Develop Reference

Automapper Collection

I'm working on a project and I need to map collections. I came across Automapper.Collection and am trying to user the class but its all not working. Please I need help. Here is my code.
In my startup class
services.AddAutoMapper(cfg => { cfg.AddCollectionMappers(); },typeof(Startup));
I also created a class that Inherits from the Automapper Profile class here
public class UserMappingProfile : Profile
{
public UserMappingProfile()
{
CreateMap<PhotoToUpdateDto, Photo>().EqualityComparison((src, dest) => src.PublicId.ToLower() == dest.PublicId.ToLower());
CreateMap<SocialHandles, SocialHandleDto>().ReverseMap().EqualityComparison((src, dest) => src.Name.ToLower() == dest.Name.ToLower());
}
}
Anytime I use the mapper, it creates new records in the database instead of updating the already existing. Please I need help.

I think its because of navigation property in your entity
If you have navigation property ignore them in your Createmap
For example
CreateMap<PhotoToUpdateDto, Photo>().EqualityComparison((src, dest) =>
src.PublicId.ToLower() == dest.PublicId.ToLower())
.ForMember(p => p.Photographer , opt => opt.Ignore());

I'll assume this:
You have no problem with the mapper (since it still map your object successfully).
When you get new object to interact with database, a new record created, since your make sure the id mapping was correct.
You are using EF Core or some kind of ORM to interact with the database
If i was wrong, please just ignore this answer.
Okay, If my assuming was right, that's because automapper always return a new object as result of the mapping process, which is absolutely not tracked by your DbContext yet. And then, whenever you interact with that to make some change in the database, an add operation is likely going to happen.
I think you need to add some more information about the block of code that you actually have problem with... which in this case... why the database entry keep created, but not update.

Entity Framework issues - appends a "1" to my table name?

I have the following model-first (is that what it's called?) diagram that I have made. I use T4 to generate the classes.
Now, I have a problem that causes Entity Framework to somehow append a "1" to the table name of the DatabaseSupporter entity. The database has been generated from this very model, and nothing has been modified.
I am trying to execute the following line:
_entities.DatabaseSupporters.SingleOrDefault(s => s.Id == myId);
The error I receive when executing that line (along with its inner exception below) is:
An exception of type
'System.Data.Entity.Core.EntityCommandExecutionException' occurred in
mscorlib.dll but was not handled in user code.
Invalid object name 'dbo.DatabaseSupporter1'.
I tried fixing the problem with the following Fluent API code (notice the second line in the function that names the table explicitly to "DatabaseSupporter"), but with no luck.
protected override void OnModelCreating(System.Data.Entity.DbModelBuilder modelBuilder)
{
modelBuilder
.Entity<DatabaseSupporter>()
.HasOptional(f => f.DatabaseChatSession)
.WithOptionalPrincipal(s => s.DatabaseSupporter);
modelBuilder
.Entity<DatabaseSupporter>()
.Map(m =>
{
m.Property(s => s.Id)
.HasColumnName("Id");
m.ToTable("DatabaseSupporter");
});
modelBuilder
.Entity<DatabaseSupporter>()
.HasMany(s => s.DatabaseGroups)
.WithMany(g => g.DatabaseSupporters)
.Map(m =>
{
m.ToTable("DatabaseSupporterDatabaseGroup");
m.MapLeftKey("DatabaseGroups_Id");
m.MapRightKey("DatabaseSupporters_Id");
});
modelBuilder
.Entity<DatabaseGroup>()
.HasRequired(g => g.DatabaseChatProgram)
.WithMany(c => c.DatabaseGroups);
modelBuilder
.Entity<DatabaseGroup>()
.HasRequired(g => g.DatabaseOwner)
.WithMany(o => o.DatabaseGroups);
modelBuilder
.Entity<DatabaseOwner>()
.HasMany(o => o.DatabaseChatSessions)
.WithRequired(o => o.DatabaseOwner);
base.OnModelCreating(modelBuilder);
}
It should be mentioned that the Id property for every entity actually is a Guid.
I am using Entity Framework 6.0.2.
Any ideas?
Edit 1
Here's the generated DatabaseSupporter.cs file containing my DatabaseSupporter entity as requested in the comments.
//------------------------------------------------------------------------------
// <auto-generated>
// This code was generated from a template.
//
// Manual changes to this file may cause unexpected behavior in your application.
// Manual changes to this file will be overwritten if the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------
namespace Coengage.Data.Entities
{
using System;
using System.Collections.Generic;
public partial class DatabaseSupporter
{
public DatabaseSupporter()
{
this.DatabaseGroups = new HashSet<DatabaseGroup>();
}
public bool IsActive { get; set; }
public string Username { get; set; }
public System.Guid Id { get; set; }
public virtual DatabaseChatSession DatabaseChatSession { get; set; }
public virtual ICollection<DatabaseGroup> DatabaseGroups { get; set; }
}
}
Edit 2
The errors started occuring after I added the many-to-many link between DatabaseSupporter and DatabaseGroup. Before that link, the Fluent code wasn't needed either.

This mapping is incorrect:
modelBuilder
.Entity<DatabaseSupporter>()
.Map(m =>
{
m.Property(s => s.Id)
.HasColumnName("Id");
m.ToTable("DatabaseSupporter");
});
It is kind of 50 percent of a mapping for Entity Splitting - a mapping that stores properties of a single entity in two (or even more) separate tables that are linked by one-to-one relationships in the database. Because the mapping is not complete you even don't get a correct mapping for Entity Splitting. Especially EF seems to assume that the second table that contains the other properties (that are not explicitly configured in the mapping fragment) should have the name DatabaseSupporter1. I could reproduce that with EF 6 (which by the way has added a Property method to configure single properties in a mapping fragment. In earlier versions that method didn't exist (only the Properties method).) Also the one-to-one constraints are not created correctly in the database. In my opinion EF should throw an exception about an incorrect mapping here rather than silently mapping the model to nonsense without exception.
Anyway, you probably don't want to split your entity properties over multiple tables but map it to a single table. You must then replace the code block above by:
modelBuilder.Entity<DatabaseSupporter>()
.Property(s => s.Id)
.HasColumnName("Id");
modelBuilder.Entity<DatabaseSupporter>()
.ToTable("DatabaseSupporter");
The first mapping seems redundant because the property Id will be mapped by default to a column with the same name. The second mapping is possibly also redundant (depending on if table name pluralization is turned on or not). You can try it without this mapping. In any case you shouldn't get an exception anymore that complains about a missing dbo.DatabaseSupporter1.

I have replicated your model exactly as you have listed it and I cannot currently reproduce your issue in the DDL that the EDMX surface emits when Generating Database from Model.
Could you please provide detailed information on exactly how you are going about adding your many-to-many relationship between DatabaseGroup and DatabaseSupporter? You say that you're trying to add the relationship on the edmx surface and NOT through code and it craps on your table name?
I added this thing Many-to-many from DatabaseGroup to DatabaseSupporter
I added this thing Many-to-many from DatabaseSupporter to DatabaseGroup
Can you please provide the following:
Rollback to your codebase prior to adding the many-to-many relationship. Ensure that your EF Fluent API code is not currently in your project.
Generate the DDL from this surface and confirm that it is not being
generated with the name DatabaseSupporters1 (Post the tablename that
it chooses at this stage. DatabaseSupporter or DatabaseSupporters)
Now, right click DatabaseGroup| Add New| Association
Choose DatabaseGroup for the left and DatabaseSupporter for the
right. Confirm that the name of the association that the designer
chooses is DatabaseGroupDatabaseSupporter [Do not create]
Choose DatabaseSupporter for the left and DatabaseGroup for the
right. Confirm that the name of the association that the designer
chooses is DatabaseSupporterDatabaseGroup [Create]
From the edmx surface, right click the many-to-many association just created and click "Show in Model Browser"
Edit your post to include the settings that display.
Also, right click the surface and click "Generate Database from Model."
Edit your post to include the DDL that gets generated. The table
should be named [DatabaseSupporters]
(My first inclination is that it's going to have something to do with your navigation properties, but not entirely sure. I actually had Entity Framework do the same thing to me in a toy project I was working on but I recall it being trivial to correct and I don't recall what the root cause was; I seem to recall it being something about the nav properties)
[Edit]
Wait.....
If I remove the many-to-many that doesn't fix my problem. However,
reverting to before I added the many-to-many fixes it. The exact code
that throws the exception is already shown. If I remove my fluent
mappings entirely, it's not the same exception being thrown (it throws
something about a group and a supporter, and a principal). I have not
tried recreating the model in an empty project - that takes a lot of
time. I already tried searching the EDMX in Notepad for references -
none were found.
(note my added emphasis)
So the DatabaseSupporter1 error showed up after you tried your fluent api patch? Get rid of the patch, add the many-to-many and give us the real error then.
...also, it took me 5 minutes to build this diagram. I wouldn't qualify that as "a lot of time."

I don't have my dev environment here in front of me, but my immediate thoughts are:
FIRST
Your fluent looks ok - but is the plural s in your ID column correct? And no plural (s) on the table names? This would be the opposite of convention.
SECOND
EF will automatically append a number to address a name collision. See similar question here: Why does EntityFramework append a 1 by default in edmx after the database entities?
Any chance you have something hanging around - a code file removed from your solution but still in your build path? Have you tried searching your source folder using windows explorer rather than the visual studio?

modelBuilder
.Entity<DatabaseSupporter>()
.HasMany(s => s.DatabaseGroups)
.WithMany(g => g.DatabaseSupporters)
.Map(m =>
{
m.ToTable("DatabaseSupporterDatabaseGroup");
m.MapLeftKey("DatabaseGroups_Id");
m.MapRightKey("DatabaseSupporters_Id");
});
Left and Right are inversed on Many to Many.
Try this :
modelBuilder
.Entity<DatabaseSupporter>()
.HasMany(s => s.DatabaseGroups)
.WithMany(g => g.DatabaseSupporters)
.Map(m =>
{
m.ToTable("DatabaseSupporterDatabaseGroup");
m.MapLeftKey("DatabaseSupporters_Id");
m.MapRightKey("DatabaseGroups_Id");
});

I think the DatabaseSupporter class created two time
one name is : DatabaseSupporter
another one is : DatabaseSupporter1
The modified changes are stored in DatabaseSupporter1 and mapping to here.
You need to copy the DatabaseSupporter1 class code and past the code to DatabaseSupporter class . then delete this DatabaseSupporter1 class.

I had this issue from renaming tables in the diagram, specifically changing just the capitalization.
If you rename a table by clicking on the header in the diagram, I think it checks the entity set name before trying to change it, sees it exists (even though it's the same entity set), and appends a 1.
However, if you right-click and open the Properties pane and first rename the Entity Set Name, then change the Name second, it won't add the number.

In my case i have two tables in the same database with the same name (2 different schemas(see image)

How can do I use fluent nhibernate to map this relationship?

I have the following database tables:
Project table
Dependency table with columns (Id, ProjectId, DependentProjectId)
on my Project domain object i have the following mapping to be able to take a project and read its dependencies
public virtual IList<Dependency> Dependencies { get; set; }
HasMany(x => x.Dependencies).AsBag().Inverse().Cascade.AllDeleteOrphan().Fetch.Select().BatchSize(80);
I now want to create another property on the Project object to read all of the items where it is the dependent project (to find out the list of projects that has "me" as a dependency.
what is the correct way to do that mapping in fluent nhibernate?

I'd say you would just have to specify the .KeyColumn for the one to many relation, e.g.
HasMany(x => x.Dependencies)....KeyColumn("ProjectId")
HasMany(x => x.DependentProjects)....KeyColumn("DependentProjectId")

Fluent NHibernate attempting to delete collection with bi-directional reference

I'm using Fluent to map a parent collection -> child collection scenario for a framework demo I'm doing, I'm a bit of an NHibernate newbie so go easy :)
I have the following mappings for my DTOs:
public class OrderMapping : ClassMap<OrderDTO>
{
public OrderMapping()
{
Id(x => x.OrderId);
Map(x => x.OrderDate);
Map(x => x.Address);
HasMany<OrderLineDTO>(x => x.OrderLines).KeyColumn("OrderId").Not.LazyLoad();
Table("`Order`");
}
}
and
public class OrderLineMapping : ClassMap<OrderLineDTO>
{
public OrderLineMapping()
{
Id(x => x.OrderLineId);
Map(x => x.OrderId).ReadOnly();
Map(x => x.Amount);
Map(x => x.Description);
References<OrderDTO>(x => x.Order).Column("OrderId");
Table("OrderLine");
}
}
The DTO objects are set up to receive these values, and this all works fine (I've turned off LazyLoad for the child for now as I'm working on the framework and LazyLoading isn't finished).
So I open my test app - the data is loaded into two grids, with the parent and the children showing correctly
If I make changes to the child or parent object and attempt to save, I can see that the SQL generated for the parent/child save is correct and the values passed to the SQL are spot on - the only issue is that after the updates, NHib decides it wants to delete the collection? It attempts this SQL:
UPDATE OrderLine SET OrderId = null WHERE OrderId = 2
Which fails because the table has a FK from OrderLine to Order on OrderLine.OrderId = Order.OrderId with no cascade. Plus I don't understand why the collection requires a delete..
NHib throws a 'could not delete collection' error - is this because it's trying to delete the 'Order' reference from the OrderLineDTO child?
Edit:
Actually looking at the DTO it looks like on the reverse mapping from my business objects that 'Order' is not included on each OrderLineDTO so I've probably worked this out already! Hate it when I do that :)
Edit 2:
Turns out that even when correctly re-creating the object on the server side I get the same issue
any ideas?

Figured it out - RTFM :P
In the manual:
Very Important Note: If the column of a association is declared NOT NULL, NHibernate may cause constraint violations when it creates or updates the association. To prevent this problem, you must use a bidirectional association with the many valued end (the set or bag) marked as inverse="true". See the discussion of bidirectional associations later in this chapter.

Fluent NHibernate Many-to-many mapping with auto-generated pk instead of composite key

I'm working on a RoleProvider in .NET, using Fluent NHibernate to map tables in an Oracle 9.2 database.
The problem is that the many-to-many table connecting users and roles uses a primary key generated from a sequence, as opposed to a composite key. I can't really change this, because I'm writing it to be implemented in a larger existing system.
Here is my UserMap:
public UserMap()
{
this.Table("USR");
HasMany(x => x.Memberships).Cascade.All()
.Table("MEMBERSHIP").Inverse().LazyLoad();
HasManyToMany(x => x.Roles)
.Table("USR_ROLE")
.Cascade.SaveUpdate()
.ParentKeyColumn("USR_ID")
.ChildKeyColumn("ROLE_ID")
.Not.LazyLoad();
}
And my RoleMap:
public RoleMap()
{
this.Table("ROLE");
Map(x => x.Description).Column("ROLE_NAME");
Map(x => x.Comment).Column("ROLE_COMMENT");
HasManyToMany(x => x.Users)
.Table("USR_ROLE")
.ParentKeyColumn("ROLE_ID")
.ChildKeyColumn("USR_ID")
.Inverse();
}
Yet, this is giving me the error:
Type 'FluentNHibernate.Cfg.FluentConfigurationException' in assembly 'FluentNHibernate, Version=1.0.0.593, Culture=neutral, PublicKeyToken=8aa435e3cb308880' is not marked as serializable.
Is there a simple fix to allow this HasMayToMany to use my PersistentObjectMap extension? I'm thinking I may have to add a convention for this many-to-many relationship, but I don't know where to start with that, since I've just started using NHibernate and Fluent NHibernate only recently.
I've been working on this problem for a while and I can't seem to find a solution.
Any help would be much appreciated. Thanks.
EDIT: I think I've found a possible solution here: http://marekblotny.blogspot.com/2009/02/fluent-nhbernate-and-collections.html
I'll try the above method of creating an entity and a class map for the linking table and post my findings.
EDIT 2: I created a linking entity as mentioned in the above blog post and downloaded the newest binaries (1.0.0.623).
This helped me discover that the issue was with setting lazy load and trying to add roles to the user object in a completely new session.
I modified the code to move OpenSession to the BeginRequest of an HttpModule as described here. After doing this, I changed my data access code from wrapping the open session in a using statement, which closes the session when it is finished, to getting the current session and wrapping only the transaction in a using statement.
This seems to have resolved the bulk of my issue, but I am now getting an error that says "Could not insert collection" into the USR_ROLE table. And I'm wondering if the above code should work with a UserRoleMap described as:
public UserRoleMap()
{
this.Table("USR_ROLE");
/* maps audit fields id, created date/user, updated date/user */
this.PersistentObjectMap("USR_ROLE");
/* Link these tables */
References(x => x.Role).Column("ROLE_ID");
References(x => x.User).Column("USR_ID");
}
Hibernate's documentation for many-to-many relationship suggests creating an object to maintain a one-to-many/many-to-one, as in an ERD. I'm sure this would be much easier with conventional naming standards, but I have to stick with certain abbreviations and odd (and not always properly-implemented) conventions.

To fix this, I created an Entity, Mapping, and Repository for UserRole. And, instead of HasManyToMany mapping in the User and Role Entities, I have a HasMany mapping. It's a little weird, because I now have:
IList<UserRole> UserRoles {get; protected set;}
and IList<Role> Roles { get{ return UserRoles.Select(u => u.Role).ToList(); } }
This works, however, I'm not 100% sure why this works and the HasManyToMany doesn't.