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I have the Order table which contains information about a specific order, (when does it start, how many people, etc...) and that Order table has To-Many relationship to Menu Item table. I call that relationship "orderItems".
The compiler gives me warning...
Started by Hoang Pham on
, 3 posts
by 3 people.
Answer Snippets (Read the full thread at stackoverflow):
Just open....
You define a one-to-one relationship - one car to one driver an inverse is simple.
Lets say you have two tables - Cars and Drivers .
I ran into this warning and problem too! Here's what you need to know...
relationships).
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Today somebody told me that interface implementation in C# is just "Can-Do" relationship, not "Is-A" relationship. This conflicts with my long-time believing in LSP(Liskov Substitution Principle). I always think that all inheritance should means "Is-A...
Started by Morgan Cheng on
, 7 posts
by 7 people.
Answer Snippets (Read the full thread at stackoverflow):
I wouldn't get too hung up about framework use interfaces to designate... .
For example, as you can define parameters as interfaces, types that implement, and sometimes they can represent more of a normal "is-a" relationship.
An Is-A relationship.
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I the School class I have this code:
from student in this.Students where student.Teacher.Id == id select student
The Student class there are two relationships: Teacher and School. In the School class I'm trying to find out all the students whose Teacher...
Started by J. Pablo Fernández on
, 4 posts
by 4 people.
Answer Snippets (Read the full thread at stackoverflow):
}
I guess that this.Students is....
For example:
using (YourDataContext db = new YourDataContext()) { var query = from s in db.Students.Include("Teacher") where s.Teacher.ID == 1 select s; //etc.. .
The Include clause can be used in linq to entities query .
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Ask your Facebook Friends
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I am using the database diagram to simply drag one column in a table to another to associate them and then trying to save it. i have done this a million times in the past with no problems. Both of the data types are the same, uniqueidentifier.
Here is...
Started by Max Fraser on
, 3 posts
by 3 people.
Answer Snippets (Read the full thread at stackoverflow):
Run this query inside SQL Server Management Studio separately:
....
Are there customer orders with customer id's that don't exist in the customer table?
It means that there's a CustomerID in the CustomerOrder which can not be found in the Customer table .
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I have a 3rd party database where the primary key is a char datatype. When I run my query, I use an include to include the child table. The count is zero though. I look at sql profiler and results are returned. The only thing I can see is an issue with...
Started by Marsharks on
, 3 posts
by 3 people.
Answer Snippets (Read the full thread at stackoverflow):
If I use in my query to select from the child and include the parent, get the first child in the list, then get a reference to the parent... .
I found a work around.
"1234 " != "1234"! The DB may not notice this, but the EF does .
Be careful with the Char type.
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I have a problem with one-to-many relationships. I have the following domain classes:
public class Installation : Entity<Installation> { public virtual string Name { get; set; } public virtual IList<Institution> Institutions { get; set; } ...
Started by GUZ on
, 3 posts
by 3 people.
Answer Snippets (Read the full thread at stackoverflow):
When you have a persistent collection with inverse="true" , then the child object owns the relationship to the relationship whenever you....
The relationship and any changes to the parent's collection will be reflected in the database.
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Is there any way to set-up a symmetric self-join relationship mapping in NHibernate? Suppose we have two tables:
Users id Relations id user1 user2 relation_type
The User and Relation classes should look like this:
class User { public virtual int Id { ...
Started by svallory on
, 3 posts
by 3 people.
Answer Snippets (Read the full thread at stackoverflow):
relationship to Relation (eg a UserRelation table), rely on application code to enforce a 'two users per.
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I create some items from a class X.
I add them to de base, do SaveChanges and all this...
The class Y has a relationship many-to-many with X.
Using another Context, I create a Y instance, putting into the collection of X the elements I've created.
I add...
Started by Victor Rodrigues on
, 3 posts
by 3 people.
Answer Snippets (Read the full thread at stackoverflow):
[TestMethod] public void WorksWithAreaCategories() { using (new.
The relationship with Update.
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I have a pretty simple setup. To sum it up here's what I'm doing:
class Movie include MongoMapper::Document has_one :setting end class Setting include MongoMapper::EmbeddedDocument belongs_to :movie end
What I want to do is to update the setting of a ...
Started by marcgg on
, 3 posts
by 3 people.
Answer Snippets (Read the full thread at stackoverflow):
So, for example, this does work:
class Setting include MongoMapper::Document key :movie_id, ObjectId belongs_to :movie end class Movie include MongoMapper::Document... .
I'm pretty sure that has_one relationships aren't supported as embedded documents.
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I have the following problem in django.. I have in models.py
class Proposal(models.Model): #whatever.... credit =models.FloatField(null=True, blank=True) def save(): #here credit is saved based on some calculation (succesfully) class Author(models.Model...
Answer Snippets (Read the full thread at stackoverflow):
If the above method worked as you expected it to, you'd still have the problem of having to save an Author.
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