one-to-many

One-to-many relationship in the same table

Hi, Im trying to use to define a one-to-many relationship in a single table. For example lets say I have a Groups table with these entries: Group: Group_1: name: Atlantic Records Group_2: name: Capital Records Group_3: name: Gnarls Barkley Group_4: name: Death Cab For Cutie Group_5: name: Coldplay Group...

PHP/mySQL - how to fetch nested rows into multidimensinal array

Coming from another question of mine where I learnt not to EVER use db queries within loops I consequently have to learn how to fetch all the data in a convenient way before I loop through it. Let's say I have two tables 'scales' and 'items'. Each item in items belongs to one scale in scales and is linked with a foreign key (scaleID). I...

What's the best way to save a one-to-many relationship in Linq2Sql?

Hi folks, I'm trying to figure out the best way to save a simple one-to-many relationship in Linq2Sql. Lets assume we have the following POCO model (pseduo code btw): Person has zero to many Vechicles. class Person { IList<Vehicle> Vehicle; } class Vehicle { string Name; string Colour; } Now, when i save a Person, i pa...

Filter a one-to-many query by requiring all of many meet criteria.

Imagine the following tables: create table boxes( id int, name text, ...); create table thingsinboxes( id int, box_id int, thing enum('apple,'banana','orange'); And the tables look like: Boxes: id | name 1 | orangesOnly 2 | orangesOnly2 3 | orangesBananas 4 | misc thingsinboxes: id | box_id | thing 1 | 1 | orange 2 | 1...

How to implement one-to-many relationships in Ibatis?

Let's say I have this Class: Class A { int id; int[] b; // Other properties } Class B { int id; // Other properties } The Class A has one-to-many relation with class B. I already have a service which caches B objects and return them on id. Table schema looks something like thi...

NHibernate one way, one-to-many, mapping question

Hi, I have a scenario in NHibernate where I have a one-to-many relationship between entities Employee and EmployeeStatus. Employee has properties eg: ID, Name and an IList of EmployeeStatus, whilst EmployeeStatus, for the purposes of this question, just has it's own ID and some free text. I don't need to hold a reference to Employee f...

PHP and outputting one-to-many results

I've only dealt with one-to-one relationships in php so far, but I'm stuck on a problem which involves a one-to-many relationship. I've been sitting on this for a few days with no luck, so I'm desperate for someone to step in and show me a solution before I lose my mind. In my database have a series of urls, which are received by a SELE...

How to eagerly fetch a single "default" entity from a collection in EJB3/JPA

I have a Person entity with multiple phone numbers. @OneToMany(mappedBy="person", cascade=CascadeType.ALL) public Set<PhoneNumberOfPerson> getPhoneNumbers() { return phoneNumbers; } Now I would like to implement a "get default phone number" method for Person that is eagerly fetched. This default phone number is one of the phone ...

NHibernate mapping trouble

Hello. I have the following object model: A top-level abstract class Element with many children and descendants. A class Event. Each Element contains a bag of Events. Each Event has a pointer to the parent Element. Up till now - pretty standart one-to-many relationship. But, I want to use table per concrete class strategy. So, t...

NHibernate one-to-many mapping problem

I have to map two simple table with a foreign key relationship. One of the tables is Contact containing columns id (primary key of type int),name, address and guid (newly added and is not the primary key). The other one is phone__number containing columns id (primary key of type int), contact___id (foreign key of id in contact table) and...

ASP.NET and a One-to-Many-to-Many Scenario

I'm new to ASP.NET but not to programming. I am migrating our current site from PHP/MySQL to ASP.NET(3.5)/SqlServer. I've been lurking here since the site's launch, so I'm confident that one (or more) of you can help me out. Here's the scenario: This is a training department site and the dept. has a course catalog stored in the table co...

How can I know the address of owner object in C++?

Hi, I would like to create in C++ a Notifier class that I will use in other objects to notify various holders when the object gets destroyed. template <class Owner> class Notifier<Owner> { public: Notifier(Owner* owner); ~Notifier(); // Notifies the owner that an object is destroyed }; class Owner; class Owned { public: Owned(...

Show a one to many relationship as 2 columns - 1 unique row (ID & comma separated list)

I need something similar to these 2 SO questions, but using Informix SQL syntax. http://stackoverflow.com/questions/37696/concatenate-several-fields-into-one-with-sql http://stackoverflow.com/questions/368459/sql-help-select-statement-concatenate-a-one-to-many-relationship My data coming in looks like this: id codes 63592 PE...

Ado.Net Entity : Object doesn't display linked members (foreign keys)

I have a simple databasescheme: User, Account. User has 1-to-many relationship with Account. I have generated a ado.net entity data model, and I can create users and accounts, and even link them together. In the database the account.user_id is correctly filled, so theoretically I should be able to acces User.Account.ToList() in C# throu...

nHibernate Null List Values on One-To-Many

I have an Order mapping with many OrderItems. The mapping correctly saves both the Order and OrderItems to the database when I do a save on just the Order, but when I reload that order, the List of OrderItems that the order contains is filled with null values (for all the othe order items in the table) until it reaches the OrderItem tha...

Can a junction table (join table) also be used for a one-to-many relationship?

According to the definition, a Junction Table (bridge table/link table) is used for many-to-many relationships, when used like this: CREATE TABLE Users ( UserLogin varchar(50) PRIMARY KEY, UserPassword varchar(50) NOT NULL, UserName varchar(50) NOT NULL ) CREATE TABLE Permissions ( PermissionKey varchar(50) PRIMARY KEY, PermissionDesc...

How to add many-to-one relationship in PostgreSQL

I having two table: Stock Master and Stock In, how do i create many-to-one relationship between them, Stock In record many different stock by different date and quantity, but Stock Master must showing and combine same stock with their quantity into one , and must functional first in first out. ...

SQL: Statement to show 1 child record per parent in a One-to-Many relationship

I have 2 tables, a product table and an image table. Products can have more than 1 image per record. I need an SQL statement that will list 1 image per product rather than all images per product. A scaled down example of my current effort is: SELECT Product.RefCode, Img.ImgPath FROM Product INNER JOIN ( SELECT ProductImg.ImgPath, ...

Map one-to-many tables relationship to a single entity framework object

I have the following tables in the database (just a demo, of course): Positions PositionId Limits LimitId PositionId I want to left join them into a single entity (always have position, not always have a limit attached to it): Position PositionId LimitId I've seen articles regarding one-to-one mapping and "Table per type inherit...

Hibernate - child collection Identifier changed in update

Hi guys, when I trying to update the object RFQ , Hibernate tends to update its child collection BQMaster and trying to set and update the identifier of BQMaster which normally it should not be allowed. The postgre log file: *2009-05-22 11:16:53 ERROR: duplicate key violates unique constraint "bq_masters_pkey"* *2009-05-22 11:16:53 STAT...