Using nHib 3.2, I'm interested in caching all my entity's properties, except for a formula property which I would like to be calculated with each Get.
Is this possible?
here's my mapping:
public TransactionNHibernateMapping()
{
Table("TransactionInfo");
Id(transaction => transaction.TransactionId, m => m.Generator(Generators.GuidComb));
Cache(c =>
{
c.Include(CacheInclude.All);
c.Usage(CacheUsage.ReadWrite);
});
Property(transaction => transaction.HighestSeverity, m => m.Formula("(Select max(LogEntryInfo.Severity) from LogEntryInfo where LogEntryInfo.TransactionId = TransactionId)"));
}
now, although 2nd level cache is enabled, this entity is always re-loaded from the database.
If I remove the HighestSeverity property mapping, caching works as expected.
I've tried playing with the Generated option of the formula field, but that didn't seem to help.
any other ideas?
Related
I'm trying to manually scaffold part of an existing database schema in EF Core 2.2. The database in question is part of a 3rd party ERP software, and I have zero control over the design of the database itself, so I'm trying to work with what I am given. So far it's going okay, however I am hitting a snag due to a questionable database design choice by the ERP vendor.
Consider the following one-to-many relationship I'm trying to build in my OnModelCreating() method within my DbContext (via Fluent API):
modelBuilder.Entity<SalesOrderHeader>(s => {
s.HasMany<WorkOrderHeader>(e => e.WorkOrders)
.WithOne()
.HasPrincipalKey(e => e.SalesOrderNumber)
.HasForeignKey(e => e.RelatedPO_SONumber);
});
This is almost what I need, however, in the WorkOrders table "RelatedPO_SONumber" is of type string, where "SalesOrderNumber" in SalesOrderHeaders table is of type int. Further, what's stored in "RelatedPO_SONumber" is a 0-padded string (always 8 characters long) of "SalesOrderNumber" (eg SalesOrderHeader.SalesOrderNumber = 1234567, WorkOrder.RelatedPO_SONumber = "01234567").
Here's what I tried and might help illustrate what I'm trying to do via format specifier (throws ArgumentException "The expression should represent a simple property access: 't => t.MyProperty'"):
modelBuilder.Entity<SalesOrderHeader>(s => {
s.HasMany<WorkOrderHeader>(e => e.WorkOrders)
.WithOne()
.HasPrincipalKey(e => e.SalesOrderNumber.ToString("D8"))
.HasForeignKey(e => e.RelatedPO_SONumber);
});
I tried an alternative approach which was to make another property in my SalesOrderHeader entity definition, and using that as the argument for HasPrincipalKey():
// within SalesOrderHeader
[NotMapped]
public string ZeroPaddedSONumber => SalesOrderNumber.ToString("D8");
// within DbContext OnModelCreating()
modelBuilder.Entity<SalesOrderHeader>(s => {
s.HasMany<WorkOrderHeader>(e => e.WorkOrders)
.WithOne()
.HasPrincipalKey(e => e.ZeroPaddedSONumber)
.HasForeignKey(e => e.RelatedPO_SONumber);
});
This resulted in:
"InvalidOperationException: No backing field could be found for property 'ZeroPaddedSONumber' of entity type 'SalesOrderHeader' and the property does not have a setter."
Is there a way to pass anything other than a strict property reference, but rather a transformed "version" of that property?"
Thanks in advance.
EDIT: Following a suggestion in a comment, I tried this:
modelBuilder.Entity<SalesOrderHeader>(s => {
s.Property(e => e.SalesOrderNumber)
.HasConversion(n => n.ToString("D8"), s => int.Parse(s));
s.HasMany<WorkOrderHeader>(e => e.WorkOrders)
.WithOne()
.HasPrincipalKey(e => e.SalesOrderNumber)
.HasForeignKey(e => e.RelatedPO_SONumber);
});
This doesn't seem to work either, I get the following exception (I get the same exception if I omit the conversion):
The types of the properties specified for the foreign key {'RelatedPO_SONumber'} on entity type 'WorkOrderHeader' do not match the types of the properties in the principal key {'SalesOrderNumber'} on entity type 'SalesOrderHeader'.
I'm using by code mappings and trying to map a manytomany. This works fine but I need OrderBy for the child collection items. I noticed this has been omitted (it does exist in the HBM mappings). e.g.
public class Mapping : EntityMapper<Category>
{
public Mapping()
{
Set(x => x.Items, m =>
{
m.Table("ItemCategories");
m.Key(k => k.Column("CategoryId"));
m.Inverse(true);
m.Cascade(Cascade.None);
}, col => col.ManyToMany(m =>
{
m.Columns(x => x.Name("ItemId"));
//m.OrderBy("Score desc"); // missing in Nh4.x?
}));
}
}
Is there a workaround for this? I tried following the suggestion in this article whereby I can set the property before the session factory is built but it has no effect. e.g.
cfg.GetCollectionMapping(typeof(Category).FullName + ".Items").ManyToManyOrdering = "Score desc";
cfg.BuildSessionFactory();
Am I doing something wrong or is OrderBy on manytomany not supported in Nh4?
Also, is it possible to restrict the maximum number of items retrieved in the collection?
Replaced the many to many with one to many and introduced an entity that represents the relationship (followed advice from this article).
This has the upside of allowing you to map the order-by column as well as other columns, and also solved the issue of restricting the number of items in the collection by using the one-to-many's Where() and Filter() clauses.
I'm trying to wire NCommon and NH to multiple databases via the guidance at http://codeinsanity.com (see 'Configuring NCommon for multiple database support') and it works via the fluent approach suggested, below:
var configuration = NCommon.Configure.Using(adapter).ConfigureState<DefaultStateConfiguration>();
configuration.ConfigureData<NHConfiguration>(config => config.WithSessionFactory(() => _sessionFactories[0]).WithSessionFactory(() => _sessionFactories[1]));
This works as expected but as you can see the sessionFactories are hardcoded. What I'd really like to do is something like this:
foreach(ISessionFactory sessionFactory in _sessionFactories)
{
configuration.ConfigureData<NHConfiguration>(config => config.WithSessionFactory(() => sessionFactory));
}
But this throws the following exception:
Component NCommon.Data.NHibernate.NHUnitOfWorkFactory could not be registered. There is already a component with that name. Did you want to modify the existing component instead? If not, make sure you specify a unique name.
My hope is there's a proper way to wire-up n-SessionFactories without hardcoding them - but I'm just not seeing a solution. Any advice?
I thought I got this to work by delegating the SessionFactory piece to a method, as below:
configuration.ConfigureData<NHConfiguration>(config => ConfigureSessionFactories(config));
private void ConfigureSessionFactories(NHConfiguration configuration)
{
foreach (ISessionFactory sessionFactory in _sessionFactories)
{
configuration.WithSessionFactory(() => sessionFactory);
}
}
However, that only appears to be a solution. Say you have multiple session factories, you can use all of them to query, but only the last-added session factory will hit the database and return results. Queries against the other session factories will never hit the actual database and will return zero entities.
The only way I've been able to get this to work is:
configuration.ConfigureData<NHConfiguration>(config => config.WithSessionFactory(() => _sessionFactories[0]).WithSessionFactory(() => _sessionFactories[1]));
I'd rather not hard-code that though.. I'd much rather iterate over a loop of n-session factories... does anyone have an idea of how to accomplish this?
I've inherited a large set of NHibernate mappings that live in an existing, functional application. I've branched this application to develop some new features, and while I do so I'm also extending the testing infrastructure to allow for a more TDD-like approach. But now I've hit a wall in one of my integration tests...
I have a class with test data, which I insert prior to the integration test. In the method that inserts these, I get the following exception:
NHibernate.PropertyAccessException: Invalid Cast (check your mapping for property type mismatches); setter of Domain.Entities.Project ---> System.InvalidCastException: Unable to cast object of type 'System.Object' to type 'Domain.Entities.ProjectModules'.
and I can't figure out why. I have two Project instances that I try to persist in the database on setup, both defined like this:
new Project("2023", "projeName", "projaddr")
{
PrincipalOwner = UserOne, // UserOne and Office are other properties
Office = Office,
// I've tried just not instantiating this too - gave the same exception
ProjectModules = new ProjectModules
{
HasModuleOne = false,
HasModuleTwo = false
});
});
The (relevant part of the) Fluent NHibernate mapping looks like this:
Component(m => m.ProjectModules, c =>
{
c.LazyLoad();
c.Map(x => x.HasModuleOne)
.Column("ModuleOne").Not.Nullable().Default("0");
c.Map(x => x.HasModuleTwo)
.Column("ModuleTwo").Not.Nullable().Default("0");
});
I've solved this - for some reason, NHibernate didn't like when the component mapping was specified inline in the mapping for Projects, but if I moved the mapping to a separate class ComponentMap<T> it worked. So I changed the problematic lines to
Component(p => p.ProjectModules);
and added the following class to my mappings assembly:
public class ProjectModulesMap : ComponentMap<ProjectModules>
{
LazyLoad.Always();
Map(pm => pm.ModuleOne);
Map(pm => pm.ModuleTwo);
}
Then everything worked as I would have expected it to from the start.
Here's my (simplified) model: Ticket -> Customer Callback (s)
I have my Ticket mapped so that when it's loaded, the Callbacks are as well.
base.HasMany<TechSupportCallback>(x => x.Callbacks)
.KeyColumn(Fields.TRACKED_ITEM_ID)
.Not.LazyLoad()
.Inverse()
.Cache.ReadWrite();
This is not lazy loading because otherwise I'll get 'no session to load entities' when the web service tries to serialize (and load) the proxy. (Using repositories to fetch data.)
It's also bi-directional .. (in the CallbackMap)
base.References(x => x.Ticket)
.Column(Fields.TRACKED_ITEM_ID)
.Not.Nullable();
Now .. we need to show an agent a list of their callbacks - JUST their callbacks.
-- When I query using Criteria for the Callbacks, I cannot prevent the Ticket (and subsequently it's entire graph, including other collections) from being loaded. I had previously tried to set FetchMode.Lazy, then iterate each resulting Callback and set Ticket to null, but that seems to be ignored.
// open session & transaction in using (..)
var query = session.CreateCriteria<TechSupportCallback>()
.SetCacheable(true)
.SetCacheRegion("CallbacksByUserAndGroups")
.SetFetchMode("Ticket", FetchMode.Lazy) // <-- but this doesn't work!
.SetMaxResults(AegisDataContext.Current.GetMaxRecordCount())
;
rValue = query.List<TechSupportCallback>();
rvalue.ForEach(x => x.Ticket = null;); // <-- since this is already retrieved, doing this merely prevents it from going back across the wire
tx.Commit();
// usings end (..)
Should I be doing this with a projection instead?
The problem with that .. is I've not been able to find an example of projections being used to populate an entity, or a list of them -- only to be used as a subquery on a child entity or something similar to restrict a list of parent entities.
I could really use some guidance on this.
[EDIT]
I tried using a projection as suggested but:
I'm getting the following: (this was because of a bug, and so I've since stopped using the cache and it works. http://nhibernate.jira.com/browse/NH-1090)
System.InvalidCastException occurred
Message=Unable to cast object of type 'AEGISweb.Data.Entities.TechSupportCallback' to type 'System.Object[]'.
Source=NHibernate
StackTrace:
at NHibernate.Cache.StandardQueryCache.Put(QueryKey key, ICacheAssembler[] returnTypes, IList result, Boolean isNaturalKeyLookup, ISessionImplementor session)
InnerException:
at
rValue = query.List<TechSupportCallback>();
with the projection list defined like
// only return the properties we want!
.SetProjection(Projections.ProjectionList()
.Add(Projections.Alias(Projections.Id(), ex.NameOf(x => x.ID))) //
.Add(Projections.Alias(Projections.Property(ex.NameOf(x => x.ContactID)), ex.NameOf(x => x.ContactID)))
// ...
)
.SetResultTra...;
rValue = query.List<TechSupportCallback>();
mapped like
public TechSupportCallbackMap()
{
base.Cache.ReadWrite();
base.Not.LazyLoad();
base.Table("TS_CALLBACKS");
base.Id(x => x.ID, Fields.ID)
.GeneratedBy.Sequence("SEQ_TS_CALLBACKS");
base.References(x => x.Ticket)
.Column(Fields.TRACKED_ITEM_ID)
.Not.Nullable();
base.Map(x => x.TrackedItemID, Fields.TRACKED_ITEM_ID)
.Not.Insert()
.Not.Update()
.Generated.Always()
;
// ...
}
This sounds like it's a job exactly for projections.
var query = session.CreateCriteria<TechSupportCallback>()
.SetCacheable(true)
.SetCacheRegion("CallbacksByUserAndGroups")
.SetFetchMode("Ticket", FetchMode.Lazy)
.SetMaxResults(AegisDataContext.Current.GetMaxRecordCount())
.SetProjection(Projections.ProjectionList().
.Add(Projections.Alias(Projections.Id(), "Id")
.Add(Projections.Alias(Projections.Property("Prop"), "Prop")))
.SetResultTransformer(Transformers.AliasToBean<TechSupportCallback>())
;
Simply list all the properties you want to include and exclude the Ticket entity. You can even create a POCO class simply for encapsulating the results of this query. Rather than using an existing entity class.