many-to-many

Below is my model: public class TMUrl { //many other properties //only property with type Keyword public List<Keyword> Keywords{get;set;} } public class Keyword { //many other properties //only property with type TMUrl public List<TMUrl> Urls{get;set;} } So clearly, both the entities have many-to-many relationship. I chose fluent api to tell the entity-framework about this relationship i.e. modelBuilder.Entity<TMUrl> .HasMany(s => s.Keywords) .WithMany(s => s.URLs).Map(s => { s.MapLeftKey("KeywordId"); s.MapRightKey("UrlId"); s.ToTable("KeywordUrlMapping"); }); but when I do url.Keywords.Add

I'm trying to create a messaging system where a message's sender and recipients can be generic entities. This seems fine for the sender, where there is only object to reference (GenericForeignKey) but I can't figure out how to go about this for the recipients (GenericManyToManyKey ??) Below is a simplified example. PersonClient and CompanyClient inherit attributes from Client but have their own specific details. The last line is the sticking point. How do you allow message recipients to be a set of CompanyClients and PersonClients class Client(models.Model): city = models.CharField(max_length

Using the following related models (one blog entry can have multiple revisions): class BlogEntryRevision(models.Model): revisionNumber = models.IntegerField() title = models.CharField(max_length = 120) text = models.TextField() [...] class BlogEntry(models.Model): revisions = models.ManyToManyField(BlogEntryRevision) [...] How can I tell Django to delete all related BlogEntryRevision s when the corresponding BlogEntry is deleted? The default seems to be to keep objects in a many-to-many relation if an object of the "other" side is deleted. Any way to do this - preferably without overriding

I have the following tables Essence , EssenseSet , and Essense2EssenceSet Essense2EssenceSet is the linking table that creates the M:M relationship. I've been unable to get the M:M relationship working though in EF code first though. Here's my code: [Table("Essence", Schema = "Com")] public class Essence { public int EssenceID { get; set; } public string Name { get; set; } public int EssenceTypeID { get; set; } public string DescLong { get; set; } public string DescShort { get; set; } public virtual ICollection<EssenceSet> EssenceSets { get; set; } public virtual EssenceType EssenceType { get;

I'm triyng to understand how the many to many relationship works with Doctrine and Symfony2. I've recreated the example shown in the official documentation (goo.gl/GYcVE0) and i have two Entity Classes: User and Group as you can see below. <?php /** @Entity **/ class User { // ... /** * @ManyToMany(targetEntity="Group", inversedBy="users") * @JoinTable(name="users_groups") **/ private $groups; public function __construct() { $this->groups = new \Doctrine\Common\Collections\ArrayCollection(); } // ... } /** @Entity **/ class Group { // ... /** * @ManyToMany(targetEntity="User", mappedBy="groups