I have some existing asp.net membership and roles tables in a legacy db and I am mapping them to new entities with Fluent Nhibernate.
I also generate the schema directly from Fluent Nhibernate and I then manually tweak the generated sql script to exclude the existing tables.
Is it possible to say to Fluent Nhibernate to exclude from generation certain tables?
SchemaAction.None() in your ClassMap.
Another option would be to create an attribute, say
public class DoNotAutoPersistAttribute : Attribute
{
}
Then in AutoPersistenceModelGenerator you could check for this attribute in the Where clause of AddEntityAssembly.
I've managed this with an attribute + convention:
public enum SchemaAction
{
None
}
[Serializable]
[AttributeUsage(AttributeTargets.Class)]
public class SchemaActionAttribute : Attribute
{
private readonly SchemaAction schemaAction = SchemaAction.None;
public SchemaActionAttribute()
{
}
public SchemaActionAttribute(SchemaAction schemaAction)
{
this.schemaAction = schemaAction;
}
public SchemaAction GetSchemaAction()
{
return schemaAction;
}
}
/// <summary>
/// overrides the default action for entities when creating/updating the schema
/// based on the class having a Schema attribute (<see cref="SchemaActionAttribute" />)
/// </summary>
public class SchemaActionConvention : IClassConvention
{
public void Apply(IClassInstance instance)
{
object[] attributes = instance.EntityType.GetCustomAttributes(true);
foreach (object t in attributes)
{
if (t is SchemaActionAttribute)
{
var a = (SchemaActionAttribute) t;
switch(a.GetSchemaAction())
{
case SchemaAction.None:
instance.SchemaAction.None();
return;
default: throw new ApplicationException("That schema action:" + a.GetSchemaAction().ToString() + " is not currently implemented.");
}
}
}
}
}
...
[SchemaAction(SchemaAction.None)]
public class TextItem : Entity
...
Related
The story: in our multi-tenant app (one PostgreSql db, multiple schemas) we need to use one DbContext against multiple schemas.
What I tried: holding a cache (Dictionary, where key is schema name, value is the context for that schema). When instatiating new context for another schema I can see that dbContext schema is still set to previous schema provided. I assume the model in context is cached internally by context type, so that is the reason I see this behavior?
So above doesn't seem to work and I found that implementing IModelCacheKeyFactory should do the trick. Does anyone know what should go into Create method though? There are no samples nor documentation anywhere.
What I found:
Dynamically changing schema in Entity Framework Core but it answers for EF6, so not much help.
Here is an example.
Derived DbContext that replaces it's ModelCacheKey (and factory) with a Custom one.
class MyDbContext : DbContext
{
public MyDbContext(string schema)
{
Schema = schema;
}
public string Schema { get; }
protected override void OnConfiguring(DbContextOptionsBuilder options)
=> options
.UseSqlServer("...")
.ReplaceService<IModelCacheKeyFactory, MyModelCacheKeyFactory>();
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.HasDefaultSchema(Schema);
// ...
}
}
The factory that creates the Context with a specific key.
class MyModelCacheKeyFactory : IModelCacheKeyFactory
{
public object Create(DbContext context)
=> new MyModelCacheKey(context);
}
The custom ModelCacheKey per context.
class MyModelCacheKey : ModelCacheKey
{
string _schema;
public MyModelCacheKey(DbContext context)
: base(context)
{
_schema = (context as MyDbContext)?.Schema;
}
protected override bool Equals(ModelCacheKey other)
=> base.Equals(other)
&& (other as MyModelCacheKey)?._schema == _schema;
public override int GetHashCode()
{
var hashCode = base.GetHashCode() * 397;
if (_schema != null)
{
hashCode ^= _schema.GetHashCode();
}
return hashCode;
}
}
There actually have demo project in docs https://github.com/aspnet/EntityFramework.Docs/tree/master/samples/core/DynamicModel adding post for convinience !
I have begun to test Fluent NHibernate in C#
I have a well normalized object structure with 20 related classes.
I currently use Fluent 1.3 with NHibernate 3.2.
So far I have managed to use the AutoMap feature which suits me fine,
Very convenient!
BUT ...
3 of the tables are "enum tables" that need to have their records set with specific Id value.
I tried to make manual mappings of these tables and let the rest be automapped.
But when the manual table is created it fails because it references a table that is automapped (and not available for manual mapper?)
Is it possible to use AutoMapping but for some very few classes override identity creation on primary key?
I tried to make a custom convention but without success.
public class OverrideIdentityGeneration : Attribute
{
}
public class ConventionIdentity : AttributePropertyConvention<OverrideIdentityGeneration>
{
protected override void Apply(OverrideIdentityGeneration attribute, IPropertyInstance instance)
{
instance.Generated.Never();
}
}
Is there some other way?
It would be sad to be forced back to use manual mapping for all classes ....
class MyIdConvention : IIdConvention
{
public void Apply(IIdentityInstance instance)
{
if (instance.EntityType == ...)
{
instance.GeneratedBy.Assigned();
}
}
}
Update:
for enum-like classes it's often easier to define an enum as id
class ConfigValue
{
public virtual Config Id { get; set; }
}
// the convention is easy
if (instance.EntityType.IsEnum)
{
instance.GeneratedBy.Assigned();
// to save as int and not string
instance.CustomType(typeof(Config));
}
// querying without magic int values
var configValue = Session.Get<ConfigValue>(Config.UIColor);
I used the idea given by Fifo and extended it to use a custom attribute instead.
To make code readable and avoid redundance when using similar idea in other conventions I added an extension method to check for custom attribute.
This is the code I ended up with:
/// <summary>
/// Convention to instruct FluentNHIbernate to NOT generate identity columns
/// when custom attribute is set.
/// </summary>
public class ConventionIdentity : IIdConvention
{
public void Apply(IIdentityInstance instance)
{
if(instance.CustomAttributeIsSet<NoIdentity>())
instance.GeneratedBy.Assigned();
}
}
/// <summary>
/// Custom attribute definition.
/// </summary>
public class NoIdentity : Attribute
{
}
/// <summary>
/// Example on how to set attribute.
/// </summary>
public class Category
{
[NoIdentity]
public int Id { get; set; }
public string Name { get; set; }
}
public static class IInspectorExtender
{
/// <summary>
/// Extender to make convention usage easier.
/// </summary>
public static T GetCustomAttribute<T>(this IInspector instance)
{
var memberInfos = instance.EntityType.GetMember(instance.StringIdentifierForModel);
if(memberInfos.Length > 0)
{
var customAttributes = memberInfos[0].GetCustomAttributes(false);
return customAttributes.OfType<T>().FirstOrDefault();
}
return default(T);
}
}
My aim is to implement a quite generic search mechanism. Here's the general idea:
you can search based on any property of the entity you're searching for (for example- by Employee's salary, or by Department name etc.).
Each property you can search by is represented by a class, which inherits from EntityProperty:
public abstract class EntityProperty<T>
where T:Entity
{
public enum Operator
{
In,
NotIn,
}
/// <summary>
/// Name of the property
/// </summary>
public abstract string Name { get; }
//Add a search term to the given query, using the given values
public abstract IQueryable<T> AddSearchTerm(IQueryable<T> query, IEnumerable<object> values);
public abstract IQueryable<T> AddSortingTerm(IQueryable<T> query);
protected Operator _operator = Operator.In;
protected bool _sortAscending = false;
public EntityProperty(Operator op)
{
_operator = op;
}
//use this c'tor if you're using the property for sorting only
public EntityProperty(bool sortAscending)
{
_sortAscending = sortAscending;
}
}
all of the properties you're searching / sorting by are stored in a simple collection class:
public class SearchParametersCollection<T>
where T: Entity
{
public IDictionary<EntityProperty<T>,IEnumerable<object>> SearchProperties { get; private set; }
public IList<EntityProperty<T>> SortProperties { get; private set; }
public SearchParametersCollection()
{
SearchProperties = new Dictionary<EntityProperty<T>, IEnumerable<object>>();
SortProperties = new List<EntityProperty<T>>();
}
public void AddSearchProperty(EntityProperty<T> property, IEnumerable<object> values)
{
SearchProperties.Add(property, values);
}
public void AddSortProperty(EntityProperty<T> property)
{
if (SortProperties.Contains(property))
{
throw new ArgumentException(string.Format("property {0} already exists in sorting order", property.Name));
}
SortProperties.Add(property);
}
}
now, all the repository class has to do is:
protected IEnumerable<T> Search<T>(SearchParametersCollection<T> parameters)
where T : Entity
{
IQueryable<T> query = this.Session.Linq<T>();
foreach (var searchParam in parameters.SearchProperties)
{
query = searchParam.Key.AddSearchTerm(query, searchParam.Value);
}
//add order
foreach (var sortParam in parameters.SortProperties)
{
query = sortParam.AddSortingTerm(query);
}
return query.AsEnumerable();
}
for example, here's a class which implements searching a user by their full name:
public class UserFullName : EntityProperty<User>
{
public override string Name
{
get { return "Full Name"; }
}
public override IQueryable<User> AddSearchTerm(IQueryable<User> query, IEnumerable<object> values)
{
switch (_operator)
{
case Operator.In:
//btw- this doesn't work with nHibernate... :(
return query.Where(u => (values.Cast<string>().Count(v => u.FullName.Contains(v)) > 0));
case Operator.NotIn:
return query.Where(u => (values.Cast<string>().Count(v => u.FullName.Contains(v)) == 0));
default:
throw new InvalidOperationException("Unrecognized operator " + _operator.ToString());
}
}
public override IQueryable<User> AddSortingTerm(IQueryable<User> query)
{
return (_sortAscending) ? query.OrderBy(u => u.FullName) : query.OrderByDescending(u => u.FullName);
}
public UserFullName(bool sortAscending)
: base(sortAscending)
{
}
public UserFullName(Operator op)
: base(op)
{
}
}
my questions are:
1. firstly- am I even on the right track? I don't know of any well-known method for achieving what I want, but I may be wrong...
2. it seems to me that the Properties classes should be in the domain layer and not in the DAL, since I'd like the controller layers to be able to use them. However, that prevents me from using any nHibernate-specific implementation of the search (i.e any other interface but Linq). Can anybody think of a solution that would enable me to utilize the full power of nH while keeping these classes visible to upper layers? I've thought about moving them to the 'Common' project, but 'Common' has no knowledge of the Model entities, and I'd like to keep it that way.
3. as you can see by my comment for the AddSearchTerm method- I haven't really been able to implement 'in' operator using nH (I'm using nH 2.1.2 with Linq provider). any sugggestions in that respect would be appriciated. (see also my question from yesterday).
thanks!
If you need good API to query NHIbernate objects then you should use ICriteria (for NH 2.x) or QueryOver (for NH 3.x).
You over complicating DAL with these searches. Ayende has a nice post about why you should not do it
I ended up using query objects, which greatly simplified things.
I have two tables, Locations and Facilities
They map to two classes,
public Location : Entity
{
//properties
}
public Facility : Entity
{
public virtual Location Location { get; set; }
}
Everything works just dandy, until I change facility to this
public Facility : Location
{
}
Now I get an exception from nHibernate saying
NHibernate.ADOException was unhandled by user code
Message=could not execute query
InnerException: System.Data.SqlClient.SqlException
Message=Invalid object name 'Facility'.
For some reason it is not creating the plural name of the table into the sql string.
Thanks for any help!
EDIT
This is my current TableNameConvention
public class TableNameConvention : IClassConvention
{
public void Apply(FluentNHibernate.Conventions.Instances.IClassInstance instance)
{
instance.Table(Inflector.Net.Inflector.Pluralize(instance.EntityType.Name));
}
}
When Facility inherits from Entity, the Facility does run through this method. When it inherits from Location, it does not
Edit 2
Figured I'd post everything...
public class AutoPersistenceModelGenerator : IAutoPersistenceModelGenerator
{
#region IAutoPersistenceModelGenerator Members
public AutoPersistenceModel Generate()
{
var mappings = new AutoPersistenceModel();
mappings.AddEntityAssembly(typeof(Person).Assembly).Where(GetAutoMappingFilter);
mappings.Conventions.Setup(GetConventions());
mappings.Setup(GetSetup());
mappings.IgnoreBase<Entity>();
mappings.IgnoreBase(typeof(EntityWithTypedId<>));
mappings.UseOverridesFromAssemblyOf<AutoPersistenceModelGenerator>();
return mappings;
}
#endregion
private Action<AutoMappingExpressions> GetSetup()
{
return c =>
{
c.FindIdentity = type => type.Name == "Id";
};
}
private Action<IConventionFinder> GetConventions()
{
return c =>
{
c.Add<BHP.DEC.Data.NHibernateMaps.Conventions.ForeignKeyConvention>();
c.Add<BHP.DEC.Data.NHibernateMaps.Conventions.HasManyConvention>();
c.Add<BHP.DEC.Data.NHibernateMaps.Conventions.HasManyToManyConvention>();
c.Add<BHP.DEC.Data.NHibernateMaps.Conventions.ManyToManyTableNameConvention>();
c.Add<BHP.DEC.Data.NHibernateMaps.Conventions.PrimaryKeyConvention>();
c.Add<BHP.DEC.Data.NHibernateMaps.Conventions.ReferenceConvention>();
c.Add<BHP.DEC.Data.NHibernateMaps.Conventions.TableNameConvention>();
};
}
/// <summary>
/// Provides a filter for only including types which inherit from the IEntityWithTypedId interface.
/// </summary>
private bool GetAutoMappingFilter(Type t)
{
return t.GetInterfaces().Any(x =>
x.IsGenericType &&
x.GetGenericTypeDefinition() == typeof(IEntityWithTypedId<>));
}
}
Have you set a convention?
public class TableNameConvention : IClassConvention
{
public void Apply(FluentNHibernate.Conventions.Instances.IClassInstance instance)
{
string typeName = instance.EntityType.Name;
instance.Table(Inflector.Net.Inflector.Pluralize(typeName));
}
}
This is an old question, but for the sake of others who stumble upon this looking for an answer, you can also create a convention that uses the built-in PluralizationService that comes with EF:
public class TableNameConvention : IClassConvention
{
public void Apply(IClassInstance instance)
{
string typeName = instance.EntityType.Name;
instance.Table(PluralizationService.CreateService(CultureInfo.CurrentCulture).Pluralize(typeName));
}
}
I am trying to write a naming strategy for NHibernate that will prefix table names based on what assembly the poco is defined in. Right now my strategy is just trying to append any prefix at all to the tables just to prove I have things wired up right.
The problem that I am encountering is that I am able to create my INamingStrategy and attach it to the NHibernate configuration object, but it never seems to get used. Here is some example coded:
private MsSqlConfiguration GetDatabaseConfiguration()
{
var configuration = MsSqlConfiguration.MsSql2008
.ConnectionString(ConfigFileReader.GetConnectionString(ConnectionStringKey))
.ShowSql();
return configuration;
}
private FluentConfiguration GetFluentConfiguration()
{
return Fluently.Configure().Database(GetDatabaseConfiguration())
.Mappings(m =>
{
foreach (var assembly in GetAssembliesToLoadMappingsFrom())
m.FluentMappings.AddFromAssembly(assembly);
});
}
public global::NHibernate.Cfg.Configuration GetNHibernateConfiguration()
{
var nHibernateConfiguration = GetFluentConfiguration().BuildConfiguration();
var namingStrategy = GetNamingStrategy();
if (namingStrategy != null)
nHibernateConfiguration.SetNamingStrategy(namingStrategy);
return nHibernateConfiguration;
}
public void Build()
{
var schemaExport = new SchemaExport(GetNHibernateConfiguration());
schemaExport.Create(true, true);
}
By placing a breakpoint on the return statement in GetNHibernateConfiguration(), I am able to confirm that nHibernateConfiguration.NamingStrategy contains a reference to my strategy. However, placing breakpoints in every one of the INamingStrategy implementing members of that strategy shows that non of them are ever called. This is confirmed by looking at the generated schema, which has no prefixes.
Likewise, using the same approach to create a session factory, shows that CRUD operations also ignore the strategy.
I am I missing something obvious?
I am using NHibernate 2.1.1.4000
I think your strategy is too complicated. If you are using FluentNHibertate just provide the TableName convention into your initialization.
e.q.:
public class TableNameConvention : IClassConvention
{
public void Apply(IClassInstance instance)
{
instance.Table(Inflector.Net.Inflector.Pluralize(instance.EntityType.Name));
}
}
and usage here:
public class AutoPersistenceModelGenerator : IAutoPersistenceModelGenerator
{
/// <summary>
/// Get Conf Setup
/// </summary>
/// <returns>
/// Action of AutoMappingExpressions
/// </returns>
private Action<AutoMappingExpressions> GetSetup()
{
return c =>
{
c.FindIdentity = type => type.Name == "Id";
c.IsBaseType = this.IsBaseTypeConvention;
};
}
private Action<IConventionFinder> GetConventions()
{
return c =>
{
c.Add<PrimaryKeyConvention>();
c.Add<ReferenceConvention>();
c.Add<HasManyConvention>();
c.Add<TableNameConvention>();
c.Add<PropertyNameConvention>();
};
}
public AutoPersistenceModel Generate()
{
var model =
new AutoPersistenceModel()
.AddEntityAssembly(Assembly.GetAssembly(typeof(User)))
.Where(
this.GetAutoMappingFilter).Conventions.Setup(this.GetConventions()).Setup(this.GetSetup()).
UseOverridesFromAssemblyOf<AutoPersistenceModelGenerator>();
return model;
}