one-to-many

I'm currently struggling with the right mapping annotations for a scenario using a composite Primary Key Class. First, what I am trying to achieve in words: I have 2 classes: group and FieldAccessRule. A Group can have many FieldAccessRules, while a FieldAccessRule only has ONE Group assigned. Modling this is not a problem so far (simplified): public class Group{ ... @OneToMany(mappedBy = "group") private Set<FieldAccessRule> fieldAccessRules; ... } and for the FieldAccessRule: public class FieldAccessRule { ... @ManyToOne @JoinColumn(name = "group_id") private Group group; ... } Now, I

So I am surprised that doing a search on google and stackoverflow doesn't return more results. In OO programming (I'm using java), how do you correctly implement a one-to-many relationship? I have a class Customer and class Job . My application is for a fictious company that completes jobs for customers. My current implementation is so that the Job class doesn't have anything to do with the Customer class, there is no reference to it at all. The Customer class uses a collection and methods to hold, retrieve and modify information about the Jobs that have been assigned by and/or completed for a

I have users, and users belong to a dealership. Upon user registration, I'm trying to save a new user, and a new dealership. User database has a dealership_id column, which I want to be populated with the ID of the newly created dealership. This is my current code in the UserController store method. public function store() { $user = new User(); $user->email = Input::get('email'); $user->password = Input::get('password'); $dealership = new Dealership(); $dealership->name = Input::get('dealership_name'); $user->push(); return "User Saved"; } Trying to use $user->push(); User data gets updated,

I am not able to describe my problem, I try it again with example: I have two entities (tables): Department and Person . Both tables have a field CODE which is not unique . How can I define manyToMany bidirectional relations between these tables? Departmen has collection Persons which returns all entities with Person.CODE eq Department.CODE Partner has collection Departments which returns all entities with Department.CODE eq Partner.CODE I need the relation definition - no sql or hpql query. --------- Original question ------- I need to create hibernate relation one to many between Department

What I would like to do is select a specific set of rows from one table (table A) and join with another table (table B), such that only one record will appear from table A, joined with the most recent record from table B, based on a datetime column. For example, table A has this structure (heavily simplified): id | col_1 | col_2 ---+-----------+---------------- 1 | something | something else 2 | val_1 | val_2 3 | stuff | ting 4 | goats | sheep And table B looks like this: id | fk_A | datetime_col | col_3 ---+-----------+---------------------+-------- 1 | 1 | 2012-02-01 15:42:14 | Note 1 2 | 1

I have a JPA setup in such a way that if I do not use lazy load, almost the entire database will be loaded. I also use serializing directly on the models so sometimes I need to initialize the proxies. I only want to use lazy load on the collections. The fact that some singular entities are fetched eagerly works just fine. But no matter how I try to setup the collections I never get a collection of proxies, I always get the fully loaded collection. This is some example code: @Entity public class Thread implements Externalizable { @OneToMany(mappedBy = "parentThread", fetch = FetchType.LAZY)