foreign-key-relationship Questions
2
Solved
I have two entities in my MVC application and I populated the database with Entity Framework 6 Code First approach. There are two city id in the Student entity; one of them for BirthCity, the other...
Cicatrix asked 17/2, 2015 at 20:54
1
Solved
I'd like to have a principal entity (Person) with optional dependent entity (Car) mapped using the default conventions in Entity Framework code-first model.
One solution is described in this answe...
Collard asked 10/1, 2015 at 10:53
2
Solved
I have some problems with JPA2 (EclipseLink) and Spring Data 1.4.2.
In my case two tables has one-to-one relation:
TableA:
aId (PK)
...
TableB:
bId (PK, FK - maps to aId in TableA)
...
so...
Luddite asked 22/11, 2013 at 16:6
1
Solved
Using Schema First, I have a database structure, as so
ExternalDataItems
---
edataitem_id PK -- surrogate auto-increment - NOT for FK relation here
datahash UX -- Candidate Key / Unique Index (bin...
Seow asked 18/12, 2014 at 19:3
1
Solved
I have just started internship at a small software house and I am working on an ERP. My team lead has forbidden me to create any relationships in the database. As this is my internship I was shocke...
Peduncle asked 3/12, 2014 at 16:30
2
Solved
I see this in a laravel tutorial :
Auth::user()->item;
where item is a function, inside models\User.php :
function item() { return $this->hasMany('Item', 'owner_id'); }
where Item is ...
Fraunhofer asked 22/10, 2014 at 16:17
5
Solved
Not sure if I'm reading this right, but it seems like Scaffold will not do a one-to-many relationship in its entirety. For instance, if I create messages with scaffold and then I want comments on t...
Lentiginous asked 2/2, 2009 at 3:37
2
Solved
Starting from an existing (SQLite) database with foreign keys, can SQLAlchemy automatically build relationships?
SQLAlchemy classes are automatically created via __table_args__ = {'autoload': True...
Ricotta asked 18/1, 2013 at 11:49
2
I have a local user model which uses activerecord. The user has an email field. I also have an activeresource model called tasks which has a created_by field which stores the submitting users email...
Staysail asked 17/6, 2014 at 8:43
1
Solved
In the SQLite documentation it says:
The parent key of a foreign key constraint is not allowed to use the
rowid. The parent key must used named columns only.
The parent key must be a named c...
Annunciation asked 2/6, 2014 at 20:16
3
Solved
I want a foreign key between 2 tables , so i try it like i always do. Now the issue i'm having is he fails to create , and by the looks of it it fails to create because there is already a key but t...
Recitative asked 4/7, 2012 at 7:35
1
Solved
I want a basic syntax of relation and their parameters
i need these clarification
Difference Between BELONGS_TO and HAS_ONE ?
I want to use the relation on CGridView (That relation refers the a...
Darla asked 6/9, 2013 at 13:3
2
Solved
I'm very new to databases and I'm a novice to data abstraction, coming from Java. To teach myself, I'm working on an online app that will, among other things, allow users to be part of multiple gro...
Tholos asked 5/5, 2014 at 15:48
1
When I try to delete Comany (model) with related objects, I get strange exception:
Object matching query does not exist when try to delete object
company = Company.objects.get(id=request.GET.get...
Dynamic asked 4/3, 2014 at 13:54
1
Solved
I have two classes: Artist and Instrument. Each Artist can play one or more Instruments. And each Instrument can be assigned to one or more Artists. So, I've set up the following Classes:
Artist.p...
Krucik asked 12/2, 2014 at 17:21
1
I have a database which contains around 50 tables.
Suppose I have a table named parent with id primary key and 24 approx child tables with reference to this parent table.
I haven't used on delete...
Constabulary asked 23/1, 2014 at 6:57
3
Solved
I want to find all foreign keys in my database that reference to a primary key of a certain table.
For example, I have a column A in table T which is the primary key. Now I want to find in w...
Suffragist asked 7/1, 2014 at 10:14
2
Solved
Suppose there is an abstract model CarOwner: whereas a Person or a Business can be a CarOwner. In addition a Car with a certain VIN can belong (relate) to either a Person or a Business, but not bot...
Stately asked 4/1, 2014 at 20:58
1
I am new to Backbone-relational, I am not sure what is the right way to use HasMany.
I have a Parent model which have many children (by "many" I mean thousands of children). In order to avoid perf...
Desquamate asked 11/4, 2013 at 16:46
2
Solved
While trying to add a foreign Key constraint to two very large tables, I get the error.
SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constr...
Insubordinate asked 5/12, 2013 at 4:47
1
I have two models (say, Supplier and Coffee) and Coffee model has foreign key reference to Supplier model. During ddl, I want this relationship to exist in table creation. But I also want to be abl...
Mufi asked 17/10, 2013 at 12:48
1
Solved
I'm tring to create a DbContext with my entites on entityframework5 codefirst way. I've brands, categories and products.
But when I try to get a Product it's Brand and Category fields are null. C...
Endocardium asked 22/9, 2013 at 14:57
2
Solved
I Have 3 Tables with foreign keys to each other.
I want to write a SQL Server Stored Procedure to select records from one of them.
Now, let's suppose that i want all the Winner records referring...
Obsequent asked 6/8, 2013 at 13:10
8
Solved
Customers
customer_id
Orders
order_id
customer_id fk
If I have two tables and define a foreign key on customer_id in the Orders table, by allowing it to be null I am saying that I can have an...
Ulyssesumayyad asked 29/5, 2009 at 9:42
1
Solved
Sorry for the nebulous title, it's hard to describe this in a single line:
I have 2 entities User and UserAddress, where User has 2 foreign keys DefaultInvoiceAddressId and DefaultDeliveryAddressI...
Lawful asked 30/7, 2013 at 8:26
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