I have a situation where i have defined an entity in my domain model in which I would like to expose a single id column.
public class OfferedProduct
{
public virtual string Id {get; set;}
//other properties
}
The legacy database table this will map to is
CREATE TABLE ProductGrouping
MemberNumber INT NOT NULL,
GroupId CHAR NOT NULL,
...
I dont want to compromise the domain model by introducing two properties and mapping them using the "CompositeId" construct.
CompositeId().KeyProperty(x => x.MemberNumber).KeyProperty(x => x.GroupId)
What I want ideally is to concatenate the two values in the form {MemberNumber}{GroupId} and expose this as the Id value. I would then use a Custom Type to handle how these values are concatenated when retrieved from the DB and broken apart when saving/selecting.
I have noticed that the "CompositeId" method does not allow a customType as with the standard "Id" call; but the "Id" method does not provide the ability to set multiple columns. I have seen examples where people have used "Map" to combine two columns using a custom type, but not for id values.
I have noticed the "CompositeId" has an overload that can take a custom identity class but I am unsure how to use it in this scenario.
CompositeId<OfferedProductIdentifier>(x => x.?)
Any help would be greatly appreciated.
in case someone comes here
CompositeId()
.KeyProperty(t => t.Id, c =>
c.Type(typeof(MyUserType)).ColumnName("MemberNumber").ColumnName("GroupId"));
Related
I've joined a team that uses non standard names for tables and columns, and have trouble building database-first projects with Entity Framework.
Here's my problem:
tFWAClientProcessing (Table)
FWAClientHandling (Primary Key, INT)
iClientID (Foreign Key, INT)
.
tClients (Table)
AClientID (Primary Key, INT)
sClientName (VARCHAR(255))
I need Entity Framework to detect the relationship between these two tables without making changes to those tables in production.
I'd long given up on EDMX and convention-based mapping for relationships and just set up EF via EntityConfiguration classes. Attributes in the entity definitions are another option which should work for simple cases like identifying column names. You can also wire up mapping in the OnModelCreating override directly.
For instance: To have entities called Client and FWAClientProcessing for that table structure:
public class Client
{
public int ClientId { get; set; }
public string ClientName { get; set; }
}
public class FWAClientProcessing
{
public int FWAClientProcessingId { get; set; }
public virtual Client Client { get; set; }
}
public class ClientConfiguration : EntityTypeConfiguration<Client>
{
public ClientConfiguration()
{
ToTable("tClients"); // assumes default schema, i.e. "dbo" in SQL Server. Can add schema name as 2nd parameter otherwise.
HasKey(x => x.ClientId)
.Property(x => x.ClientId)
.HasColumnName("iClientID");
Property(x => x.ClientName)
.HasColumnName("sClientName");
}
}
public class FWAClientProcessingConfiguration : EntityTypeConfiguration<FWAClientPrcessing>
{
public FWAClientProcessingConfiguration()
{
ToTable("tFWAClientProcessing");
HasKey(x => x.FWAClientProcessingId)
.Property(x => x.FWAClientProcessingId)
.HasColumnName("FWAClientHandling");
HasRequired(x => x.Client)
.WithMany()
.Map(x => x.MapKey("iClientID"));
}
}
Assuming that the EntityTypeConfiguration classes are in the same assembly as the entities, and the DBContext, registering them in the context becomes:
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Configurations.AddFromAssembly(TypeOf(YourDbContex).Assembly);
base.OnModelCreating(modelBuilder);
}
These examples are for EF6, EF Core uses the concept of Shadow Properties for mapping FK relationships without exposing FK properties, and can accommodate the different column naming. EntityTypeConfiguration is available as an Interface with a Configure method accepting the builder.
I favor using the explicit entity type configuration by default as it keeps the configuration nicely isolated and out of the way and can handle all mapping scenarios that might come up that annotations cannot do. It's a bit of a one-off cost to set up, but at least then you have full visibility and control over how the schema is mapped and not simply hoping EF works things out. :)
Use the modern replacement for EDMX-based Database-First and reverse-engineer a code-first model from the existing database. Customizing an EDMX-based model with its mappings is a rabbit-hole of obsolete technology.
This is available for EF Core and EF6.
The reverse-engineered model is then a starting point for you to make model customizations, like mapping the tables and columns to sensible names, and configuring any Navigation Properties that for whatever reason didn't get picked up by the tooling.
You are right, it is easier if people follow the entity framework conventions. However, if you have to deviate from them, OnModelCreating is your friend.
In OnModelCreating, from every Table, column, relation between tables, that are not standard, you can inform entity framework about these deviations.
You can give different table names
You can use other column names
You can say that certain properties should be saved in certain database formats, for instance ProductPrice is a decimal with 2 digits after the decimal point, instead of the default number of digits.
etc.
There seems to be a one-to-many relation between Clients and ClientsProcessing: every Client with primary key Id, has zero or more ClientsProcessings, every ClientProcessing belongs to exactly one Client, namely the Client that the foreign key ClientId refers to.
You want to use unconventional table names, unconventional names for you primary and foreign keys, and you need to inform about what keys are used to define the one-to-many relation.
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
// Configure DbSet<Client>:
ver clients = modelBuilder.Entity<Client>();
clients.ToTable("tClients")
.HasKey(client => client.Id)
// property Id should be in "AClientID"
clients.Property(client => client.Id).HasColumnName("AClientID");
clients.Property(client => client.Name).HasColumnName("sClientName");
Apart from different names of the columns, you can also declare whether the properties are required or optional, what format they should have (is a decimal with two digits after the decimal point, or does it have four digits?), etc.
Do something similar for modelBuilder.Entity<ClientProcessing>();
For the one-to-many relation: every Client has zero or more ClientProcessings; every ClientProcessing belongs to exactly one (required!) Client, namely the foreign key that ClientId refers to:
clients.HasMany(client => client.ClientProcessings)
.WithRequired(clientProcessing => clientProcessing.Client)
.HasForeignKey(clientProcessing => clientProcessing.ClientId);
Or if you want, you can start at ClienProcessing: every ClientProcessing has exactly one Client (required!), using foreign key ClientId. Every Client has many ClientProcessings.
modelBuilder.Entity<ClientProcessing>()
.HasRequired(clientProcessing => clientProcessing.Client)
.WithMany()
.HasForeignKey(clientProcessing => clientProcessing.ClientId);
Note: by default this will cascade on delete: whenever you delete a client, you will also delete all its processings: you did define there are no processings without a client.
In some relations, you don't want this, especially many-to-many relations or one-to-zero-or-one relation: a Student may have zero or one School-supplied-Laptop. If you delete the Laptop, you don't want to delete the Student as well. In that case you'll have to add .WillCascadeOnDelete(false)
Given the following classes:
public class Mission
{
private MissionCard _missionCard;
}
public class MissionCard
{
}
I would like to create this relationship via Fluent API so that _missionCard is treated as a relationship and can be populated from DB but isn't available as a property on my Mission model.
I can create that relationship with:
modelBuilder.Entity<Mission>().HasOne<MissionCard>("_missionCard");
but by default this creates a FK column named "_missionCard". The docs show that a custom name can be specified when using .Property("property name").FromField("field name") but you cannot use .Property for non-primitive types.
Is it possible to change the column name for a relationship like above?
Managed to resolve this by inverting the relationship:
modelBuilder.Entity<MissionCard>()
.HasMany<Mission>()
.WithOne("_missionCard")
.HasForeignKey(nameof(MissionCard));
I'm working with Fluent nHibernate on a legacy database and have a main Person table and several extension tables containing additional information about the person. These extension tables are one-to-one, meaning that a person will only have one row on the extension table and the extension table should always map back to one person.
Table: Person
Columns: PersonID, FirstName, LastName, etc.
Table: PersonLogin
Columns: PersonID (FK, unique), UserName, Password, etc.
I have my mappings defined as this (with the irrelevant properties omitted):
public PersonMap()
{
Table("Person");
Id(x => x.Id, "PersonID").Not.Nullable();
References(x => x.Login, "PersonID").LazyLoad();
}
public LoginMap()
{
Table("PersonLogin");
Id(x => x.Id, "PersonID").GeneratedBy.Foreign("Person");
References(x => x.Person, "PersonID").LazyLoad();
}
This works when I have data on both tables, but I recently learned that some of the extension tables don't have data for all Person rows. This caused me to get errors during the query. So, I added .NotFound.Ignore() to my PersonMap making it look like this:
References(x => x.Login, "PersonID").LazyLoad().NotFound.Ignore();
That caused me to get unnecessary selects from the Login table due to https://nhibernate.jira.com/browse/NH-1001 when my business layer doesn't need to project any of the extension table values. It is causing the performance to be terrible in some of my search queries.
I've scoured a lot of posts, but haven't found a rock solid answer about how to address this scenario. Below are the options I've tried:
Option One:
Create rows on the extension table to ensure there is no Person without a row on the extension table and then remove the .NotFound.Ignore().
The issue with this option is that it's a legacy database and I'm not sure where I'd need to update to ensure that a PersonLogin is inserted when a Person is inserted.
Option Two:
Remove the PersonLogin reference from my PersonMap and custom load it inside my Person class. Like this:
public class Person
{
/// <summary> Gets or sets the PersonID </summary>
public virtual int Id { get; set; }
private bool loadedLogin;
private PersonLogin login;
public virtual PersonLogin Login
{
get
{
if (!loadedLogin)
{
login = SessionManager.Session().Get<PersonLogin>(Id);
loadedLogin = true;
}
return login;
}
set
{
login = value;
loadedLogin = true;
}
}
}
The issue I'm having with it is that I can't eagerly fetch the data when performing a query to pull back a large number of Person objects and their Logins.
Option Three:
I just started playing to see if I could write a custom IEntityNotFoundDelegate to not throw the exception for these objects.
private class CustomEntityNotFoundDelegate : IEntityNotFoundDelegate
{
public void HandleEntityNotFound(string entityName, object id)
{
if (entityName == "my.namespace.PersonLogin")
{
return;
}
else
{
throw new ObjectNotFoundException(id, entityName);
}
}
}
And I added this to the config
cfg.EntityNotFoundDelegate = new CustomEntityNotFoundDelegate();
It catches my scenario and returns back now instead of throwing the error, but now when I try to project those PersonLogin properties onto my business objects, it's attempting to use the Proxy object and throws this error that I'm trying to figure out if I can handle cleanly (possibly in a IPostLoadEventListener).
System.Reflection.TargetException occurred
Message = Non-static method requires a target
I think I've got this working now by keeping the .NotFound.Ignore().
I originally stated:
That caused me to get unnecessary selects from the Login table due to https://nhibernate.jira.com/browse/NH-1001 when my business layer doesn't need to project any of the extension table values. It is causing the performance to be terrible in some of my search queries.
I was able to tweak my LINQ queries to use the IQueryOver in some instances and to improve my use of LINQ in other scenarios to project only the necessary values. This appears to have resolved the queries from pulling back the extension tables since their values were not needed in the projections.
I thought that my queries weren't projecting these extension tables, but figured out that I had a method ToKeyValuePair that I was using in the projection to concatenate the ID and a Name field together of some related properties. That method was causing the objects to load completely since LINQ wasn't able to determine that the needed fields were present without joining to the extension table.
I have this code in my model for "Application", I'm trying to get all the related "Campaign" objects
public function relations()
{
return array(
'campaigns' => array(self::HAS_MANY, 'Campaign', 'appKey'),
);
}
My problem is, the 'appKey' field in the campaigns table is not the primary key of the applications table and this is what Yii is using to try and find the campaigns.
The primary key of my applications table is 'id' but I would like it to use 'appKey'. How can I update my relations method to do this without making it the primary key?
Thanks.
You could set up a named scope in the Campaign model, like so:
public function byApplication($appKey)
{
$this->getDbCriteria()->mergeWith(array(
'condition'=>'appKey = :appkey',
'params'=>array('appKey'=>$appKey),
));
return $this;
}
And call it like this:
$campaigns = Campaign::model()->byApplication($appKey);
Or, as Irobb said, just set up a query function in your Application model instead of using an actual Relation, like so:
public function getCampaigns() {
return Campaign::model()->findallbyAttributes(array('appKey'=>$this->appKey));
}
And call it like a regular relation on your Application $model:
$campaigns = $model->campaigns; // remember with Yii you can call getters w/o the 'get'
A couple of things... AR is primarily useful for modeling a single table to a class, with a well-defined primary key... Anything else I would use the query builder.
Note: AR is not meant to solve all database-related tasks. It is best
used for modeling database tables in PHP constructs and performing
queries that do not involve complex SQLs. Yii DAO should be used for
those complex scenarios.
http://www.yiiframework.com/doc/guide/1.1/en/database.ar
AR relies on well defined primary keys of tables. If a table does not
have a primary key, it is required that the corresponding AR class
specify which column(s) should be the primary key by overriding the
primaryKey() method as follows,
public function primaryKey() {
return 'id';
// For composite primary key, return an array like the following
// return array('pk1', 'pk2'); }
I have a Project model that has a property of type IProjectWorker, this could either be a single User or a Team. In Castle ActiveRecord it's defined like this:
[Any(typeof(int), MetaType = typeof(string), TypeColumn = "WorkerType", IdColumn = "WorkerID", Cascade = CascadeEnum.None)]
[Any.MetaValue("USER", typeof(User))]
[Any.MetaValue("TEAM", typeof(Team))]
public IProjectWorker Worker { get; set; }
Now I need to be able to search for projects where the worker's name contains some text. My initial reaction was something like this:
query
.CreateAlias("Worker", "Worker")
.Add(Restrictions.InsensitiveLike("Worker.WorkerName", SearchText, MatchMode.Anywhere));
But this gives me an error-- "any types do not have a unique referenced persister". This makes sense, it doesn't know how to handle joining to the two different tables for the search.
Can I make two different aliases for each table and do a Restrictions.Or() across them? I tried it, but couldn't quite get it right. Or is there some other way to do this using criteria that I'm missing? Or am I going to have to use HQL instead?