Hi! Please regard the following Django models: ParentModel(models.Model): ... ChildModel(models.Model): parent = models.ForeignKey(ParentModel, related_name='children') Let's assume there is certain subset of all children in the database available as a queryset (call it the 1st set). Now, I'd like to gain access to the sub...
hi expert as per our last discussion regarding duplicate invoice no. and you have suggetsed code like: create table Invoice ( companyID int, invno varchar(50), primary key (companyID,Invno) ) worked fine. but another table is invcarat same has field like: companyID(int) invno(varchar) -------------------------...
My SQL database (Firebird) has a table named tTransaction. It contains two columns, senderFK and receiverFK. There are three other tables, tBufferStock, tFacility and tOutsideLocation. A sender or a receiver can be either a buffer stock, our own facility or a location outside. My problem is that I don't know how to let senderFK or rece...
i have entity A that has foreign key to entity B, does entity B need to have foreign key back to entity A? if yes, how? coz entity B, id already used for primary key entity A --> id, entity_a_name, foreign_key_entity_B entity B ---> id, entity_b_name ...
I have an entity A that has a foreign key of entity B: entity A --> id, entity_a_name, foreign_key_entity_B When I call return session.createCriteria(EntityA.class).list(); I get the property of entityB inside entity A as well. How do I make it lazy load so it will not load enityB if not needed? ...
entity A --> id, entity_a_name, foreign_key_entity_B entity B ---> id, entity_b_name when i delete entity B record, it suppose to auto delete entity A that has foreign_key_entity_B ? Error: ORA-02292: integrity constraint (schema.FKA630D2FB5F0F1180) violated - child record found ...
@Entity @Table(name = "BOOKTEST") @NamedQueries({@NamedQuery(name = "Booktest.findAll", query = "SELECT b FROM Booktest b"), @NamedQuery(name = "Booktest.findById", query = "SELECT b FROM Booktest b WHERE b.id = :id"), @NamedQuery(name = "Booktest.findByBookName", query = "SELECT b FROM Booktest b WHERE b.bookName = :bookName")}) public ...
Hello, I have a database application in which a group is modeled like this: TABLE Group ( group_id integer primary key, group_owner_id integer ) TABLE GroupItem ( item_id integer primary key, group_id integer, group_owner_id integer, Foreign Key (group_id, group_owner_id) references Group(group_id, group_owner_id) ) We ha...
I have 2 database tables: Teams and Games. For the purpose of this question, we are dealing with football (soccer) teams and games. Each Game has exactly 2 teams, generally a home team and an away team although occasionally both teams can be neutral. My question is whether I should represent this data relationship using 2 foreign keys...
Hi all. When I have an entity that holds a reference to a singular entity I can create an EntityKey and assign that value to the EntityNameReference.Value property. It works perfectly and like a charm. If I have an entity that holds a reference to multiple entities I cannot succeed in doing the same thing. Suppose an entity called Appli...
I am working on an application where I need to find the count of submitted items by users that have been referred by a user. For Example - User1 has referred 3 people (User2, User3, User4) and each of those users has submitted 5 articles. I am trying to find a way to get the count of submitted items in User1's tree (should be 15 in th...
I have table A and Table B. Table B contains two columns, Name and ID. Table A contains several columns and a foreign key column pointing to B.ID called B_ID On the client side, I have all the data I want to insert into Table A, except for B_ID. I have B.Name though. using link to sql I need to retrieve the id in table B based on the v...
I am using the ADO entity framework for the first time and am not sure of the best way of inserting db recored that contain foreign keys. this is the code that i am using, I would appreciate any comments and suggestion on this. using (KnowledgeShareEntities entities = new KnowledgeShareEntities()) { Question...
I'm trying to use foreign keys properly to maintain data integrity. I'm not really a database guy so I'm wondering if there is some general design principle I don't know about. Here's an example of what I'm trying to do: Say you want to build a database of vehicles with Type (car, truck, etc.), Make, and Model. A user has to input at le...
Is this a relationship that can be described in Ruby on Rails' ActiveRecord model relationships? Customer Address =================== ========= Billing_Address_Id >------} }---|- AddressId Shipping_Address_Id >------} So that I could have data that looks...
I'd like to have a parent-child hierarchy AND I'd like to have the concept of a "series-id" on the parent. So the parent (if you updated it) would expire the old unique key.. keep the series id and insert a second row. I'd like the children to "hang" off that series id rather than the unique id. Do you know if it's possible for Belong...
I have a model class ServiceRequest < ActiveRecord::Base has_many :services accepts_nested_attributes_for :services ... end and the child class Service < ActiveRecord::Base belongs_to :service_category, :foreign_key => "wsi_web_serv_cats_uid_fk" belongs_to :service_type, :foreign_key => "wsi_web_serv_types_uid_fk" belon...
I am creating BOOK_Issue table which will contain id of person to whom the book is issued. i have a column name user_id witch will contain ids from tbl_student as well as tbl_faculty. so how to set user_id field of book_issue table with reference to two primary key columns. ...
I wonder how JPA defines to handle following scenario: Table A: | Table B: ID FK_B | ID 1 10 | 10 2 null | 12 3 11 | I want all Table A entries with FK_B NULL or referencing not available Table B entry. public class A implements Serializable { @Id private Long id; @JoinColumn(name = "FK_B", nullable = true) ...
Hi, I wonder if there is a quicker way for this: *"I have my Management Studio open and I have a Db table with manes of columns listed in front of me. I know FK_SomeTable field is a ForeignKey. But I do not know it is an FK on what table. And I need to learn that."* So, normally I open the "Relationships" of that table, go one by one...