many-to-one | 易学教程

Updating oneToMany entity sets parent to null

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问题 I have a list of Role entities on a User entity linked with a @OneToMany relationship. When I change the list on the User entity, i.e change the roles, hibernate removes the old roles and adds the new ones as desired. However the foreign key field is set to null on the Role entity. Can you explian why the foregign key field is null, and how would I change it so it gets picked up on an update? User.java @SerializedName("userrole") @Expose @OneToMany(mappedBy = "user", fetch = FetchType.EAGER,

Odoo 9.0C: How can i access the value of a many2one field (that has been created in sale.order.line module on the invoice qweb report?

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问题 I have installed module Sale Sourced by Line by Camptocamp, Eficent, SerpentCS, Odoo Community Association (OCA) for Odoo 9.0. The module creates a new many2one field as the code bellow: class SaleOrderLine(models.Model): _inherit = 'sale.order.line' warehouse_id = fields.Many2one( 'stock.warehouse', 'Source Warehouse', readonly=True, states={'draft': [('readonly', False)], 'sent': [('readonly', False)]}, help="If a source warehouse is selected, " "it will be used to define the route. "

2 or more One to Many relationships between two tables in rails

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问题 I have two tables: Users and Groups a User has_many groups and a group, belongs_to a user: u = User.last u.groups Supposed I wanted a second list of different groups, for some strange reason. Where once again a User has may groups (called other_group in this example) and a group belongs to a User. u = User.last u.other_groups How do I associate two models in this relationship, Twice using Active Record? 回答1: You can do class User has_many :groups, :class_name => "Group", :foreign_key =>

NHibernate composite id mapping issue, bi/uni-directional OneToMany, ManyToOne and ManyToMany

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问题 In my project all of entities have composite primary keys [systemId as long, deviceId as long, id as long]. Values filled manualy before I save the entity. I'm using "code first" approach and to provide simplicity references NHibernate.Mapping.Attributes extension to define schema with attributes just like in Java based Hibernate. All entities have an abstract base type which provides shared properties and functionality: [Serializable] public abstract class EntityBase { [CompositeId(0, Name =

yii rewrite url with many sub categories

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问题 I'm working in yii with problem: I want to make an url like this: http://domainabc.com/catalog/cat1/cat2/cat3....?sort=name&limit=10&brand=.... It point to controller: CatalogController, action Index The url just say cat1 is parent, cat2 is parent of cat3. So in this action It just get products of the last category (cat3 for example) But currently I don't know what's the best way to get the last cat to get products. Error: "The system is unable to find the requested action 'cat1'" We must use

Relations function in AR Model, many to one relationship

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问题 So here's the scenario: I have two table, Issue & Project. A Project can have many Issue and an Issue can exactly one project. Since Issue is many to one, do you have to define it? Cause I know in Project Model I have: public function relations() { return array( 'issues' => array(self::HAS_MANY, 'Issue', 'project_id'), 'users' => array(self::MANY_MANY, 'User', 'tbl_project_user_assignment(project_id, user_id)'), ); } For Issue Model I have nothing but foreign keys: public function relations()

use the one-to-many or many-to-one

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问题 Two class: Department Task One department can have many tasks. One task can only belong to one department. So use one-to-many or many-to-one? one-to-many class Department{ private Set tasks; } class Task{ ...... } // Department.hbm.xml .... <set name="tasks"> <key column="departId" /> <one-to-many class="Task" /> </set> ..... many-to-one class Department{ } class Task{ Department depart; } // Task.hbm.xml .... <property name="depart"> <many-to-one class="Department" /> </property> ..... What

Two attributes sharing the same OneToMany relationship to one entity Symfony2

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问题 Let's first describe my situation. I am using Symfony2 and I have a problem with a relationship between my entities. I have two entities that are linked together. The two entities are AssociationQuestion and AssociationPossibleAnswer . I am currently creating a questionary software where one would have to link one possible answer on the left to another one possible answer on the right, such as in the following example: Currently, I'm planning on having two attributes that are arrays in class

Hibernate @ManyToOne remove entry at One side, set FK to NULL at Many side

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I'm trying to learn to work with Hibernate but probably i don't understand @ManyToOne and inverse relations. I have two entities Author and Department . One Author has one Department, One Department has Many Authors. When I remove Author, nothing should happen with Department. When I remove Department, FK in Author's table should be updated to NULL value (Author should NOT be removed). I've found nice explanation of inversion and figured out that Author is an owning side and according to this thread when I remove child (Department) the FK should be set to NULL . But it doesn't happen because

JPA unidirectional @OneToOne vs @ManyToOne with Hibernate - no difference?

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问题 According to book Pro JPA 2 the main difference between unidirectional @ManyToOne and @OneToOne is that in @OneToOne: Only one instance of the source entity can refer to the same target entity instance. In other words, the target entity instance is not shared among the source entity instances. In the database, this equates to having a uniqueness constraint on the source foreign key column (that is, the foreign key column in the source entity table). The thing is, when I create such a mapping