many-to-many

I did some research, and after reading this and this (and all the related questions) I still can't figure which is the proper way to update a many to many relationship in Symonfy 2 Doctrine. It feels that there should be a very simple way of doing it that I still haven't found. I have this 2 entities: class student_main { /** * @ORM\ManyToMany(targetEntity="support_log", inversedBy="student_main") * @ORM\JoinTable(name="support_log_student") **/ private $support_log; and class support_log { /** * @ORM\ManyToMany(targetEntity="student_main", mappedBy="support_log") **/ private $student; I want

I've created an Entity Framework model from the database. I have many-to-many relationship: User - UserRole - Role . EF created UserRole entity and UserRoles navigation property in the User entity and in Role entity, but I'd rather have Roles in User and Users in Role . Is that possible to be designed through the Model Designer? How can I configure manually many-to-many relationship with a table in the middle? EF normally creates the intermediate model, if the UserRole table comprises of columns other than foreign keys for User and Role table. So if you had just 2 columns in the UserRoles

One of my mongoose schemas is a many to many relationship: var UserSchema = new Schema({ name : String, groups : [ {type : mongoose.Schema.ObjectId, ref : 'Group'} ] }); var GroupSchema = new Schema({ name : String, users : [ {type : mongoose.Schema.ObjectId, ref : 'User'} ] }); If I remove a group, is there anyway to remove that group objectId from all the user's 'groups' array? GroupSchema.pre('remove', function(next){ //Remove group._id from all the users }) You're on the right track to use 'remove' middleware for this. In the middleware function, this is the group instance being removed

I have a M2M relationship between two Models which uses an intermediate model. For the sake of discussion, let's use the example from the manual: class Person(models.Model): name = models.CharField(max_length=128) def __unicode__(self): return self.name class Group(models.Model): name = models.CharField(max_length=128) members = models.ManyToManyField(Person, through='Membership') def __unicode__(self): return self.name class Membership(models.Model): person = models.ForeignKey(Person) group = models.ForeignKey(Group) date_joined = models.DateField() invite_reason = models.CharField(max_length

I have a class User. A user can be a friend with many other users. The relationship is mutual. If A is a friend of B then B is a friend of A. Also I want every relation to store additional data - for example the date when two users became friends. So this is a many-to-many relationship on the same table with additional columns. I know that a middle class Friendship should be created(containing two user ids and column for the date). But I am coming short at mapping this with Hibernate. The thing that stops me is that the mapping is to the same table. I can solve it, if the many-to-many

I'm trying to set up a SQLite3 database with foo s and bar s and a many-to-many relation between them. This is what I've got so far: CREATE TABLE foo( id INTEGER PRIMARY KEY NOT NULL, foo_col INTEGER NOT NULL ); CREATE TABLE bar( id INTEGER PRIMARY KEY NOT NULL, bar_col TEXT NOT NULL ); CREATE TABLE foobar( foo_id INTEGER, bar_id INTEGER, FOREIGN KEY(foo_id) REFERENCES foo(id) ON DELETE CASCADE, FOREIGN KEY(bar_id) REFERENCES bar(id) ON DELETE CASCADE ); CREATE INDEX fooindex ON foobar(foo_id); CREATE INDEX tagindex ON foobar(tag_id); ...but it doesn't seem to be working. I can delete a row

Suppose I have 2 tables in a database. eg: Dog & Boss This is a many to many relationship, cause a boss can have more than 1 dog, and a dog can have more than 1 owner. I am the owner of Bobby, but so is my wife. But many to many is not allowed, so there is a helpertable: DogsPerBoss How to model this in code? Class Boss can have a collection of Dogs. Class Dog can have a collection of Bosses. --> at least, that is what I think. Perhaps there are better solutions? How about extra data that is in the helper-table? Should that be in de Boss-class or in the Dog-class? eg: Nickname (I call the dog