foreign-key-relationship Questions
4
Solved
I thought that the common way to model a one-to-many relation in a database is via a foreign key relationship (i.e. one customer with many orders -> order table gets a FK reference to customer tabl...
Boleyn asked 12/7, 2011 at 15:12
2
Solved
So I've inherited some django.
The mySQL table is simple enough where parent is NOT a FK relationship just the "Parent" id:
CREATE TABLE `Child` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
...
Hepcat asked 22/7, 2011 at 10:15
3
Solved
Say I have two tables, a and b:
a {
pk as int
fk as int
...
}
b {
pk as int
...
}
I want to join a and b in a query like so:
FROM a
JOIN b on a.fk = b.pk
Which of the following scenario...
Mohenjodaro asked 27/6, 2011 at 13:57
3
Solved
This is pretty basic question I am sure but it's baffling me now :S
I have 2 tables, Students and Courses with a foreign key constraint, Many Students to 1 Course.
I store in my Students table a ...
Tybalt asked 24/5, 2011 at 16:20
1
Solved
I'm trying to use the foreign key association approach to achieve a one-to-one association in EF. In my case there's an association between a User and a Team, and I need a navigation property in ea...
Sievers asked 10/5, 2011 at 23:10
2
Solved
I have come to a conclusion that I should define both Independent Association and Foreign Key Association in My Code-First design. e.g:
public class Book
{
public int ID {get; set;}
public int ...
Hangout asked 19/4, 2011 at 12:59
1
Solved
Hi using SQL Server 2008,
I've built a small database for a baseball league, I'm having problem creating relationships between the Teams(PK: TeamID) and GameSchedule(PK: GameID, FK1: HomeTeamID, F...
Sailplane asked 14/4, 2011 at 11:57
2
Solved
I'm trying to understand the best way to define my POCO classes to be able to use Entity Framework code-first feature.
I want to define some foreign key relations in my classes, between the user an...
Deification asked 12/4, 2011 at 9:55
2
Solved
I have Flight, Person, and Glider models in a Rails 3 app. I've defined custom relationships because I need more than one foreign key referencing a Person from the flights table. Associations work ...
Mousy asked 5/4, 2011 at 15:44
1
Solved
I am trying to get instances of a class filtered by a field which is a foreign key but when I try to do that, I always get all the entries in the database, instead of the ones that match the criter...
Hardboiled asked 13/2, 2011 at 17:43
2
Solved
I have the following tables in a relational database:
[Sensor]
LocationId [PK / FK -> Location]
SensorNo [PK]
[AnalogSensor]
LocationId [PK/FK -> Sensor]
SensorNo [PK/FK -> Sensor]
Upper...
Undervalue asked 4/2, 2011 at 10:17
1
Solved
I have been successfully using NHibernate for quite some time now and
have been able to solve a lot of pitfalls with an application that I
developed with it and that is running in production. The...
Ascending asked 3/2, 2011 at 15:30
5
Solved
I want to setup table constraints for the following scenario and I’m not sure how to do it or if it’s even possible in SQL Server 2005.
I have three tables A,B,C. C is a child of B. B will have a ...
Visser asked 23/12, 2010 at 15:51
1
Solved
I'm trying to get some understanding of how Wordpress works and while inspecting the database I found that, in a multisite installation, there is a table called wp_site that seems always holding a ...
Curler asked 15/11, 2010 at 12:7
1
Solved
I have a django model like so:
class Profile_Tag(models.Model):
profile = models.ForeignKey(Profile)
tag = models.ForeignKey(Tag)
and a view like so:
pts = Profile_Tag.objects.all()
for pt in...
Sexology asked 1/11, 2010 at 23:49
2
Solved
Hopefully someone may be able to quickly advise the best way for me to model my ERD (I'm using IDEF1X & ERWin not Chen Notation) although it doesn't really matter.
Basically I have Three Enti...
Antofagasta asked 26/7, 2010 at 15:9
3
Solved
I want ActiveRecord to lookup by a non-id column from a table.
Hope this is clear when I give you my code sample.
class CoachClass < ActiveRecord::Base
belongs_to :coach
end
class Coach < ...
Fisken asked 23/7, 2010 at 11:20
6
Solved
I am working on a project where there are several types of users (students and teachers). Currently to store the user's information, two tables are used. The users table stores the information that...
Trig asked 3/7, 2010 at 18:21
2
Solved
I have the same problem as in the following post.
So I am wondering, why doesn't Rails support generating foreign keys by default?
Isn't it necessary?
Or are we supposed to do it manually?
Provost asked 7/4, 2010 at 1:46
2
Solved
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 ques...
Lashio asked 13/1, 2010 at 5:52
3
Solved
Is this a relationship that can be described in Ruby on Rails' ActiveRecord model relationships?
Customer Address
=================== =========
Billing_Address_Id >------}
}---|- AddressId
...
Abbotsun asked 14/11, 2009 at 16:38
3
Solved
SQL Server 2005.
I'm adding Foreign Key constraints to the database of an application that allegedly didn't need them. Naturally, the data has become unreliable and there are orphaned entries in t...
Frans asked 3/11, 2008 at 18:21
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