many-to-many

EF5 And cycles or multiple cascade paths, FOREIGN KEY

由 落爺英雄遲暮 提交于 2019-12-08 02:58:20
问题 I got a wierd problem, i already know about why normaly this exception happen and how to solve it by Disablaing WillCascadeOnDelete to False in one of the properties. But my problem seems to be other kind, Here is my code : Memeber : public class Memeber { public int MemberID { get; set; } public virtual ICollection<Message> SentMessages { get; set; } public virtual ICollection<Message> RecievedMessages { get; set; } } public class Message { public long MessageID { get; set; } public int

Select from many-to-many relationship sequelize

由 自古美人都是妖i 提交于 2019-12-08 02:05:43
问题 I tried to select from a table with reference another table. I have a relationship many-to-many between table food and table Ingredients. Food model: module.exports = function(sequelize, DataTypes) { return sequelize.define('food', { id: { type: DataTypes.INTEGER(10), allowNull: false, primaryKey: true, autoIncrement: true }, name_food: { type: DataTypes.STRING, allowNull: false } }, { tableName: 'food', freezeTableName: true }); }; Food_ingredients model: module.exports = function(sequelize,

How to I design a database constraint so two entities can only have a many to many relationship if two field values within them match?

由 风流意气都作罢 提交于 2019-12-08 00:21:25
问题 I have a database with four tables as follows: Addressbook -------------------- id more fields Contact --------------------- id addressbook id more fields Group --------------------- id addressbook id more fields Group to Contact --------------------- Composite key Group id Contact id My relationships are one to many for addressbook > contact, one to many for addressbook > group and many to many between contact and groups. So in summary, I have an addressbook. Contacts and groups can be

Django, Filter the set presented in a many to many modelform by currently logged in user

由 我们两清 提交于 2019-12-07 21:52:03
问题 I know it's there somewhere but I can't find it. So I have a 'category' model and a 'book' model which has a many to many to 'category'. When creating a new book in a modelform, all the categories are presented to the user to assign to the book. In that case I want only the categories created by the current user to show up in that field, not all the categories. What's the best approach? 回答1: Assuming your model like: class Category(models.Model): .... creator = models.ForeignKey(User) class

how to map Many to Many with composite key

由 那年仲夏 提交于 2019-12-07 19:18:23
问题 I have the following tables Trainingplan TrainingplanID int(11) AI PK Trainer int(11) Client int(11) validFrom date validTo date type int(11) TrainingplanExercises trainingplan int(11) PK exercise int(11) PK parameter int(11) PK value varchar(45) No I have problems connecting them with Hibernate. I did the following: package beans; @Entity @Table(name = "Trainingplan") public class Training { private IntegerProperty id; private ObjectProperty<Person> client; private ObjectProperty<Person>

NHibernate many-to-many mapping

由 半城伤御伤魂 提交于 2019-12-07 16:26:35
I am having an issue with many-to-many mapping using NHibernate. Basically I have 2 classes in my object model (Scenario and Skill) mapping to three tables in my database (Scenario, Skill and ScenarioSkill). The ScenarioSkills table just holds the IDs of the SKill and Scenario table (SkillID, ScenarioID). In the object model a Scenario has a couple of general properties and a list of associated skills (IList) that is obtained from the ScenarioSkills table. There is no associated IList of Scenarios for the Skill object. The mapping from Scenario and Skill to ScenarioSkill is a many-to-many

Symfony2 remove and save many to many relations

由 折月煮酒 提交于 2019-12-07 15:44:53
问题 I need your help today. I'm working on a small application using symphony 2.1 but I have a base problem, I have to tables with a many to many relation which creates a third table: class Usuario implements UserInterface { /** * @ORM\ManyToMany(targetEntity="Alood\BackBundle\Entity\Alergeno", inversedBy="usuarios") * @ORM\JoinTable(name="UsuariosProductos", * joinColumns={@ORM\JoinColumn(name="usuario_user", referencedColumnName="user")}, * inverseJoinColumns={@ORM\JoinColumn(name="alergeno_id"

SQL Server Query for Many to Many Relationship - how to query?

由 ◇◆丶佛笑我妖孽 提交于 2019-12-07 15:28:32
This is an update to my previous question : Many to many relationship The previous solution works fine, but now I want tgo improve the results a little bit. I´d like to have all the wavelength values in one row. So instead of the following result : DateTimeID Wavelength SensorID 11435 1581,665 334 11435 1515,166 334 11435 1518,286 335 I'd like to have something similar to this: DateTimeID Wavelength1 Wavelength2 SensorID 11435 1581,665 1515,166 334 11435 1518,286 335 You could use the following which applies a row_number() to the records: select DateTimeID, [1] as Wavelength1, [2] as

Code First Entity Framework Many-to-Many relationships

由 こ雲淡風輕ζ 提交于 2019-12-07 15:22:17
问题 Can someone point out where I've got wrong!! I have created 2 simple classes, with many-to-many relationship. Works fine, all the tables are populated correctly. Except when I try and retrive any Students courses nothing is returned... public partial class Student { public Student() { Courses = new HashSet<Course>(); } public int StudentID { get; set; } [StringLength(50)] [Required] public string FirstName { get; set;} [StringLength(50)] [Required] public string LastName {get; set;} public

Django admin: ManyToManyField in list_editable?

由 时间秒杀一切 提交于 2019-12-07 14:58:57
问题 In the Django admin, I would really like to be able to display an editable ManyToManyField in the list display. It doesn't necessarily need to be the full ManyToManyField control - being able to save just one value would be good enough for the purposes of the list display (though the underlying values are many-to-many in nature). My model looks like this: class Item(models.Model): name = models.CharField(max_length=500) colour = models.ManyToManyField(Colour, related_name='primary_colour') If
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