I have a class with multiple many to many relationships mapping to the same secondary class. My EquipmentSet class has two arrays of Equipment objects, and the Equipment class also has an array of EquipmentSets to determine which sets the equipment is a part of.
EF is only generating a lookup table for the second Many to Many relationship. How can I tell EF to generate lookup tables for both? When the code below is used, only the table "ModelSpecificEquipment" is generated. The table "GlobalEquipment" never gets generated.
public partial class EquipmentSet
{
public int Id { get; set; }
public List<Equipment> Global { get; protected set; }
public List<Equipment> ModelSpecific { get; protected set; }
public EquipmentSet()
{
Global = new List<Equipment>();
ModelSpecific = new List<Equipment>();
}
}
public partial class Equipment
{
public int Id { get; set; }
public List<EquipmentSet> EquipmentSets { get; set; }
public Equipment()
{
}
}
public class DataContext : DbContext
{
public DbSet<Equipment> Equipment { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Equipment>()
.HasMany<EquipmentSet>(x => x.EquipmentSets)
.WithMany(x => x.Global)
.Map(x =>
{
x.MapLeftKey("EquipmentId");
x.MapRightKey("EquipmentSetId");
x.ToTable("GlobalEquipment");
});
modelBuilder.Entity<Equipment>()
.HasMany<EquipmentSet>(x => x.EquipmentSets)
.WithMany(x => x.ModelSpecific)
.Map(x =>
{
x.MapLeftKey("EquipmentId");
x.MapRightKey("EquipmentSetId");
x.ToTable("ModelSpecificEquipment");
});
base.OnModelCreating(modelBuilder);
}
}
Again, at this point the database that EF creates only contains 3 tables: EquipmentSets, Equipments, ModelSpecificEquipments. GlobalEquipments is missing.
I think it is not possible to map this. You cannot relate two endpoints on one side to one single endpoint on the other side of a relationship. You will probably need something like this:
public partial class Equipment
{
public int Id { get; set; }
public List<EquipmentSet> GlobalEquipmentSets { get; set; }
public List<EquipmentSet> ModelSpecificEquipmentSets { get; set; }
public IEnumerable<EquipmentSet> EquipmentSets
{
get
{
return GlobalEquipmentSets.Concat(ModelSpecificEquipmentSets);
// catch cases when one or both of the sets are null.
}
}
}
EquipmentSets is here only a readonly helper which isn't mapped to the database.
You can then create a many-to-many relationship between Global and GlobalEquipmentSets and another many-to-many relationship between ModelSpecific and ModelSpecificEquipmentSets.
Related
I trying to create inheritance so I can have some super classes with general properties and then more specialized classes that are the ones getting used.
I want something like the Table per type or table per class they make here http://www.codeproject.com/Articles/232034/Inheritance-mapping-strategies-in-Fluent-Nhibernat
So I have my supertype Game here
public abstract class Game
{
public virtual int Id { get; set; }
public virtual List<UserGame> UserList { get; set; }
}
public class GameMap : ClassMap<Game>
{
public GameMap()
{
Id(x => x.Id, "GameId")
.GeneratedBy
.HiLo("100");
HasMany(x => x.UserList)
.Cascade.All();
}
}
And then my specialized class here QMGameActive
public class QMGameActive : Game
{
public virtual DateTime LastUpdate { get; set; }
public virtual string SelectedBrick { get; set; }
public virtual int Score { get; set; }
public virtual string History { get; set; }
public virtual int StartingPlayerId { get; set; }
public QMGameActive()
{
LastUpdate = DateTime.Now;
History = "";
SelectedBrick = "";
}
}
public class QMGameActiveMap : SubclassMap<QMGameActive>
{
public QMGameActiveMap()
{
KeyColumn("GameId");
Map(x => x.LastUpdate);
Map(x => x.SelectedBrick);
Map(x => x.Score);
Map(x => x.History);
Map(x => x.StartingPlayerId);
}
}
But when I get a diagram from the server I can see there is no connection between Game and QMGameActive there
So what am I missing to make it use inheritance?
I am fairly sure that if you KeyColumn("GameId"); from the QMGameActiveMap() then NHibernate will generate QMGameActive with an ID Column of GameID which will be a foreign key of Game.GameId. which would seem to give you what you want.
(sorry away from home and cannot try code out to make sure).
I am have some trouble getting Entity Framework to handle a many to many relationship in my data schema. Here is my model:
public class User
{
public int UserId { get; set; }
public int Username { get; set; }
public IEnumerable<Customer> Customers { get; set; }
...
}
public class Customer
{
public int CustomerId { get; set; }
...
}
public class CustomerUser
{
public int CustomerUserId { get; set; }
public int CustomerId { get; set; }
public int UserId { get; set; }
public DateTime CreatedTimestamp { get; set; }
...
}
Here is the mapping:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Entity<User>().HasKey(u => u.UserId).ToTable("Users");
modelBuilder.Entity<Customer>().HasKey(c => c.CustomerId).ToTable("Customer");
modelBuilder.Entity<CustomerUsers>().HasKey(cu => cu.CustomerUserId).ToTable("CustomerUsers");
modelBuilder.Entity<CustomerUsers>()
.HasRequired(cu => cu.User)
.WithRequiredDependent()
.Map(m =>
{
m.ToTable("Users");
m.MapKey("CustomerUsers.UserId");
});
}
My database has a Users, Customers, and CustomerUsers table with columns that match the model.
I am trying to execute the following query:
result = (from u in context.Users
join customerUsers in context.CustomerUsers on u.UserId equals customerUsers.User.UserId
join customers in context.Customers on customerUsers.CustomerId equals customers.CustomerId into ps
select new
{
User = u,
Customers = ps
}).ToList().Select(r => { r.User.Customers = r.Customers.ToList(); return r.User; });
When I run the code, I get the following error:
The Column 'CustomerUserId' specified as part of this MSL does not exist in MetadataWorkspace
Can anyone see what is wrong with my approach?
Thanks!
I should note that I am intentionally trying to not include a reference to the CustomerUsers table from either the Customer or User class. The majority of the time, the payload of the CustomerUsers table is not important, only which customers are associated to which users. There are some reporting scenarios where the additional information in the join table is necessary, but since this is not the typical situation, I would like to avoid cluttering up the models by having this additional indirection.
Instead of trying to map this as many to many, map it as two one to many relationships. See the discussion of many to many join tables with payload in Many-to-Many Relationships in this tutorial:
http://www.asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/creating-a-more-complex-data-model-for-an-asp-net-mvc-application
For your model you will need probably two one-to-many relationships and the following navigation properties:
public class User
{
public int UserId { get; set; }
public int Username { get; set; }
// ...
public ICollection<CustomerUser> CustomerUsers { get; set; }
}
public class Customer
{
public int CustomerId { get; set; }
//...
public ICollection<CustomerUser> CustomerUsers { get; set; }
}
public class CustomerUser
{
public int CustomerUserId { get; set; }
public int CustomerId { get; set; }
public int UserId { get; set; }
public DateTime CreatedTimestamp { get; set; }
//...
public User User { get; set; }
public Customer Customer { get; set; }
}
And the following mapping:
modelBuilder.Entity<CustomerUser>()
.HasRequired(cu => cu.User)
.WithMany(u => u.CustomerUsers)
.HasForeignKey(cu => cu.UserId);
modelBuilder.Entity<CustomerUser>()
.HasRequired(cu => cu.Customer)
.WithMany(c => c.CustomerUsers)
.HasForeignKey(cu => cu.CustomerId);
I'm trying to model a self-referencing many to many in EF CodeFirst with a polymorphic table structure. I'm using the October 2011 CTP which supports navigation properties on derived types (which works well in other tests I've done).
The problem:
When I set up this particular many to many relationship in the base (abstract) table's mapping and try to get related records, I get a SQL query with hundreds of K of unions and joins...just the time taken to generate the SQL statement is 30 seconds, compared to bare milliseconds to execute it. However, it does return appropriate results. When I change the many to many to exist between two derived objects, the query produced is perfect...but I can't map the same relating M2M table again for other derived objects without being informed that the joining table has "already been mapped".
Specifics:
An existing database structure has a base table--Party--which is joined 1...1 or 0 with Customer, Vendor, User, and Department (each a type of Party).
Parties are related to each other via an existing join table PartyRelationship (ID, InternalPartyID, ExternalPartyID). By convention, InternalPartyID contains a User's PartyID and ExternalPartyID contains the PartyID of the Customer, Vendor, or Department with which they are associated.
Trying to use EF CodeFirst in a new project (WCF DataServices), I have created the Party class as:
public abstract class Party
{
public Party()
{
this.Addresses = new List<Address>();
this.PhoneNumbers = new List<PhoneNumber>();
this.InternalRelatedParties = new List<Party>();
this.ExternalRelatedParties = new List<Party>();
}
public int PartyID { get; set; }
public short Active { get; set; }
//other fields common to Parties
public virtual ICollection<Address> Addresses { get; set; }
public virtual ICollection<PhoneNumber> PhoneNumbers { get; set; }
public virtual ICollection<Party> InternalRelatedParties { get; set; }
public virtual ICollection<Party> ExternalRelatedParties { get; set; }
}
Then, using TPT inheritance, Customer, Vendor, Department and User are similar to:
public class Customer : Party
{
public string TermsCode { get; set; }
public string DefaultFundsCode { get; set; }
//etc
}
public class User : Party
{
public string EmployeeNumber { get; set; }
public string LoginName { get; set; }
//etc
}
The joining table:
public class PartyRelationship
{
public int PartyRelationshipID { get; set; }
public int InternalPartyID { get; set; }
public int ExternalPartyID { get; set; }
//certain other fields specific to the relationship
}
Mappings:
public class PartyMap : EntityTypeConfiguration<Party>
{
public PartyMap()
{
// Primary Key
this.HasKey(t => t.PartyID);
// Properties
this.ToTable("Party");
this.Property(t => t.PartyID).HasColumnName("PartyID");
this.Property(t => t.Active).HasColumnName("Active");
//etc
// Relationships
this.HasMany(p => p.InternalRelatedParties)
.WithMany(rp => rp.ExternalRelatedParties)
.Map(p => p.ToTable("PartyRelationship")
.MapLeftKey("ExternalPartyID")
.MapRightKey("InternalPartyID"));
}
}
public class PartyRelationshipMap : EntityTypeConfiguration<PartyRelationship>
{
public PartyRelationshipMap()
{
// Primary Key
this.HasKey(t => t.PartyRelationshipID);
// Properties
// Table & Column Mappings
//this.ToTable("PartyRelationship"); // Commented out to prevent double-mapping
this.Property(t => t.PartyRelationshipID).HasColumnName("PartyRelationshipID");
this.Property(t => t.InternalPartyID).HasColumnName("InternalPartyID");
this.Property(t => t.ExternalPartyID).HasColumnName("ExternalPartyID");
this.Property(t => t.CreateTime).HasColumnName("CreateTime");
this.Property(t => t.CreateByID).HasColumnName("CreateByID");
this.Property(t => t.ChangeTime).HasColumnName("ChangeTime");
this.Property(t => t.ChangeByID).HasColumnName("ChangeByID");
}
}
Context:
public class MyDBContext : DbContext
{
public MyDBContext()
: base("name=MyDBName")
{
Database.SetInitializer<MyDBContext>(null);
this.Configuration.ProxyCreationEnabled = false;
}
public DbSet<Party> Parties { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Conventions.Remove<IncludeMetadataConvention>();
modelBuilder.Configurations.Add(new PartyMap());
modelBuilder.Configurations.Add(new PartyRelationshipMap());
}
}
A URL such as http://localhost:29004/Services/MyDataService.svc/Parties(142173)/SAData.Customer/InternalRelatedParties eventually returns correct oData but takes 30 seconds to produce an enormous SQL statement (189K) that executes in 600 ms.
I've also tried mapping the PartyRelationship table with a bidirectional one to many (both to Party as the "one" table), but with a similar outcome.
Do I need separate join tables for Customer-User, Vendor-User, and Department-User? Should I look at vertical table splitting or database views that separates PartyRelationship into separate logical entities (so I can remap the same table)? Is there another way the EF model should be configured in this scenario?
public class Purchase {
public Address to { get; set; }
public Address from { get; set; }
}
public class Address {
public string name { get; set; }
}
I have 1 Purchase with 2 Address. How this should be on the Database (mySql) including foreign keys to be used on Entity Framework.
I have the problem that entity understands (based on fk) that Navigability in Address is 1 to many (*) and I don't have a list of Address on Purchase, i have defined 2.
Thanks,
Bart.
You can configure relationships of the tables.Build your model like this,
public class PurchaseConfiguration : EntityTypeConfiguration<Purchase >
{
public PurchaseConfiguration()
{
HasRequired(p=>p.to ).WithOptionalDependent().WillCascadeOnDelete(false);
HasRequired(p => p.from ).WithOptionalDependent().WillCascadeOnDelete(false);
}
}
and your db context you can add the configurations like this,
public class yourDbContext:DbContext
{
public DbSet<Purchase> Purchases{ get; set; }
public DbSet<Address> Addresses{ get; set; }
//other db sets here..
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Configurations.Add(new PurchaseConfiguration ());
// you can add configurations for other tables
}
}
Using Entity Framework 4 and code first how would I create a model that supports this scenario:
In an application, there are users, each user belongs to one or more groups and for each group the user can have one or more roles.
Example:
I would like to be able to say, "give me Lisa", and the response returns a user object for lisa, with the groups she belongs to. For each group there is a list property with all the roles she has for that particular group
Can anyone help me model this using code first, any help/code samples, would be great!
/Best regards Vinblad
Edit: Here is new model for your requirement.
public class User
{
public virtual int Id { get; set; }
public virtual ICollection<UserPermission> Permissions { get; set; }
}
// Permission is extended junction table to model M:N between
// User and Group but in addition it contains relation to Roles.
// The ony disadvantage is that this model doesn't control that
// role in the collection is also the role related to group. You
// must either enforce it in application logic or create some additional
// database construct to check it.
public class UserPermission
{
public virtual int UserId { get; set; }
public virtual int GroupId { get; set; }
public virtual Group Group { get; set; }
public virtual ICollection<Role> Roles { get; set; }
}
public class Group
{
public virtual int Id { get; set; }
public virtual ICollection<UserPermission> UserPermissions { get; set; }
public virtual ICollection<Role> Roles { get; set; }
}
public class Role
{
public virtual int Id { get; set; }
public virtual ICollection<Group> Groups { get; set; }
public virtual ICollection<UserPermission> UserPermissions { get; set; }
}
public class Context : DbContext
{
public DbSet<User> Users { get; set; }
public DbSet<Group> Groups { get; set; }
public DbSet<Role> Roles { get; set; }
public DbSet<UserPermission> UserPermissions { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
// Permission has composite key
modelBuilder.Entity<UserPermission>()
.HasKey(p => new {p.UserId, p.GroupId});
// Permission doesn't have navigation property to user
modelBuilder.Entity<User>()
.HasMany(u => u.Permissions)
.WithRequired()
.HasForeignKey(p => p.UserId);
modelBuilder.Entity<Group>()
.HasMany(g => g.UserPermissions)
.WithRequired(p => p.Group)
.HasForeignKey(p => p.GroupId);
}
}
As described in code there is small disadvantage. You can avoid the disadvantage by enforcing data integrity in DB by additional FK which can't be modeled by code first. You can use custom initializer to add that FK:
public class CustomInitializer : DropCreateDatabaseIfModelChanges<Context>
{
protected override void Seed(Context context)
{
context.Database.ExecuteSqlCommand(
#"ALTER TABLE [dbo].[RoleUserPermissions]
WITH CHECK ADD CONSTRAINT [FK_RoleUserPermissions_RoleGroups]
FOREIGN KEY([Role_Id], [UserPermission_GroupId])
REFERENCES [dbo].[RoleGroups] ([Role_Id], [Group_Id])");
}
}
Just add this to your application initialization (only for debug - application should not be able to drop its database in release):
Database.SetInitializer(new CustomInitializer());