Error: Unknown column 'transactions.user_id' in 'where clause': SELECT * FROM `transactions` WHERE (`transactions`.user_id = 1) This is incorrect as I would like the find the transactions via the account_id, I have tried setting the associations like so: class User < ActiveRecord::Base belongs_to :account has_many :transactions, :primary_key => :account_id, :class_name => "Transaction" end class Transaction < ActiveRecord::Base belongs_to :account belongs_to :user, :foreign_key => :account_id, :class_name => "User" end This almost achieves what I am looking to do and generates the following SQL: Mysql::Error: Unknown column 'transactions.user_id' in 'where clause': SELECT * FROM `transactions` WHERE (`transactions`.user_id = 104) The number 104 is the correct account_id but it is still trying to query the transaction table for a user_id field. Could someone give me some advice on how I setup the associations to query the transaction table for the account_id instead of the user_id resulting in a SQL query like so: SELECT * FROM `transactions` WHERE (`transactions`.account_id = 104) Cheers Eef

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