one-to-many

问题 Here's the basic mapping: Client { @OneToMany(mappedBy="client",cascade=CascadeType.ALL, fetch=FetchType.EAGER) private Set<Group> groups = new HashSet<Group>(); } Group { @ManyToOne (cascade=CascadeType.ALL) private Client client = new Client(); } The problem I'm having is that when I query against Client, I'm getting a full client for each associated group. My queries are pretty simple and I've tried both criteria and HQL. Here's a sample criteria query: Criteria crit = getSession()

问题 I have the following two classes, one ReqCandAssociation can have many Comments and it is mapped like so. I need to figure out a way that when I delete a ReqCandAssociation it deletes all of its associated comments. Thanks @Entity @Table(name = "candidate_jobReq") public class ReqCandAssociation implements Serializable { @Id private Integer candidateId; @Id private Integer jobId; @Column(name = "reqStatus") private String reqStatus; @ManyToOne @PrimaryKeyJoinColumn(name="candidateId",

问题 I have a access table with Orders and a sub-table with itemId's. It has one to many relationship. I want to create a form that adds itemId's to a selected order(already existing). This is how i expect it to look like: Order: [ ] ItemId: [ ] Measurement1: [ ] Measurement2: [ ] [Save-button] Can anyone help me with this? 回答1: Subforms are the politically correct way to go IF you want users to have access to the order screen. If users do not need access to the order details directly, only to

问题 I am Working on ASP.NET MVC 5, EF 6, Razor Engine, VB Language and Database First Approach with VS 2013. Now, in my DB; I have two tables as below: CREATE TABLE [dbo].[Group] ( [Id] INT NOT NULL PRIMARY KEY IDENTITY(1, 1), [Name] VARCHAR(50) NOT NULL ) and CREATE TABLE [dbo].[Subscriber] ( [Id] INT NOT NULL PRIMARY KEY IDENTITY(1, 1), [FirstName] [nvarchar](100) NOT NULL, [MiddleName] [nvarchar](100) NULL, [LastName] [nvarchar](100) NOT NULL, [Email] [varchar] (200) NOT NULL UNIQUE, [GroupId]

问题 I'm facing the same situation as in this question, that has no useful answer. When I add a new element to the many part of my one-to-many relation, Hibernate generates two queries, one to insert and one to update the foreign key to the parent. Why does it need the second query for? Isn't the parent's id set in the insert? Is there any way of avoiding this? Hibernate: /* insert mydomain.LanguageKnowledge */ insert into languageKnowledge (language_fk, level_fk, personId_fk) values (?, ?, ?)

问题 Two Entities: Notification User User has an attribute called username There is one-to-many relationship between User <<---> Notification called "users" There is a Notification object (ObjectA) saved that has (2) User Objects saved in the "users" relationship. I would like to update ObjectA by deleting one of the User object in "users" relationship. User entity has an attribute called "username". There are (2) User' s with username "UserA" & "UserB" as objects in the "users" relationship, how

问题 I am using Backand BaaS for my ionic app. My model consists of two tables: 1. Users 2. Trips A one-to-many relationship has been established between 'Users' and 'Trips'. 'Users' has a collection field that is a collection of 'Trips' and 'Trips' has a owner field that is an object of 'Users'. What is the correct way to create an object so that upon creating I am assigning the correct owner ('Users' object) to 'Trips' collection field ? 回答1: When POSTing a new Trip use this for the Trip Object

问题 I am new to Core Data and objective-c. I am working on a project where I am taking JSON data from a web service and syncing it with core data. I successfully followed this tutorial and am able to get the JSON into core data without any problem. Where I am having trouble is updating the NSSet associated with a to-many relationship. So far I can get it to update but in doing so its creating duplicate entries in the set. For example, I tried using the Xcode generated access method in my custom

问题 I have two tables, DVD and Contact. A DVD can be rented to a contact and a contact can rent many DVD's. The many to one link (dvd-->contact) works fine. But the other way fails: (contact-->dvd) This is the contact mapping: <set name="dvds" inverse="true"> <key column="contactId"/> <one-to-many class="Dvd"/> </set> Here is setter getter for Contact: private Set<Dvd> dvds = new HashSet<Dvd>(); public Set<Dvd> getDvds(){ return dvds; } public void setDvds(Set<Dvd> dvds){ this.dvds=dvds; } When I

问题 I have the following in linq-to-entities clientprojects = (from p in this.SAPMappingEntities.SAP_Master_Projects join c in this.SAPMappingEntities.SAP_Master_ProjectPartners on c.project_no equals p.project_no where c.partner_name.Contains(clientstring) orderby p.start descending select new ClientProjects { client = c.partner_name, location = c.city +", "+c.region, project_no = c.project_no, start_dt = p.start, end_dt = p.finish }).Take(50).ToList(); I would like change this query so that for