Hello, I am trying to design a database but I need some help with the relationships. Am i getting the table design right? Here is the database idea.. User will submit a howto, each howto will have one or more steps associated with(a one to many). each step can have random pictures associated with(another one to many). so I am thinking ...
Is there a way to get the foreign key type of the model my key relates to? Currently, I'm trying something like: def __init__(self, *args, **kwargs): super(JobOrderSupplementForm, self).__init__(*args, **kwargs) for field in self.fields: if type(self.fields[field]) == TypedChoiceField: fieldOp...
I am creating a self-related table: Table Item columns: ItemId int - PK; Amount money - not null; Price money - a computed column using a UDF that retrieves value according to the items ancestors' Amount. ParentItemId int - nullable, reference to another ItemId in this table. I need to avoid a loop, meaning, a sibling cannot become a...
My app has clients that each have a single billing profile. I'm envisioning my app having a "Client" model with an attribute called "billing_profile" which would reference another model called "BillingProfile". Rather than define "BillingProfile" with a foreign key back to "Client" (ie, "client = models.ForeignKey(Client)"), I was think...
This is a SQL design question. First, the setup. I have three tables: A, which is automatically populated based on a query against a linked server. The data in this table cannot be changed; B, which has just a dozen or so rows, containing the names for collections of A's; AtoB, which is the mapping table by which A's are organized into...
I'm teaching myself Rails, and as a test project I'm mocking up a simple question/answer app similar to stackoverflow. In my simplified version I have: questions answers users (the authors of questions and answers) I get that answers belong to questions. What's the proper relationship between users and questions? What's the proper re...
I've been toying with MySQL today and reading their documentation, gotten some handy information of optimization and a lot of things I didn't know. Now I've been adding foreign keys to my web application because it add constrains and I see it quite helpful. My doubt is, right now there is a Roles table and a Users table, I set a relati...
Possible Duplicate: Surrogate Vs. Natural/Business Keys The title says it all. If given two tables, Level1 [ID, Title, Number] Level2 [ID, FKID???, Title, Number] A user of the system understands that Level2 is related to Level1 with based on Level1's Number, my question to you is, would you make the relationship based on the...
I am getting an error when trying to create a relationship within two tables in Sql Server 2005. I am attempting to create the relationships using the database diagram feature. I have a Player table and a Message table. I want to create two relationships from the Message table to the Player table. I can successfully create the first rela...
Hi all! My doubt is about how to treat the follow thing: I have a system where a user belong to a company, and this user have their clients. How is the right way to get a list of all company clients and the follow user name?? In the client table where i have a field with the one of this relations: A company_id and user_id field Ju...
I have a database design case which I am curios whether Doctrine ORM supports it out-of-box. Product: columns: id: {type: integer, primary: true, autoincrement: true } type_id: { type: integer, notnull: true } brand_id: { type: integer, notnull: true } relations: ProductType: class: ProductType loc...
I have 3 tables Subcontract, Company, and a link table CompanyToSubcontract. The link table contains the Subcontract_id and the Company_id. The foreign keys were set-up in SQL and when I drug them into my dbml the one-to-many relationship arrows showed up and everything looked fine. However, when coding, it's as if the relationship is...
Hi all, I need help in auto populating the primary key values in foreign key table while inserting data in foreign key table. For Example: I have created table: create table Patient ( PatientId int IDENTITY(1,1) primary key, FirstName varchar(50), SurName varchar(50), Gender char(20), ) Say 5 rows are there in this Patient Table: Say...
In the application I am building, users can specify relationships between tables. Since I only determine this at runtime, I can't specify has_many or belongs_to relationships in the schema modules for startup. So given two tables; system and place, I would like to add the relationship to join records between them. I have part of the ...
I have a CRUD repository as fallowing: public class CrudRepository<T> : ICrudRepository<T> where T : class, IUnique { static DataContext db = new DataContext(); protected DataContext DataContext { get { return db; } } public virtual IQueryable<T> GetAll() { return db.GetTable<T>(...
Hi ! I am trying to make a messages functionality similar to the facebook. Just the message thing and not facebook. A brief descriptions does like this. 1) There are a number of users ( user table) 2) One person can send a message to one or more than one person. 3) There can be multiple reply to the same message. 4) If its send to multi...
Hello all, i am new to this topic. i want something like this. i have two tables in my sqliteDatabase one is master and another is child. Now if i delete a record from master suppose i delete a row from master where id=5, then all the records from the child table whose id = 5 deleted automatically. I don't know how to create triggers a...
In .net objects like DataTable when you have two grids(Master and Detail) and add a row to the second one(Detail), The new row will have the Foreign-Key Values automatically. How can i do it(I don't use DataTables because they suck)? thanks. ...
I'm finding django foreign keys a bit confusing, is there any way to do the view below, using a single query? # Model class Programme(models.Model): name = models.CharField(max_length = 64) class Actor(models.Model): programme = models.ForeignKey(Programme) name = models.CharField(max_length = 64) # View def list_actors(...
Title pretty much sums it up. Is there a technical name given to a table that stores primary key from two separate tables to create a linkage. i.e. car ( id, manufacturer, model, year, vin), passenger ( id, name ), linkage_table ( car, passenger ) Where car stores value of the id column from the car table and passenger stores the val...